Step wedge film test question

[k_redder]

:confused:I was looking to revisit my film testing using a different approach than I had used previously and I wanted to use a step wedge (like the one below) to relate densities to actual print values that I get with my "system" (equipment, materials and methods) and I have a couple of questions that I'm sure someone here can help me with. First off, this step wedge is in increments of .15 which allegedly represent 1/2 stop each. If I was to put this in my enlarger and print it using a "Normal" (grade 2 filter) so that Step 2 shows the slightest bit of value above pure black (making that Zone I), should I expect to find a Zone IX print value (last noticeable value before white paper base) at around Step 18?
I have a bunch of other questions, but I'll ask them in subsequent posts (if there are any). Thanks in advance.
82840

[203Ektar]

:confused:I was looking to revisit my film testing using a different approach than I had used previously and I wanted to use a step wedge (like the one below) to relate densities to actual print values that I get with my "system" (equipment, materials and methods) and I have a couple of questions that I'm sure someone here can help me with. First off, this step wedge is in increments of .15 which allegedly represent 1/2 stop each. If I was to put this in my enlarger and print it using a "Normal" (grade 2 filter) so that Step 2 shows the slightest bit of value above pure black (making that Zone I), should I expect to find a Zone IX print value (last noticeable value before white paper base) at around Step 18?
I have a bunch of other questions, but I'll ask them in subsequent posts (if there are any). Thanks in advance.
82840

Check out this YouTube video (http://www.youtube.com/watch?v=K_yK4FqC9zU&list=UUIsGXxMVXuqXIlbCkI60JeQ&index=21&feature=plcp) from the View Camera Store. I think it is just what you're looking for.

[k_redder]

Check out this YouTube video (http://www.youtube.com/watch?v=K_yK4FqC9zU&list=UUIsGXxMVXuqXIlbCkI60JeQ&index=21&feature=plcp) from the View Camera Store. I think it is just what you're looking for.

Thanks for the link. What I'm really trying to do is find a target density to shoot for in my film development testing. Here's a scenario.... let's say I decide to target a Zone IX density to do my film testing around (see here: http://www.alanrossphotography.com/2009/06/zone-system-heresy-a-case-for-zone-ix-calibration/ )....
Now let's say I print the step wedge as described (using #2 filter) where step 1 is printed as pure black (Zone 0) and step 2 shows the first hint of value above black (Zone I). When I do this, the last bit of value before pure white paper base (Zone IX) appears at step 14. It seems to me that whatever density exists at step 14 (above fb+f) is the density I need to achieve in my negative to produce a Zone IX value when printed. This seems to make sense to me, but based on this I need a density of 1.95 (13 steps x .15 ea.) to get there. If true I am fine with that, the reason I hesitate is that 1.95 is quite a bit higher than the Zone IX density shown in Alan Ross' charts (at link above) or any of the exposure/density curves in Adams "The Negative". So either my "system" of methods/materials/equipment is that much different than most, or I am going off the rails somewhere.
For those that might be curious, the "system" consists of: Beseler 45MXT w/ Aristo V54 Head, No. 2 Ilford MG filter printed on Adox MCC110 developed in Dektol 1:2 for 3 min. Anybody have an opinion?

[Bill Burk]

1.95 is quite a bit higher than what is usually recommended for Grade 2. I'd be looking for 1.00 to 1.20

Do you have a safelight issue or light leak that gives "more" light to the paper than expected?

Do you normally get very flat prints with the Aristo head? (I have an old greenish Aristo that gives me lower grade than expected with MG paper).

If these aren't the issues, then maybe it's just the difference between standard way of choosing (90% black and .04 white) aims versus your "eye match" method.

[Bill Burk]

This could also be since you are looking at Zone IX where I might be looking at 7 2/3 stops... Even Minor White looked for 1.5 at Zone VIII

[nolindan]

Grade 2 paper has about 5 stops (1.5 OD) of exposure range between black and white. Its contrast in the middle of the HD curve is 0.5 stops of exposure (equivalent to 0.15 OD) per print tone zone.

Since the tail and shoulder of the HD curve are flat it can be really hard to judge where the 0.04/2.0 densities are. This makes it hard to judge a paper's white-black range. And any way, it isn't the paper's white-black range that's important but its ZII-ZVIII range that has to fit with the negative. You ooch things around to get the highlights to look right and dodge/burn the shadows as needed (or vice versa, or both).

