Edge effects on film

[swmcl]

Hi,

If I have my understandings correct, the edge effects that are sought after are an increased contrast in parts of an image where there is a large contrast change - like a dark twig against the background of lighter sky. The edge effects are caused by the developer being exhausted processing the sky part of the neg that the twig part gets less development yes?

Are there any other mechanisms that create edge effects ?

Cheers,

Steve

[Jac@stafford.net]

In fifty years of darkroom work I have never seen a significant edge effect regardless of many development techniques.

I look forward to rebuttals with evidence.
.

[ghostcount]

http://www.largeformatphotography.info/forum/showthread.php?15782-Edge-Effects

[Ted R]

I think there is more than one thing that might be called "edge effect" and one of them goes by the name acutance.

[Drew Wiley]

"Mackie line". Differs with the specific film, developer, and often length of development. A favorite 8x10 combination of mine for awhile was HP5 and PMK pyro,
a bit overdeveloped. Wonderful edge effect, yet otherwise with inconspicuous "watercolor grain". In films with poor edge effect, like TMX, it can be artificially
created using unsharp masking (registered film-wise, that is, though everyone at this point knows about digital mimicry of this technique). I lean toward distinct
edge effect in landscape subjects, but prefer less in portraiture. High sulfite "silver solvent" developers like D23 also tend to minimize edge effect. I find the whole
subject important to my personal work, with probably over a thousand prints to prove it.

[ic-racer]

In terms of Large Format (this forum) think the best way to get 'edge effects' without digital process is unsharp masking. Most prints I make from LF negatives have a magnification level too low to see any effects from the developer.

[Argentum]

Hi,

If I have my understandings correct, the edge effects that are sought after are an increased contrast in parts of an image where there is a large contrast change - like a dark twig against the background of lighter sky. The edge effects are caused by the developer being exhausted processing the sky part of the neg that the twig part gets less development yes?

Are there any other mechanisms that create edge effects ?

Cheers,

Steve

Any edge effects you have from development are likely to be removed by a small increase in printing contrast which will show a greater effect and therefore begs the question of whether its something worth persuing.
I would suggest you try rodinal at 1:25 if you want to get very sharp definition of grain edges. The grain may be bigger than usual but will be very well defined.
For seriously obvious edge effects look up print solarization (Man Ray used this technique quite a lot).

[Drew Wiley]

Even on an 11x14 print from 8x10 I can see it from something like HP5 in pyro. The details almost look etched. Beautiful. Even better at 16x20. In smaller 120
format an interesting comparison could be made between TechPan, which is capable of holding a lot of hypothetical detail, but actually has distinctly lower visual
acutance in a print than Pan F, which has pronounced edge effect. Merely boosting development contrast is also related to acutance, but is not really the same
thing at all.

[swmcl]

Well ... here's something I am wondering.

If edge effects are something relating to exhausted developer in very localised areas, then this is never going to happen in a rotary tank is it !? (mainly a statement but a little bit a question too) The only hope of achieving edge effects would be in a tray-developing scenario in my reasoning. Even then, eddy currents in the fluid would need to be minimised.

My experiences with Rodinal have been very poor and I put it down to rotational development. I believe Rodinal is best suited to tray development so I do hear and agree with you Argentum. I do believe there is such a thing as edge effects and that one could achieve such a thing. Drew sounds very experienced with it.

If anyone can let me (or us) know how to achieve edge effects when the fluid is constantly being churned do tell ...

[Argentum]

I think you are correct that rotary development will stop the dev byproduct from creating edge effects. But constant agitation increases grain size and therefore perceived increase in definition can be evident due to the resulting grain structure. That's why I suggested rodinal.

What you are asking for is a technique rather than optimal film/dev combo that will give you perceived sharpness. Sharpness is afterall about edge contrast.

If you don't favour rodinal then try some delta 400 or delta 100 with DDX and see if that gets you the sharpness (edge effect) you think you are looking for.

If you are looking for actual lines at edge boundaries then flashing print at high contrast will do it or use print solarisation. We have no idea of the degree of effect you are looking for and/or whether it really just higher peceived sharpness your're after. One mans edge effect is another mans sharpness.

[Drew Wiley]

Developers can be tweaked for rotary usage. Rotation speed and agitation can be dramatically slowed with a gearmotor change. Solution volumes can be increased. I use either trays for sheets or hand-inversion tanks for roll film, so don't pay much attention to this, though I once did. Solarization is something
utterly different. But masking can be used to control the amount of edge effect - too much and it starts looking phony, just like oversharpening in Photoshop.
I'd rather control it by choice of film and developer, but sometimes use supplementary masking to enhance microtonality instead. And yes, the two can be
distinguished by the specific method of masking.

[Jac@stafford.net]

"Mackie line". [...] In films with poor edge effect, like TMX, it can be artificially
created using unsharp masking

I entirely forgot about Mackie Line. Thanks for that.

Now, with a negative unsharp mask, is there a micro offset one has to make?
.

[ic-racer]

Off topic but for Rollfilm I have used as many as 8 changes of dilute Rodinal in the Jobo with a rotary 1500 tank.
http://www.largeformatphotography.info/forum/showthread.php?23322-Rotary-Processing-Rodinal

[Drew Wiley]

With unsharp masking the amount of "glow" around the image edges is largely determined by the thickness of the diffusion sheet (or sheets) between the two films, as well as the specific masking film and developer. If one is good at it, and has dimensionally stable film base (polyester rather than acetate), and a good
registration punch and frame, it is possible to make non-diffused masks, or barely diffused ones. This is just as involved an overall subject as conventional film
development, with lots of options and controls. But it can be a very elegant way to enhance midtone and highlight microtonality, or bring out shadow separation,
while maintaining overall contrast. Minus development or compensating development, by comparison, simply scrunch up all this. Both FP4 and TMX100 are excellent large format masking films, but only the latter is ideal for small format work due to its finer grain. But FP4 is interesting due to the fact that it has a
gray antihalation layer, which is essentially color neutral, so you can also expose it through the back of the film essentially self-diffuse itself a bit. But with pyro
stained (yellow-green stain) originals, I prefer to use a deep blue light for generating the mask. Masking for color printing is obviously a lot more involved.

