Most consistent developer method

[Peter De Smidt]

Here's another vote for developing sheet film in a Jobo with an expert drum. This method is very consistent.

[ic-racer]

I bet everyone that has posted a technique has a access to a densitometer, yet no one has posted an edge-to-center density difference for their favorite agitation technique.

[jb7]

I don't have access to a densitometer.

I haven't been developing with a slosher for long,
but my first batch showed greater density around the edges closest to the sides of the tray-
that was with D76 1:3, continuous agitation.
I reckon the reflection of the waves of developer around the edges caused that.
Also, the less quantity of developer used, the more pronounced the effect.

Next I tried HC110, intermittent agitation.
Lifting each edge of the tray once, twice a minute.
That one seems to be going ok, but could still be improved.
A slightly larger tray might help...

And Henry's observation about using plenty of developer is correct...

I'm new to developing larger negs, so I haven't any other method to compare to, apart from developing 4x5 in a Nikor tank, or home made tubes in a Paterson tank,
which also worked ok-

Again, without any densitometry to back it up-


joseph

[mandoman7]

I have a densitometer but I don't use it to test for even development. I think the preferred method is called a flash test, where you expose a sheet to a very evenly lit piece of wood or whatever (zone VII). I had a setting with my enlarger to produce a comparable even exposure to the film. A totally even exposure of a highlight rather than shadow level, as that is where the problems are found.
This evenly flashed sheet, when developed and proofed, will clearly show the areas of uneven development. I developed film for years commercially before doing this test and wished I had done it earlier. Tanks with metal holders, nikor and yankee tanks, and certain tray methods all produced uneven negatives in my tests. Also sheet development with the emulsion up and developer sloshing over the film edges.
Its important to realize that the problem won't show in images with a lot of texture and shadows. Its when you have a clear blue sky that it can really get you. The problem doesn't show itself with a lot of subject matter. You can be thinking its fine when it isn't, really.
If you're developing a lot of film and and starting to get serious, I advise doing yourself a favor and testing your procedures. You don't want to find out after shooting a year of great negatives that they could've been way better. I believe AA's "the Negative" describes a procedure.

[Doremus Scudder]

Uneven development is usually an agitation issue. Too regular agitation builds standing waves or patterns and increases density in those areas. More agitation at the edges, caused by more rapid movement or turbulence of the solution around the sides of the film, gives dense edges. Insufficient agitation causes mottling and bromide drag...

Rotary processing in one direction can be a problem. Developing film in hangers can cause uneven edge developmen (more turbulence around the hanger frame) and bromide drag (from insufficient agitation). Tray processing often causes dense edges due to the extra turbulence around the edges caused by pushing the sheet down into the solution. There are more causes as well.

All of these can be ameliorated/eliminated by an agitation scheme that prevents the defect. The trick is to come up with an agitation scheme that gives gentle, sufficient, and even,but not regular, agitation. Jobo's that change direction work well (but constant agitation reduces edge effects, which are so prized by many of us). Hanger processing needs a practiced touch, as does tray processing, to avoid defects. In the end, all the methods can work well, but the skill requirements increase appreciably for the simplest and most manipulative methods. Some workers find it easier to go with more secure and predictable methods to achieve evenness; Jobo, sloshers, single-negative in a tray, etc., in order to eliminate the skill factor from the equation. Indeed, this is a good choice for those who do not practice a lot or who have dexterity issues. Others of us rely on our experience and skill to deal with the agitation problems.

I get very even negatives tray processing, but that was not always so. I had to learn to immerse the sheets singly, not push them down into the solution too fast when shuffling, turn them during processing, and otherwise "chaoticize" the process a bit through lots of little detailly things that defy easy description. I am constantly working on honing my agitation technique.

I, too, like the "flash test" mentioned above. (However, this must be contact printed. Enlarging it simply adds the light fall-off of the enlarger to the mix.) An occasional test neg mixed in with the regular negatives is a good way to monitor the processing. Use an N+ negative for the most telling results.

The main issue seems to be (to me, anyway) to find an agitation scheme that fits one's abilities and personality and that delivers good results. This is a highly personal choice, but understanding the problems, options and one's proclivities really helps in choosing and refining the most-suited method.

Best,

Doremus Scudder

[uhner]

I suppose I have had some beginners luck. When I started out with large format two years ago I was somewhat intimidated by tray development and hence bought a Combi Plan tank. Since I did not like the long times it takes to fill and empty the tank, and the possible effects this can have on negatives when using short development times, I settled on a minimal agitation regime heavily influenced by the writings of Sandy King and Steve Sherman. This has worked very well, and I have had no issues with uneven development.

I have recently started to use rotary development with BTZS tubes as well. My initial impressions are that the tubes are easy to use and so far all negatives show even development.

[Bruce Watson]

...(but constant agitation reduces edge effects, which are so prized by many of us).

I have never been able to find any science to support this (oft made) claim. Haist talks about it some in his Modern Photographic Processing, but he seems to conclude that agitation has no effect on the creation or not of Mackie lines (edge effects). I don't believe Henry found any evidence tying agitation to edge effects either, or at least he didn't publish it. It seems to be a theory without any actual scientific evidence. And without the science it's impossible to know the truth.

So if you have any published data or scientific evidence to back up this claim please give a citation and/or a URL. I'd love to find the truth about this once and for all.

[Richard Littlewood]

Doremus
Couldn't agree more. There is nothing like photographing an even surface made on an N+ neg then contact printed on G3 to reveal density nasties.

Bruce
I have come to understand that some developers (Rodinal for one) will increase the Mackie line effect with lesser or no agitation. I look foreward to someone coming through with the science part, but I'm sure many folks will have some practical experience.

[mandoman7]

So I'm not alone, but I am, sort of.

[Kirk Keyes]

Some developers have better pH buffering than others. Development releases acidic by-products (halide ions) and a poorly buffered developer will decrease in activity (in the very local environment of the emulsion) and that will help form these edge effects with dilute developers using stand development techniques. Rodinal has little buffering (it uses hydroxide as the base) so that's why it's popular for this. Developers with borax or carbonate will tend to have better buffering than one made with hydroxide.