You should also realize that your enlarger contributes a significant amount of flare. If you are interested in finding your paper's range then you need to do your tests by contacting the tablet. You should then get more contrast from the tablet and get closer to 10 wedge steps.

As to what density you should develop your film to - the answer is what ever density pleases you. There is no magic number. A lot depends on your aesthetic, what subject matter you shoot, how much flare your enlarger produces, what paper you like to use, how long you like to develop your prints, your toning procedure and where your prints are exhibited.

There is too much emphasis on numbers in the current interpretation of the ZS. First you find how to make a negative that makes a print that pleases you. Then, if you are so inclined, you can take the process apart to find the relationship between negative exposure and negative density - though frankly, IMO, there isn't much to gain from it.

As has been noted before, the ZS boils down to:

Sunny and very bright: Overexpose 1 stop, under develop 15%
Hazy to middling: normal exposure and development
Cloudy and dull: underexpose 1 stop, over develop 15%

As to my personal EI and all that: after 50+ years of taking pictures, developing negatives and making prints I have found that Kodak is dead-on when it comes to film speed and development. If things aren't coming out right then it is my technique that is to blame and that is what needs changing - not the film's speed or developing time.

I'm an Engineer, and as such I'm a professional measurement and calculations geek. But I now leave the spot meter at home and concentrate on seeing. I leave the spot metering to the darkroom - it saves on paper. Different strokes for different folks.

Disclaimer: I am the head of Darkroom Automation, so my views on the matter have a certain prejudice that you should take into account.

[Chuck P.]

Thanks for the link. What I'm really trying to do is find a target density to shoot for in my film development testing. Here's a scenario.... let's say I decide to target a Zone IX density to do my film testing around (see here: http://www.alanrossphotography.com/2009/06/zone-system-heresy-a-case-for-zone-ix-calibration/ )....
Now let's say I print the step wedge as described (using #2 filter) where step 1 is printed as pure black (Zone 0) and step 2 shows the first hint of value above black (Zone I). When I do this, the last bit of value before pure white paper base (Zone IX) appears at step 14. It seems to me that whatever density exists at step 14 (above fb+f) is the density I need to achieve in my negative to produce a Zone IX value when printed. This seems to make sense to me, but based on this I need a density of 1.95 (13 steps x .15 ea.) to get there. If true I am fine with that, the reason I hesitate is that 1.95 is quite a bit higher than the Zone IX density shown in Alan Ross' charts (at link above) or any of the exposure/density curves in Adams "The Negative". So either my "system" of methods/materials/equipment is that much different than most, or I am going off the rails somewhere.
For those that might be curious, the "system" consists of: Beseler 45MXT w/ Aristo V54 Head, No. 2 Ilford MG filter printed on Adox MCC110 developed in Dektol 1:2 for 3 min. Anybody have an opinion?

I recommend this (http://www.amazon.com/The-Variable-Contrast-Printing-Manual/dp/0240802594) book to you. It will help you in testing your paper with the step tablet so that you can determine the "relative" iso range number------the RN determines the contrast grade produced by a particular contrast filter in combo with your paper developer and any toning that you may do. BUT! Not all contrast filters produce a significanly different range number i.e., a #2 filter may not provide much of a difference than a #1 for example. Paper testing in this book lets you know which contrast filter provides a range number that is equivalent to a grade 2 paper contrast, which is a RN of 95 to 115, or dividing by 100 to get the paper's exposure scale value, or log exposure value---.95 (a hard grade 2) to 1.15 (a soft grade 2), the middle of that range is 1.05.

.95 to 1.15--------in theory, a negative with a contrast range (from Zone I to Zone VIII if your're into AA's The Negative) between .95 and 1.15 would seemingly be a perfect match for the range of "normal" grade 2 print contrasts. However, in practice there is some degree of enlarging flare, which means that the image on the paper will be lower in contrast than the image on the negative (unless you are contact printing). So the question is how much additional contrast do you provide to the negative to make up for losses due to enlarging flare. A flare factor of 2, i.e., one stop, i.e., 0.3 log exposure is entirely possible, maybe you think it is only 2/3 of a stop, then use 0.2. Therefore, If you wish to use the middle of the grade 2 range numbers as your starting point, then a negative density range of 1.05+0.3= 1.35 is needed. Perhaps you like the soft end of the grade 2 range, then, .95+0.3 = 1.25.