[LabRat]

I think that maybe Jac probably has been enjoying edge effects for so long, that they are part of the normal... I forget about it, but when I look at student work, I am often stumped as how they achieved that degree of mush that looks like it was in the processing... Good practice, good choices, attention to detail in every step, and experience do yield great results...

My take on edge effects is to consider that a film negative image is in relief... That in a very small way, it is in 3D... Higher density areas take up more real estate in the depth of the emulsion... That also means that there are "sides" to that density mass... So does one use a high solvent developer (read/fine grain) that will soften the grain build-ups, but start acting on softening the image itself, or if someone who accepts that grain is part of the inherent structure of the image, and gain the benefit that it is not attacking the image itself??? (Or some happy medium between the two points???)

Yes, edge effects exist, but to a greater/lesser degree depending on the developer/film combination... I think most general film developers have been balanced to produce a result that is in between those two examples... Smooth out the grain enough, but still look sharp... The degree is up to personal taste of the user, and the application... A ultra sharp film/developer combination will often look cold/brittle and the laser-engraved-into-steel look can be most unnatural... Or the ultra fine grain developer might cut the film speed too much, and look as soft as a baby's butt...

To the OP, remember that developer exhaustion also means an excess of by-products in the density developing areas on the film that lead to superadditivity, which also causes an increase in activity in the most active density areas, before it completely exhausts... (Like leaving those Mackie lines between higher and lower density areas, due to that lateral development effect AROUND those areas...

Steve K

[Jac@stafford.net]

[...] My take on edge effects is to consider that a film negative image is in relief... That in a very small way, it is in 3D...

I was fascinated when looking at the film emulsion side in strong diagonal light. I imagine that I saw the dense parts in relief. Has anyone else? What can be done with it is another story, or illusion.

Tri-X was changed at some point and I cannot pinpoint the year, but it became less grainy and lost some soul, edge qualities, and I developed the same for twenty years. Gads, how I resent the change. (OTOH, if it is all in my mind .... nah, it is not.)

[goamules]

A picture is worth a thousand words. Anyone got one?

[jp]

I'm not all scientific about edge effect; correct me if I'm wrong (I don't even have to ask for that, but do appreciate it). My theory is that when details are small, edge effect is more prominent (rather than grain which appears by magnification) Contrast among small details is increased but overall contrast "Grade" is not changed. I'll call it "sized based contrast" rather than edge effect.

Here's a 4x5 where it seems crispier where there are bright flecks in the dark rock in the upper half of the photo. I do not scan with any sharpening, nor add any in PS. Any crispiness is partly from the negative, partly from flickr. Flicrk's sharpening can be avoided by looking at the original unresized uploaded scan via flickr if needed.

https://www.flickr.com/photos/13759696@N02/10847243524/

Most of my LF work is soft focus, so edges are aglow from the lens, not any film/developer combination, so I'll set those aside from this discussion.

Image not inline as it's medium format. (tmy2 in pyrocat hd, agitated 5s once per minute. 1 minute of agitation at start, drain at 13.5 min.) This is a boring gray day, but the contrast among the smaller details belies the boring flat light.

https://www.flickr.com/photos/13759696@N02/16439690435/
https://www.flickr.com/photos/13759696@N02/16666521481/

[BetterSense]

I don't think stagnant developer is required for edge effect to happen. Much or most of the development in film does not occur in the surface of the film but in the bulk of the emulsion where diffusion of the fresh developer and byproducts may dominate over what happens in the liquid. I have no data but I aways figured the phenomenon had as much to do with the film, developer, and temperature than agitation which is what everyone fixates on.

[Cor]

I have posted an example of (over the) edge effect here:

http://www.largeformatphotography.info/forum/showthread.php?120047-Underdevelopment-through-Stand-development-possible/page6&highlight=cor+steve+efke , post #51, the whole thread is an interesting read, perhaps my example is not very clear (it also demonstrates bromide drag, a causual effect I think..), I have more extreme ones, but no scans right now..

Best,

Cor

[Doremus Scudder]

No picture at the moment, unfortunately, since I'm not in the same country as my darkroom.

However, I can easily observe the Mackie lines on my negatives with my enlarging magnifier. I shoot 4x5 TXP and TMY mostly and develop in PMK with a reduced agitation scheme. The edge effects are very pronounced with magnification.

Mackie lines and related edge effects occur most strongly where an area of relatively high density is adjacent to an area of much lower density. The developer in the dense area exhausts quickly. Some of this bleeds over the border into the area of less density slowing development along the interface at the very edge of the low-density area. Simultaneously, the more-active developer in the low-density region bleeds over into the higher-density area increasing the activity of the developer in a thin stripe of the high-density area. the result of this is a low-density area with an outline of even lower density abutting a high-density area with an outline of an even higher density. This increases the perception of sharpness at these interfaces due to the increased contrast at the border.

I'm sure that developer type, dilution and activity as well as the agitation scheme and film type all affect the formation of edge effects. One of the reasons I stick with PMK is the edge effects that I get.

Tanning developers harden the emulsion in proportion to the density and do indeed create a relief effect; a physical 3D relief that can be seen in glancing light. Kodachrome slides exhibited this effect quite clearly. Maybe this is what you are seeing, Jac?

[Jac@stafford.net]

[... snip excellent explanation ...]
Tanning developers harden the emulsion in proportion to the density and do indeed create a relief effect; a physical 3D relief that can be seen in glancing light. Kodachrome slides exhibited this effect quite clearly. Maybe this is what you are seeing, Jac?

Dawns the light! Yes, that is where I saw it. Thanks for refreshing my memory. Kodachrome - what a long ago it seems.

[Drew Wiley]

Tanning relief and edge effect are different. Relief is vertical, can indeed be seen on Kodachrome. But tanning relief is significant in carbon printing, dye tranfer
matrices, and a variety of other alternative color processes rarely practiced nowadays. Edge effect itself did tend to be more prominent on old-school thick emulsion films, though this is not strictly the case. Some fine-grained products like Pan-F and Acros exhibit quite a bit of it. But with stained film it can be hard
to assess unless you either print it or look at the neg through a deep blue filter and magnifier. In print is is highly related to degree of enlargement. Like I already mentioned, with pyro-stained HP5plus, the effect can be exquisite up to around 20x24 from an 8x10 neg, but significantly larger than that, the mushiness of the overall grain can start showing. At the other extreme, a stained TMX 8x10 neg might have downright boring edge quality in a 20x24 print. The edge effect is there, but far more limited. But if you enlarged a sharp detailed TMX 8x10 to 40X60 size, the edge effect might become apparent and appropriate. This characteristic is therefore not a set of rules, but an available set of options to be used intelligently, just like other darkroom tricks.

[ic-racer]

I can't post an example because I don't think it [edge effects] are visible in any of my work where I tried to achieve the effect through film development. I can mention that dilute Rodinal does make possible a print that looks 'sharp' to myself and other viewers of the work.

[Jac@stafford.net]

I can't post an example because I don't think it [edge effects] are visible in any of my work where I tried to achieve the effect through film development. I can mention that dilute Rodinal does make possible a print that looks 'sharp' to myself and other viewers of the work.

Grain often does enhance acutance. Grain is my friend.

[Drew Wiley]

Interesting subject. Makes me lust for good ole Super-XX.

[EdWorkman]

So you wanna see Mackie lines/edge effects?
Dilute rodinal say 1:75
Set your daylight tank vertically in the sink
Pour in the developer thru the light trap
Develop normally when the tank is full
When it's done and out of the fixer, you will see the drool strips across the film , but the development will be regular across the MAckie lines
Kodak recommended NOT pouring XTOL into tanks but quickly immerse the reels into the open tank in the dark and I assumed Mackie problem avoidance was behind it.
After experiencing the pouring problem [decades ago] I tilt the tank and pour as fast as practicable to move the top of the developer pool quickly,
as well as to run it down the side of the tank instead of across the [roll] film. SInce my unfortunate experience and tilting I have never produced unintended Mackie lines with any developer and number of reels.
Yes not relevant to sheet film tray processing, just proof that Mackie works
But ons more thing from long ago. When I shot 35mm plus X I was disappointed with "sharpness", so I tried Panatomic X and it was still unsatisfying [ in D-76]. My older brother told me I was doing it wrong -
I should d use dilute Rodinol at least 1:75 and get acutance/edge effects
I did and I did , then used it with 125 EI 120 films, but not TRI X. Tri X got dilute D76 until XTOL came along and I use that for sheet HP5 and TRI X 120

[Jac@stafford.net]

OK, Ed. Enough text. Show us the outcomes, please.
.

[Doremus Scudder]

So you wanna see Mackie lines/edge effects?
Dilute rodinal say 1:75
Set your daylight tank vertically in the sink
Pour in the developer thru the light trap
Develop normally when the tank is full
When it's done and out of the fixer, you will see the drool strips across the film , but the development will be regular across the MAckie lines

Ed,

What you describe is uneven development due to developer contacting part of the emulsion first before the rest is immersed. It is not remotely related to Mackie lines, which are described in my post above. They happen regardless of development evenness if the other conditions are right :)

Doremus

[LabRat]

I suspect that with standing development, that by using very high dilutions of dev, the "cloud" of by-products that hover over high density areas are less in comparison to when using a much stronger stock solution, where without agitation, these "clouds" can become dense and eventually start breaking-up and rolling down (or around) the vertical (or flat) surfaces of the developing film, leaving the dreaded "bromide drag", but at high dilutions, these build very slowly and maybe have a chance to diffuse back into the developer solution (somewhat) before causing (much) damage... (To see "clouds" in action, tray develop a piece of line film under a safelight without agitation, and look at the density areas... There's a cloudy/fuzzy "beard" around them!!!)

I have seen the effect that Ed described, when someone had poured dev into a rollfilm tank, and (strangely enough) had walked away from the tank (absentmindedly) for over an hour, but later finished the stop/fix (as a save)... Very strange slight partial reversal on highlights/contrasty with hard edge effects... Would have been kinda cool if not for the awful bromide drag all over the image...

Steve K

[swmcl]

Thank you Cor for the post #20. I see in that discussion that Steve Sherman has been playing with dilute developers in stand development and edge effects. I consider Steve to be a pretty thorough practitioner myself.

[swmcl]

Doremus,

With all respect, if there is such a thing as latency whereby a film rests in a developer for minutes before the development process really takes off, then it makes no sense that it matters whether a part of a film is immersed before another part a few seconds here and there at the start if the development process. Where the transfer of chemicals does make a difference would be at the end of the development process, not at the start, and the situation would be even more concerning for a stronger developer than a weak one. Drums like the larger professional Jobo drum 3005 / 3006 and the like have a light trap of the same size as the light trap on the 35mm tanks. Jobo can't be bothered making a suitably larger light trap on these drums so they take a significant time to fill and drain in my opinion. It is also true that they need to be angled when filling to get the fastest inflow of chemicals. In fact, further on this point, when you fill a 3005 one doesn't turn it during the filling! So one whole sheet is getting completely immersed while others don't see any chemicals until the drum is laid on its side and rotated several times. The whole process of filling and laying down can take 15 to 20 seconds.

:-)

[Doremus Scudder]

Doremus,

With all respect, if there is such a thing as latency whereby a film rests in a developer for minutes before the development process really takes off, then it makes no sense that it matters whether a part of a film is immersed before another part a few seconds here and there at the start if the development process. ...:-)

Still sounds like a classic recipe for uneven development to me... and it's certainly nothing to do with edge effects.

Anyway, regardless of whatever "latency" (I might say induction time) there is, starting the process unevenly is likely to cause uneven development. The pour-in time with rotary processors is one reason that the manufacturers recommend a water pre-soak.

Best,

Doremus

[EdWorkman]

Jac
Doremus sez I'm full of it
Yeah I've seen examples in macro- or is it micro -enlargements in references
I'm loathe to spend my time digging out a 35 year old neg to defend myself, even tho' I meant it as an exaggerated example that anyone could see

[jaybob20]

These are some of my "living on the edge" 4x5s
https://flic.kr/p/f66Qxm
https://flic.kr/p/f66NhS

There are some others I posted around the same time. I used Rodinal and HC-110 at "minimum amounts" to develop in jobo 6 sheet reel tank.