The You Tube video was fine but it did not tell you how to read that test, IMO. The book I suggest will show you how to do that. In short, you count the number of steps showing tone (don't count step 11 twice though) and then refer to a table in the book for a 21-step tablet that gives the RN based on how many steps you counted. Ex: you may find that your filter #3 has 7 steps of tone, the RN is therefore 95 or a .95 log exposure value-----now you know that your #3 filter (with your paper, paper developer, and toner) is actually only providing a contrast grade of about a hard grade 2. I find that it works nicely.

[Cor]

If you are interested in finding your paper's range then you need to do your tests by contacting the tablet. You should then get more contrast from the tablet and get closer to 10 wedge steps.



Hope the OP does not mind a little bit of hijack on his thread. Just last night I was using a stepwedge to test contrast (I have still 2 boxes of Forte Fortezo in the fridge, although labelled Normali (normal) give harder images than normal I thought: checking with a 21 Stouffer stepwedge I ended up with 9 discernible steps versus 12 discernible steps for Ilford Mg IV FB.)

Anyway I was reading Bruce Barnbaum's book "The art of photography"were he mentioned (if I quote him correctly) that when using a condensor enlarger the contrast of a projected stepwedge is not the same as the contrast of a contact printed step wedge using teh sme enlarger and same filter.

Why would that be?

thanks,

best,

Cor

[nolindan]

Bruce Barnbaum [wrote] ... "when using a condensor enlarger the contrast of a projected stepwedge is not the same as the contrast of a contact printed step wedge" ...

Why?

The biggest reason is flare in the enlarger.

The second reason is stray light that bounces from the illuminated parts (shadows) of the projected image, on to the walls and ceiling, and and then back on to the paper.

This doesn't affect shadows at all but can take a 1/2 to 1 stop off the highlights. This isn't a big deal in practice as it essentially does an automatic flashing exposure resulting in increased highlight detail. The same effect happens in a camera, where the flare helps lift the shadow exposure up off the toe of the film curve.

A little bit of flare is a good thing.

[Ken Lee]

I was reading Bruce Barnbaum's book "The art of photography"were he mentioned (if I quote him correctly) that when using a condensor enlarger the contrast of a projected stepwedge is not the same as the contrast of a contact printed step wedge using teh sme enlarger and same filter.

Why would that be?


Although there's some disagreement about it, the Callier effect (http://en.wikipedia.org/wiki/Enlarger) causes condensor enlargers to yield blocked high values - particularly when compared to cold light enlargers or contact printing. This was nicely documented by Fred Picker in his book Zone VI Workshop (http://www.amazon.com/exec/obidos/tg/detail/-/0817405747/qid=1075561755/sr=1-2/ref=sr_1_2/002-7002570-7186453?v=glance&s=books).

At the time when those tests were done (1971), the Caller effect was already well-known.

[ic-racer]

a projected stepwedge is not the same as the contrast of a contact printed step wedge using teh sme enlarger and same filter.

Why would that be?

thanks,

best,

Cor
Flare

[Stephen Benskin]

Hope the OP does not mind a little bit of hijack on his thread. Just last night I was using a stepwedge to test contrast (I have still 2 boxes of Forte Fortezo in the fridge, although labelled Normali (normal) give harder images than normal I thought: checking with a 21 Stouffer stepwedge I ended up with 9 discernible steps versus 12 discernible steps for Ilford Mg IV FB.)

Anyway I was reading Bruce Barnbaum's book "The art of photography"were he mentioned (if I quote him correctly) that when using a condensor enlarger the contrast of a projected stepwedge is not the same as the contrast of a contact printed step wedge using teh sme enlarger and same filter.

Why would that be?

Cor


As Ken Lee said, it's the Callier Coefficient. For a properly masked negative, the Callier Coefficient has a greater influence than flare. In the LER / NDR chart below, the log exposure range of the paper, which is from contacting, is the same as the negative density range of a negative using a diffusion enlarger. A condenser enlarger requires a negative with a smaller negative density range from the LER. And these numbers include average enlarger flare.

83082

[Bill Burk]

The story about Callier effect I saw explained that both Condenser and Diffusion enlargers allow light through clear parts of the negative the same. But when there is metallic silver in the negative, the directional light of a Condenser enlarger gets scattered to the sides and never makes it through the lens. But in a Diffusion enlarger there is light coming from all directions - and some of the light coming through sideways, gets scattered into the lens. (With a Condenser enlarger no light from the sides bounces down to make up for the light that got scattered away). So you get more contrast with a Condenser enlarger.