[Doremus Scudder]

Jac
Doremus sez I'm full of it
Yeah I've seen examples in macro- or is it micro -enlargements in references
I'm loathe to spend my time digging out a 35 year old neg to defend myself, even tho' I meant it as an exaggerated example that anyone could see

Ed,

I think we're just at odds over definitions here. I'm referring to an adjacency effect that is commonly known as a "Mackie line," and is a result of developer exhaustion and carry-over along borders of high and low-density areas that are both being developed at the same time.

I have no doubt that you get some lines on your negatives from areas having contact with developer before others... It's just that a Mackie line, by definition, is made when both areas are developing simultaneously.

Here's the definition from the Ilford Monochrome Darkroom Practice by Jack H. Cootes, p.55. (Downloadable here if you or anyone else is interested: https://archive.org/details/IlfordMonochromeDarkroomPractice ).

"Adjacency effects The sharpness of an image may sometimes be enhanced by what are known as adjacency effects during development. The mechanism can be more easily understood by reference to the image of a sharp edge. During development, the emulsion layer on the heavily exposed side of the edge will accumulate a high concentration of bromide as a by-product of the development reaction. Some of this soluble bromide will tend to migrate from the high-density side of the edge to the low-density, less exposed side, where it will inhibit development and minimize the resulting density along the border, producing what is known as a 'Mackie line'. Conversely, unused developer will tend to move from the less exposed side of the edge to the fully exposed side, where it will boost the density along the line adjacent to the border. This increase in density along one edge of a border, and the reduction of density along the other, improves the apparent sharpness of a print. Much the same enhancement of sharpness is obtained by the use of development-inhibitor-release (DIR) couplers in XPl-400 film."

I'm attaching the accompanying graphic as well:

150909

If you look closely at the graphic, you can see not only a line of increased density in the more exposed side of the negative, but also a thin strip of less density in the less dense area. As I said, I can clearly see Mackie lines in my negs under magnification, and this adjacency of extremes is exactly what I see.

And, since I haven't seen your negatives, I can't really say that you don't have Mackie lines on them, It's just that whatever areas are exhibiting Mackie lines should really hit the developer at the same time...

Best,

Doremus

[Steve Sherman]

Attached are two direct, unmanipulated, sharpened or otherwise corrected scans of two identically exposed pieces of 7"x17" FP 4 film. During the scanning process each negatives information was adjusted in Levels so as to include all the information contained within each particular negative, nothing more and nothing less. I do not know of a way to make the scans any more common to one another to highlight the processing differences and nothing else.

In the interest of full disclosure, I have been taken to task because the Tray processed neg was done with ABC Pyro, one of the most aggressive formulations of Pyro based developers. The other negative was processed Semi-Stand using PyroCat HD developer. Conventional wisdom dictates that the greater the highlight density the greater the inherent contrast the negative will yield. The ABC developed negative measures 1.79 while the PyroCat negative measures 1.33. It should be clear to those willing to listen that the Reduced Agitation negative shows considerable "edge effects" and while not as dense a negative will produce a contraster print all things being consistent in the printing process. This is a result of the development process or technique, it is not based in the Pyro developer used in each case. These negatives were made back in 2003 after I first perfected the Reduced Agitation Process and this test was to confirm to me exactly what was described above in the Highlight Density relationship versus the Processing Technique and in that sense the test was a huge success and stepping stone to further perfecting the technique to my work flow.

With all due respect to this topic and more importantly those contained in this thread, I know there are knowledgable Large Format negative makers contained in this thread and to deny what can be visually seen on a computer screen and quantified in numeric values is unfair and is the exact reason I don't bother with the Forums much anymore, hence I am late to respond to this topic.

If you need further validation, see these two links for completely 100 % unsolicited comments from those who have seen in person my negatives and resulting prints.

http://www.largeformatphotography.info/forum/showthread.php?122845-Example-of-Semi-Stand-vs-Tray-processed-7x17-negative/page4

http://www.largeformatphotography.info/forum/showthread.php?129656-Kudos-to-Steve-Sherman!&highlight=open+house

Scroll to the bottom of the page for more testimonials http://www.steve-sherman.com/workshops.cfm

Cheers,

[swmcl]

Steve,

Your results line up with reality as far as I intuit it. The agitation technique one uses during film development must make a difference to the final result with all developers and all films. Edge effects, in my understanding of the effect, can only be seen when the fluid is not churned regularly. Your reduced agitation process is obviously less agitation than the tray method you used and the results bear that out.

Thank you for taking the time to respond in this thread.

Steve

[Drew Wiley]

Without getting into the hard science of it, edge effect is the practical result of a number of things, and lack of consistent agitation is not necessarily one of them!
I get wonderful edge effect with certain film/developer combinations, yet I NEVER practice anything remotely resembling stand development.

[Drew Wiley]

And sorry, Steve... I believe what you say about those two comparison prints. But seeing something the size of a postage stamp on the web is of little practical
value. The one on the right is so incredibly muddy that I don't see how it factors into this discussion at all. All I can detect is a dramatic difference in contrast
per se between the two images. It is simply impossible to see edge effect in any image that small.

[Steve Goldstein]

Let me wade in with my own personal experience.

A few weeks ago I took Steve Sherman's "Power of Pyro" workshop and wanted to test it out for myself, so I took myself up to New Hampshire and made some images of waterfalls. I wasn't after Great Art, I just wanted something pretty to experiment with. I made two identically-exposed FP4+ negatives at each of several locations. One of each got standard tray development in Pyrocat-HD 1+1+100, the other got Steve's minimal agitation development in a tube per his recipe. A couple of days ago I made a decent and slightly enlarged (2x) print of one tray-developed negative and then made a print from the second negative that approximately matched the middle tonalities of the first print. Both prints were made with an Ilford #1 contrast filter on some Multigrade IV paper I purchased in late 2013, using a V54-equipped cold light head on my (aligned and glass-carrier-equipped) Beseler 45. The minimal-agitation negative required 2/3 less stop exposure than the tray-developed negative. Both prints got a +1/3 stop foreground burn to tone down some bright rocks, but no other manipulation. At a very quick glance they look identical, which was my intent for this experiment.

The minimal-agitation negative produced a print that looked roughly as if I'd used an unsharp mask with the tray-developed negative. The differences in rock textures, the separation of the pine needles, and the detail in a dark rock cleft were all immediately apparent while viewing at arm's-length distance with normal room lighting. The print simply looked sharper and gave the appearance of increased contrast.

Call it what you will, but there is a real difference between these negatives and nominally identical images. This technique may not be appropriate for all subjects, but I'm convinced it's real and useful, and it's another tool in my toolbox (albeit a slow one to use!).

Fred Picker had a big red stamp he used on letters he received asking him whether this or that technique/lens/developer/film/paper would do some particular thing. The stamp said "Try It". It may not be as much fun as arguing on the Interwebs, but you'll be able to see for yourself.

[Drew Wiley]

There are various ways to get from Point A to Point B. I have no interest in criticizing techniques that others find useful. Unsharp masking is a whole suite of options, a whole tool collection in its own right, and not just about edge appearance, which I won't address here. My only gripe is how a particular point was being made in a manner reminiscent of before/after fad diet ads. In the "before", somebody is given salt tablets, drinks a gallon of water, then told to stick their
belly out. In this case, it seemed like the extra effort went into making a "before" image which was especially bland. Most people are shocked at just how sharp any large format print looks, if competently done. And there are all kinds of ways to enhance particulars, if that is desired, or de-emphasize them in certain cases. If someone wants to teach a particular method, that's great. Everybody seems to have their own silver bullet. The more tool options the better, as far as I'm concerned. But they're still all just tools. What is more important is knowing when to use a particular tool, and when not to. As far as Fred Picker was concerned, he did market some really useful gadgets and some fine paper; but he could sure be a snake oil salesman at times too.

[swmcl]

Drew, I agree the images on the monitor are not going to show anything. I'm just taking Steve Sherman's word for it. It would be a pointless activity looking at computer images.

Drew all I'm doing is applying my mind with physics and chemistry thoughts to some of my queries. My contention is that 'edge effects' that come about as a result of a depletion of developer in a locality on the film can only happen if there is a reduction in the movement of the fluid. Possibly also they can only really be seen when there is quite a dilute concentration of developer also. So far, I believe there are a few who have borne this out for themselves. It looks as though the less the agitation, the greater the 'edge effect'.

What you understand as an 'edge effect' may be something different and caused by different mechanisms perhaps ? I do have another mechanism in mind ... what do you call it when the latent image charge on the film is concentrated on one area of the film more than the rest such that the development of the film proceeds at different rates across the film ?? I can't see this phenomenon occurring without a large bias on one area of the film though. A normal image that has shades scattered throughout won't cut it. Perhaps a portrait of a light skinned person with light hair against a darker background might be something where this latent charge thing can be seen. What happens is the denser areas of the negative are developed more than they should be - increasing contrast.

Cheers,

[Cor]

tried to scan one of my images (a print) which in my opinion clearly demonstrates edge effect and Mackie lines. Scanning with my old scanner and software turns out a lot harder as I thought, anyway here it is: First the processing details: (a repeat from my older post, although I believe I used a stand time of 45 minutes not 60).
Let me elaborate a bit on my empirical approach : I was never happy with the shadow rendering of Fomapan100 (I blame it on the horrible reciproke nature of Fomapan) so I ventured into semi-stand development: idea being that the shadow regions would develop more and the high lights would be restrained at the same time.

This approach worked more or less but yielded prints with quite extreme accutance, an unnatural sharpness for landscape for my taste, but very suited for modern architecture.

So now I reserve the combo Fomapan/semi stand for modern architecture: usually I obtain relative thin negatives, but sometimes the negative is quite thick and I see some bromide drag.

Details:

Fomapan 100 at 50 asa

Pre rinse the 4*5 film in water for 3 minutes


Fill a tube with a lid (something similar to a BTZS tube) with 350ml Pyrocat HDC (1+1+250), 20degC

Insert the film in the tube close lid, invert tube for 1 minute

Let stand for 60 min, invert 4 times at 15, 30 & 45 min

etc.


The examples:\\First a almost full scan from the 24*30 cm baryta print, no sharpening applies, it's actually less sharp than the original":
150977

The original has this (almost) over sharpened "Unsharp Mask" look.

Second 2 details on which I used Photoshop the enhance the differences.

See the lines at the top of the roof
150978

Might be bromide drag here, although you would expect a lower density in the sky, right ?

150979

Hope it is a bit clear,




Best
Cor

[Drew Wiley]

I have gone to a lot of trouble, working hard to forget all the chemistry I learned in college. Now I'm just a darkroom alchemist at best. So I will just let extant
explanations of Mackie effect stand. But I do know that it differs from edge enhancement via masking, which is really just a way of diffusing distinct boundaries in contrast. But how pyro interacts with all of this is enough to driven many a quarrel already. And the fact is, different pyro formulas stain differently, especially if you're comparing pyrocat versus pyrogallol. I just know how to enhance this relative to my own needs. But this is still a fine edge thing, whereas unsharp masking can be taken any where from actually sharp to highly diffuse; and PS unsharp masking controls are analogous in degree, if downright ugly and annoying
when overdone. But I obviously gravitate to the more seamless effects of full darkroom control versus electronic simulation.

[Michael R]

Unsharp masking (for edge effect purposes) creates the same type of edge effect as that created in development. There are some subtle differences in relative magnitude, however. An unsharp mask will tend to produce border and fringe effects of equal magnitude, while development tends to favor border effects. But the sensitometry of how these procedures/processes increase microcontrast is the same.

[Drew Wiley]

No it doesn't. Not necessarily. Yeah, I know how to take a stale film, like TMX souped in some conventional developer, and increase "apparent" acutance via unsharp masking. But it still won't look like a print done with a film with inherently better edge effect to begin with, like its cousin TMY. I know how to increase micro-tonality via masking without necessarily accentuating edges at all. But of course, you've technically cut me off at the pass, Michael, but stating unsharp masking specifically for edge purposes. Yet in terms of those edges, it isn't rocket science. With unsharp masking it's simply the amount of applied diffusion. One can even space a Lambertian diffuser a millimeter or two above the film to create a blatant halo. I'm more likely to employ 3-mil or 5-mil frosted mylar in direct contact with the film. I might have made thousands of masks in my time, but frankly, I don't tend to do it very often for basic black and white printing. Too much
of an edge just looks fishy.