---
Same booklet explains Diffusion enlarger isn't exactly same as Contact Printing. Flare affects the enlarger. Flare will reduce the contrast (even with a Diffusion enlarger) about 10%. (This agrees with what Nicholas Linden says about Flare being a big factor).
---

[Cor]

As Ken Lee said, it's the Callier Coefficient. For a properly masked negative, the Callier Coefficient has a greater influence than flare. In the LER / NDR chart below, the log exposure range of the paper, which is from contacting, is the same as the negative density range of a negative using a diffusion enlarger. A condenser enlarger requires a negative with a smaller negative density range from the LER. And these numbers include average enlarger flare.

83082

Thanks for the explanations, guys!

I am still left with a question though (although it's more out of theoretical interest: my results with the stepwedge indicate that the Fortenzo "Normali" Grade is(much) harder than the Ilford MG FB 2 1/2 grade)

When contact printing 21 step wedge (0.15 OD per step) on the fixed grade Fortenzo I count 9 steps (I start from the first step I can visually detect above the exposed border until and including the step which is completely white(compaired with the next step up)) and 12 step for Ilford MG FB contact printed with a 2 1/2 filter in my condensor enlarger (a Durst L1200, it has been mentioned that this is not a full blown condensor enlarger, because the light of the lamp is re-directed by a 90deg mirror and thus bounces around a bit in the condensor housing ii.e some diffusion of the light is taking place).

Anyway that means a Log Exposure Range for Fortenzo of 0.15*9=1.35
and for ilford FB of 0.15*12=1.8

But when looking up in the table which Stephen posted above that would mean that Fortenzo is Grade 1 (Soft) and the Ilford is Grade 0 (very Soft) and this is clearly not the case, so there is a flaw in my reasoning I guess,

Best,

Cor

[Stephen Benskin]

Cor,

You are probably misinterpreting the range. It sounds like you aren't using a densitometer. LER doesn't use the full range of the paper. As for the difference, grades aren't a precise measurement of the LER. That's why ISO changed to using ISOR which is the LER times 100. What you might also be seeing is how the multigrade is reacting to the light source. As you may have noticed, different mulitgrade papers usually have their own set of filters. If you have a multigrade head, it's always best to test the paper's response to the full range of settings. Create a personalized chart.

[Chuck P.]

Thanks for the explanations, guys!

I am still left with a question though (although it's more out of theoretical interest: my results with the stepwedge indicate that the Fortenzo "Normali" Grade is(much) harder than the Ilford MG FB 2 1/2 grade)



A 2 1/2 filter does not necessarily mean that it is a contrast grade 2 1/2. After exposing the tablet and processing the print, there should be at least 3 to 5 pure white steps before you detect the first density change and at least two or more indistinguishable black steps, adjust the printing exposure time to achieve this----count the steps while not counting #11 twice. If you have this, and you counted 12 steps of tone from the first density change at the white end to the last distinguishable step density at the black end............... then by the table I mentioned earier, the Range Number for that filter (a #2.5), with MGFB and given your paper developer, is 170-----------that's a very soft contrast grade 0.

The Fortenzo, if you have exposed the tablet correctly, at 9 steps of tone indicates a RN of 125, that's right in the middle of a contrast grade 1----the light source and the paper developer (and toning) affects the final contrast grade that is actually realized, regardless of the "fixed" grade indicated on the box. With MG papers, carrying out the simple tests to determine the actual contrast grade of each filter and the spacing between them, can reduce paper waste. Why switch to a #2 filter from a #1, with an expectation of increasing print contrast, when it may be proven that doing so produces no significant change in contrast, you may need to go from a #1 to a #3 just to gain the desired contrast change.

[Cor]

Thanks for your time guys!

I am mainly using Ilford papers and Ilford filters in a L1200 Laborator Durst. I am pretty confident that my default filter 2 1/2 is indeed what it is. Printing without the filter gives me pretty much the same contrast, shifting to either 2 or 3 definitely changes the contrast, and when I have a proper exposed negative this 2 1/2 filter gives a good print to my eyes (and others. Or perhaps the other way around: when dialling in a new developer film combination, next to eye balling the negative, a good print (contrast wise) at filter 2 1/2 is my judgement point.

I'm using a 21 steps small Stouffer stepwedge, each step is 0.15 OD. ( and do not use a densitometer)

I see now how easy it is to get lost when not properly conducting these stepwedge experiments and trying to attach numbers to it (well I knew that actually..)