[Michael R]

Maybe you're thinking about acutance or edge sharpness, which is different than micro contrast effects, although both are part of the overall subjective sense of "sharpness" in the print.

But the sensitometry of micro contrast edge effects is the same whether it is done via development (diffusion/exhaustion) or unsharp masking.

150992

[Drew Wiley]

I know the difference, but sometimes the practical effect of how we tweak an image overlaps. With masking, the trick is not to overdo it. With native Mackie effect, the result is largely automatic per film type and exp/development regimen. And masking was traditionally taught rather diffuse or unsharp in order to mitigate registration issues. It's a realm I'm quite comfortable in, though I am still learning new things. You get it; but I guess our technical vocabulary is limited, at least mine is.

[Argentum]

I don't think OP has actually stated what he considers an edge effect to look like and how much of it he is thinking will be obvious or not in the neg and print. The question was more about what will enhance or inhibit the effect rather than how you quantify it visually.
The thing is, there are various types of edge/adjacency effects so perhaps the question should have been more specific elaborating on the degree of effect that is being considered by OP.

[Steve Sherman]

I'm not that knowledgable in Photoshop, at least the one that resides in a computer. That said, I can tell you when I compare prints made from an Unsharp Masking technique and my prints produced from Minimal Agitation techniques I use with dilute Pyrocat they are quite different. From a normal viewing distance the prints are quite sharp against each other. At arms length the transition of tonality in my prints is much smoother almost like there is a roundness to the transition of dissimilar tones while the masked prints look artificial and lack the life that the organically produced negatives project in a final print.

[Argentum]

how many of us have 20/20 vision even with our glasses on. About zero of us I rekon.

Then human angle of view which is rendered sharp in our mind is incredibly narrow, barely an inch at 10 feet I think. so whats with all the sharpness and edge effects anyway. I much prefer a more natural look which has far more subtlety about it.
That's not to say i don't like the occasional high contrast poke your eye out type of photograph from time to time, but generally softer is better. I don't mean out of focus, I mean not critically sharp or with high resolution all over.

[swmcl]

Argentum,

My aims with 'edge effects' would stop at a mild increase in perceived sharpness. I would not consider anything too silly and find any garishness visually disturbing. I guess for me, I'd like to make sure of my thinking and processes to reliably get an outcome should I choose a particular process. I'm not saying I would use the same process each time but maybe a slight enhancement might be a good thing to all my negatives!

Cheers,

[LabRat]

how many of us have 20/20 vision even with our glasses on. About zero of us I rekon.

Then human angle of view which is rendered sharp in our mind is incredibly narrow, barely an inch at 10 feet I think. so whats with all the sharpness and edge effects anyway. I much prefer a more natural look which has far more subtlety about it.
That's not to say i don't like the occasional high contrast poke your eye out type of photograph from time to time, but generally softer is better. I don't mean out of focus, I mean not critically sharp or with high resolution all over.

I agree... But having the option to produce negs with some edge effects/perceived sharpness is an important tool as one might be shooting in conditions such as mushy/hazy/flat light, where the sharpest lens image might produce a mushy look, or maybe a nice old lens that is a little flat in contrast might be helped, or the fact that many people expect a LF image to cut on the sharp side, and as we know, the larger the format, the planes of focus are thinner, and can fall off faster and more abrupt (with different planes of focus not as sharp), so sometimes having something that that can blend these a little helps... So a tool...

To me, a nice combination look is where there is a beautiful long scale of tones that flow/weave through details that have a slightly harder edge that increases the perceived sharpness to the eye, and has the effect of "bones" in a skeleton that give the image a form of it's own... Take away one of the above, and the image is too hard or too mushy... (For hard OR soft focus...)

Steve K

[Argentum]

Argentum,

My aims with 'edge effects' would stop at a mild increase in perceived sharpness. I would not consider anything too silly and find any garishness visually disturbing. I guess for me, I'd like to make sure of my thinking and processes to reliably get an outcome should I choose a particular process. I'm not saying I would use the same process each time but maybe a slight enhancement might be a good thing to all my negatives!

Cheers,

Then try rodinal at 1:25 or 1:50 and if thats too much perceived sharpness then try DDX with delta 100 or delta 400 using normal development with either developer.
I think you just need to experiment with film/dev combos until you find the one that suits your taste using your normal procedures.
There is far too much playing about with fancy techniques to get to nowhere special by an awful lot of photographers magic bullet chasing IMO.
Having said that, often results that just look different from what we're used too have an appeal but that appeal frequently doesn't look so good once it becomes our norm. It's like when you have learnt using RC paper and then try FB for the first time. We all say wow that's fantastic. But my bet is that if we all started using FB and then after some time switched to glossy RC we would all say wow that looks fantastic until it became our norm. Anything new and different has an appeal.
After a longer while our tastes become more stable and focus on subtlety and a classic look which has a longer term appeal. But again, an occasional foray into something different may well serve to confirm that the classic look is desireable. That's why classic became classic. It has lasting appeal unlike fashionable appeal which is short lived.
Having said all that, a great image is a great image no matter how its printed or what its edge effects are which only goes to prove that the subject and composition trumps everything else.

[Drew Wiley]

These technique threads inevitably end up as manifestos about what is supposedly the right way to do something. I'm more concerned about the choice of tools and
how one can tailor specific images with intelligent choices. Not every painting looks good with impasto, some look bland without it. But back to masking (not in PS) - it's a way to kill several birds with one stone. I didn't bring that up yet. But not only can one use diffusers to enhance edges, but more important, you can effectively alter the printing curve of the original, bringing out shadow detail, highlight detail, and better midtone microtonality all at the same time. Instead of
compressing the density range with minus development, you use the mask to handle the extremes, which allow the use of a higher paper grade. Edge effect is
a secondary bonus, IF you want this. I really don't like using masks for "noticeable" edge effect unless there is no other option. Less is often more. But none is
still none. And even if, at my age, I do need reading glasses to appreciate the difference, I am going to do everything I reasonably can to make the print talk
the dialect I want it to. But it is not at all unusual for me to print the same negative in several different manners, and end up liking them all, but for distinctly
different reasons.

[Argentum]

well if you need to apply effects to make something that doesn't look good look better then what you have is an image about effects or style. I'm more of a purist in that sense. If it doesn't look good wth simple traditional methods then there is something lacking in the subject selection and composition and I like to spend my efforts on improving those instead of improving my application of effects. This all about making the right choice at the taking stage. Is the subject really worthy of attempting to make an image of it. Will it produce a good image or won't it. If not then don't expose it.
I'm not saying there is only one right way and everything else is the wrong way as we all have different tastes and styles but effects are vastly over used to obscure an underlying lack in the image IMO. That is about trying to make something out of nothing a bit like artists going off the wall to impress just becasue its different and non conventional. Call me conservative if you like. Each to their own....

[Steve Sherman]

well if you need to apply effects to make something that doesn't look good look better then what you have is an image about effects or style. I'm more of a purist in that sense. If it doesn't look good wth simple traditional methods then there is something lacking in the subject selection and composition and I like to spend my efforts on improving those instead of improving my application of effects. This all about making the right choice at the taking stage. Is the subject really worthy of attempting to make an image of it. Will it produce a good image or won't it. If not then don't expose it.


The really sad part of this thread, not one contributor has mentioned the Creative opportunities that Reduced Agitation film development provides, everyone is concerned with edge effects and an increase in acutance. In reality, with extended development times and dilute developers allow for image making in extreme lighting conditions, both high contrast and very low contrast scenes can be manipulated to render full scale Silver prints or Pt. / Pd. if one is so inclined.

Cheers

[Argentum]

I don't see what is sad about answering the OPs question which had nothing to do with expanding or contracting subject contrast to fit the film.

But now you've mentioned it that is another of my pet annoyances. The vast majority of subjects are around 7 stops in range and a certain percentage maybe upto 10 stops which is very easily manageable with normal development by just reducing dev time a perentage and doesn't require using fancy development techniques. Only a very few subjects are in excess of 10 stops range but you'd think it was a high percentage with the amount of talk that goes on about how to compress extreme contrast onto a useable film range. Doing that tends to kill the look of the subject by killing the micro contrast which is precisely what the OP is asking about increasing a tad. And overall contrast a 12 stop subject compressed to fit the 5 to 7 stops of paper is never going to look good. It nearly always looks un-natural without doing a lot of printing somersaults. Its an excercise in making things difficult for yourself.

I've seen quite a few images posted here or on another forum recently which when you look at them its obvious that some weird processing has made them look un-natural.

[Steve Sherman]

I don't see what is sad about answering the OPs question which had nothing to do with expanding or contracting subject contrast to fit the film.

But now you've mentioned it that is another of my pet annoyances. The vast majority of subjects are around 7 stops in range and a certain percentage maybe upto 10 stops which is very easily manageable with normal development by just reducing dev time a perentage and doesn't require using fancy development techniques. Only a very few subjects are in excess of 10 stops range but you'd think it was a high percentage with the amount of talk that goes on about how to compress extreme contrast onto a useable film range. Doing that tends to kill the look of the subject by killing the micro contrast which is precisely what the OP is asking about increasing a tad. And overall contrast a 12 stop subject compressed to fit the 5 to 7 stops of paper is never going to look good. It nearly always looks un-natural without doing a lot of printing somersaults. Its an excercise in making things difficult for yourself.

I've seen quite a few images posted here or on another forum recently which when you look at them its obvious that some weird processing has made them look un-natural.

I can assure you there is more than a 12 stop range

[Drew Wiley]

Now things are getting interesting. So let me go back in time, when I was still struggling with 12-stop-range subjects and trying to keep them crisp and fully textured in the print, without the mushy compression of blocking of shadows inherent to minus or compensating development. This is a fairly routine situation for
me, especially when the fog breaks and full sun arrives in the redwoods. And I absolutely love the cat and mouse game of chasing the constantly changing light,
even if it does inherently constitute a 50/50 gamble that when the darkslide is pulled, the intricate composition will still be the same as I saw it in the groundglass. So of course, the first set of tricks I learned was using staining pyro developer for better highlight control, along with films with a substantial straight line, first Super-XX, then Bergger 200, now TMY. I gave up on Foma 200 due to the slow speed and horrible recip characteristics. Then, luckily for me,
VC papers dramatically improved. But still, something else was needed. Due to all my experience color printing, I knew masking was the key. But like everything
else, the devil is in the details. Then I discovered how to make very low contrast blue-light masks, which basically operate from the opposite end of the yellow-green or yellow-brown pyro stain, equally proportionally. My most common mistake was to over-diffuse these, which actually hides some of the native more delicate Mackie effect or fine-line tracery. Always something new to learn.
effect

[Argentum]

staining developers will show greater sharpness/contrast on graded papers due to stain filtering out blue light. On VC paper the yellow stain softens contrast. Overall contrast can be made same between the two types of paper by developing to suit particular paper type but graded paper shows better micro contrast due to stain effect when printing. At least that was how it was demonstrated to me. Others say that with right development for each paper type there is no difference. I don't think so.

[Drew Wiley]

I've heard that said numerous times, regarding a different effect of pyro stain on graded versus VC paper, and after many many prints on numerous types of paper have concluded it is nonsense.

[Argentum]

I've heard that said numerous times, regarding a different effect of pyro stain on graded versus VC paper, and after many many prints on numerous types of paper have concluded it is nonsense.

If you use the same neg on both types of paper the difference jumps out at you. But if you are using two negs each developed for the specific paper, i.e. to different contrast levels, then the difference is much less obvious. I've seen it with my own eyes. I think we'll just need to agree to differ on this one.