I think a revert to judging my prints..;-)..although these discussions do increase knowledge and insight, thanks for that!

best,

Cor

[ic-racer]

As Ken Lee said, it's the Callier Coefficient. For a properly masked negative, the Callier Coefficient has a greater influence than flare. In the LER / NDR chart below, the log exposure range of the paper, which is from contacting, is the same as the negative density range of a negative using a diffusion enlarger. A condenser enlarger requires a negative with a smaller negative density range from the LER. And these numbers include average enlarger flare.

83082

I may have misread the first few posts, but I think he is using a diffusion enlarger.
I still think flare is the answer.

[Chuck P.]

looks like post #8 started a discussion about condensor enlargers, so easy to get off track sometimes.

[Chuck P.]

...........and when I have a proper exposed negative this 2 1/2 filter gives a good print to my eyes

An no one can really argue against that, it's really all that matters.

[Ken Lee]

I may have misread the first few posts, but I think he is using a diffusion enlarger.
I still think flare is the answer.

My reply in Post # 10 was not to the original question of the thread, but to the question subsequently posed by Cor in Post # 8. Here is what he asked (emphasis added):


I was reading Bruce Barnbaum's book "The art of photography"were he mentioned (if I quote him correctly) that when using a condensor enlarger the contrast of a projected stepwedge is not the same as the contrast of a contact printed step wedge using teh sme enlarger and same filter.

Why would that be?

[ic-racer]

My reply in Post # 10 was not to the original question of the thread, but to the question subsequently posed by Cor in Post # 8. Here is what he asked (emphasis added):


I was reading Bruce Barnbaum's book "The art of photography"were he mentioned (if I quote him correctly) that when using a condensor enlarger the contrast of a projected stepwedge is not the same as the contrast of a contact printed step wedge using teh sme enlarger and same filter.

Why would that be?

Got it, thanks Ken.

[k_redder]

Thanks for the link. What I'm really trying to do is find a target density to shoot for in my film development testing. Here's a scenario.... let's say I decide to target a Zone IX density to do my film testing around (see here: http://www.alanrossphotography.com/2009/06/zone-system-heresy-a-case-for-zone-ix-calibration/ )....
Now let's say I print the step wedge as described (using #2 filter) where step 1 is printed as pure black (Zone 0) and step 2 shows the first hint of value above black (Zone I). When I do this, the last bit of value before pure white paper base (Zone IX) appears at step 14. It seems to me that whatever density exists at step 14 (above fb+f) is the density I need to achieve in my negative to produce a Zone IX value when printed. This seems to make sense to me, but based on this I need a density of 1.95 (13 steps x .15 ea.) to get there. If true I am fine with that, the reason I hesitate is that 1.95 is quite a bit higher than the Zone IX density shown in Alan Ross' charts (at link above) or any of the exposure/density curves in Adams "The Negative". So either my "system" of methods/materials/equipment is that much different than most, or I am going off the rails somewhere.
For those that might be curious, the "system" consists of: Beseler 45MXT w/ Aristo V54 Head, No. 2 Ilford MG filter printed on Adox MCC110 developed in Dektol 1:2 for 3 min. Anybody have an opinion?

The culprit, as it turns out, is the Adox MCC110 paper that I was(!) using. It's a beautiful paper but I had no idea how much lower contrast the paper actually is. Recently, I had a few other papers on hand to run a quick test. I had some of the MCC110, some Ilford MGIV (fiber) and a pack of Oriental VC (fiber). I printed the step wedge with each paper using a #2 filter (Ilford) so that Step 1 printed as pure black (Zone 0) and Step 2 had the first value above pure black (Zone I). This way I could see where the last value before pure white (Zone IX) would fall with each paper. What I got was:

Paper w/#2 | Step where Zone IX print value falls
MCC110 | 14
Ilford MGIV | 11
Oriental | 9

That's a big difference! I then decided to find out what filter I would need to use with the MCC110 to get the same results as the other papers. What I got was:

In order for MCC110 to print Zone IX on step 11 (just like MGIV), I needed to use a # 3 1/2 filter.
In order for MCC110 to print Zone IX on step 9 (just like Oriental), I needed to use a #5 (!!!!)

Holy %$#@! I expected a difference from one paper to the next, but not like that! With that kind of difference you would need to tailor your exposure/dev routine specifically to that paper (which is what I was about to unknowingly do), and I'm not going to do that because as soon as I do, the paper disappears from the market and I'm left with negs that barely print on anything else.
The good news is that my original film testing results were actually pretty accurate and don't need to be re-done after all (Yipee!), all I have have to do is stop using the Adox.

Mystery solved.


BTW Prints were enlargements (to 8x10) from the step wedge, not contact printed.