[Drew Wiley]

No it doesn't. Not in my experience, ever. Maybe I'm working with a more universal stain; most of my negs are PMK yellow-greenish. I have less experience with the brownish pyrocat version, though I've fiddled with it and numerous other tweaks. So I'll stand my ground on that boundary line, but not trespass into territory where the nature of the image stain happens to be different. Here's my hypothesis, which might or might not need formal testing to confirm: VC papers achieve their contrast range via the cumulative silver content of mainly two different emulsions, which at the same time saves the expense of a very silver rich single emulsion of a premium graded paper (note "premium", implying quite a bit of contrast flexibility even in a single grade, based on length of development). I've noticed that in order to achieve a full DMax with VC papers, there must be a token amount of exposure to both emulsions, even if the predominant exposure is only to the blue-sensitive layer or the green sensitive. When various yellow or magenta filters are used, either in a colorhead or sheet filters, some of the
exposure reaches the other layer automatically, because subtractive filters always pass a bit of white light, especially in the moderate degree VC needs. With
true split printing, using hard 47 blue or 58 green separation filters, this has to be deliberately introduced. Not all papers respond exactly in the same manner,
so I'm speaking in generalities. But for example, even if I'm trying to achieve maximum contrast using only a deep blue filter, the DMax seems to require a pinch
of green exposure too. The pyro stain itself would logically attentuates blue, but not exclusively, since green light responds to significantly less filter density,
so thing SEEM to come out about the same in practice, or in varying degrees of usage. This latter talking point doesn't enter the usual pyro wars, but it has
become rather apparent to me, probably because I have become familiar with how these hard filters work in relation to color separation negs on similar films,
without the pyro stain.

[Argentum]

My thinking is that that the yellow/green stain stops the micro highlights from being printed down on graded paper whereas on VC paper it doesn't have nearly as much effect. Most likely because there is the green sensitive emulsion which is sensitive to yellow green so the micro highlights do get printed down. So there is an increase in micro highlights, and it is an increase or rather less of a decrease in micro highlights on graded paper.
You seem to be coming at it thinking of getting the extra micro contrast by printing down the shadow portions of micro contrast whereas I think of it as stopping the highlights from being printed down. There is more than a subtle difference there. And even a tad of over printing will kill micro contrast. Graded paper is I think, better at retaining it becasue you are not at the mercy of the secondary emulsion sensitivity.
But I think we could argue about this indefinitely. As always the proof of the pudding is in the eating and I have seen it.

[Steve Sherman]

If you use the same neg on both types of paper the difference jumps out at you. But if you are using two negs each developed for the specific paper, i.e. to different contrast levels, then the difference is much less obvious. I've seen it with my own eyes. I think we'll just need to agree to differ on this one.
Any prints to show this comparison ?

[Drew Wiley]

Well, I've cooked and eaten an awful lot of pudding. Another interesting thing, is that whether I make the print using my blue-green aristo cold-light, a conventional YMC subtractive colorhead, or my RGB additive colorheads, using either mixed light or strict narrow-band split printing, I can come up with virtually identical results. And when it comes to basic unsharp masking as a supplementary subject, even though a single mask obviously carries its own density in what corresponds to the thin areas (shadows) in the main negative, the improvement in microtonality is across the board, and significantly improves highlight repro itself.... at least in my methodology. This combined effect can be densitometer plotted, and then compared with the original neg as well as its mask. But the readings are easier to make on a conventional rather than stained neg.

[Argentum]

Any prints to show this comparison ?
Nope, this was something I played with many years ago but went the VC paper route having decided it gave me far greater control of less than perfect negatives.
Originally it was demonstrated to me by Barry Thorton at a workshop I attended. This was before his books and releasing his developers but his examples may have been created using his dixactol developer pre-production. This developer produces a more green stain than PMK which is more yellow. I played about with PMK a little. BUT the difference was definitely there to be seen.

But I must stress that if you produce negs of exact same subject in same lighting and develop one to fit VC paper and the other to fit graded paper and then compare the results the difference is more subtle whereas if you develop to fit VC paper and then print on graded paper the difference is large. And if you develop to fit graded and then print on VC the print looks flat.
I'm assuming that when printing we're using equivalent contrast setting on VC paper as graded paper is giving us. So if graded is ISO(R) 110 then VC filtration being used gives us ISO(R)110 so that we are comparing like with like.

Now you could say, Ah but we can increase printing contrast on VC to make it more similar to graded. Yes thats true but by doing so you would be reducing print resolution so they will always look slightly different. You may get fairly close if not looking too closely but never the exact same.

[Drew Wiley]

I don't think you can justify statements that generic. Nowadays there are a few VC papers that can be used almost as if they were graded. That actually what I do most of the time, provided that particular paper gives the final image color I am seeking. I just print it as if it were Gr 3 using "white" light, then develop for the degree of contrast and density I seek. Maybe there will be a bit of minor selective exposure through a deep filter afterwards. There just isn't much of a selection of graded papers left anymore. I keep some Ilfobrom Galerie 3 on hand, and some older inventory of E-Maks. But when it comes to warm tones, MGWT is so cooperative with my negs that I might or might not tweak it with typical VC technique. Don't want to get this discussion too complicated, because I am using different enlarger heads. But different brands or emulsions of VC have widely varying personalities themselves, just as graded papers did. You can't just go around making blanket statements about them.

[Doremus Scudder]

I've heard that said numerous times, regarding a different effect of pyro stain on graded versus VC paper, and after many many prints on numerous types of paper have concluded it is nonsense.

+1

Nicholas Linden got plenty exasperated trying to convince this community that pyro stain has no contrast effect with graded vs. VC paper. His research was extensive and convincing. I think he has left the forum now out of frustration.

Doremus

[Cor]

That may be, but in my experience, in my hands, in my darkroom:

I shoot MACO IR 4*5 film quite often, and process it in PyrocatHD. Since measuring light for IR film can be quite unpredictable I some times produce negatives with bullet proof highlights: combined silver and stain density. These negatives are quite hard or sometimes impossible (meaning yielding an acceptable print) to print on Ilford VC paper, the highlights get gray/muddy, there is no snap in the print, and using a higher grade filter does not help, the high stain acts a filter on it self, and in prints with for example clouds never print nice, no matter what. Switching to a fixed grade paper (in my case Foma) brings back the snap and nice clouds. A more drastic approach is bleaching away the Pyro stain, which also does the trick.

Granted these are rather exceptional cases, and it might very well be that the difference between VC and graded paper is negligible when one has a normally processed Pyro negative

Best,

Cor


+1

Nicholas Linden got plenty exasperated trying to convince this community that pyro stain has no contrast effect with graded vs. VC paper. His research was extensive and convincing. I think he has left the forum now out of frustration.

Doremus