John, could you not carefully place the film in a hanger to prevent floating upwards? I've not tried EMA yet, so don't know if this would affect the solution quantity; I have done this when testing to find Stouffer characteristic curve for 4x5 HP5+ with highly dilute HC-110 (1+ 123ml) for 28min @ 20C, but the dev quantity was high enough to permit use of 4-up hanger with two sheets (one with Stouffer shot and one without to check for uniformity).
Originally Posted by John Layton
John, I guess that stock developer should be more prone to make the film float than diluted developers.
It happens like with sea water, a swimmer floats better if the liquid has a higher density. Highly diluted developers won't increase as much the water density, less salts inside.
...so perhaps the test should include different dilutions, for each film.
Another possibility is air bubbles, this may come from tap water having air diluted, and making bubbles after the pressure loss, if we use tap water to dilute developer.
Stand development in any fashion is an attractive idea but in final results it fails. All films have a develop-to-completion time and with highly dilutions they all complete in about 30 minutes, but let the film stand for a six-pack if you like - it makes no difference. Stand development will never compensate for sloppy exposure. Burn that into your bible.
My solution to twisting/floating of the film is to make sure that the total volume of developer is literally right under the cap. The cap has "dimples" in it which provides just a bit of air to ensure good agitation.
Jac, Of course a wrong exposure will ruin the job, but stand has a noticeable effect.
Stand development is a kind of compensating development, it is clear what it makes. As diluted developer exhausts earlier in the highlights, and it is not well refreshed by agitation, then the highlights are less developed, in practice we obtain three effects:
> Film curve is more shouldered
> Film latitude is extended in the highlights side
> Well enhanced microcontrast from edge effects that have a larger radius than with usual processing.
If also using a yellow stain developer we add the stain effect on Variable Contrast paper. As the dense areas (highlights) are yellower than the mids/shadows then in practice we block more blue light there, so selectively we print the highlights with a lower contrast, potentially obtaining better textures.
You forgot one - mid-tones to shadows lack contrast. Stand development is not generally a good practice, a panacea unless one is developing for digital scanning and I think that is not within the scope of this subject.
Jac, I don't agree...
Beyond what we can do in the printing, with stand development you may develop to the Contrast Index you want, by adjusting dilution vs time, like with any regular process. The part of the curve that is modified is in the highlights, contrast in the shadows/mids can be adjusted as always.
If placing an extended scene dynamic range (compressed) in the paper then of course we'll have a dull print, but stand does not presupose that. We can perfectly make a stand development that is Normal contrast, except that the curve will be more shouldered, or with a regular processing we can do anyway a N- compression. Stand does not imposes a compression in the shadows/mids, it only imposes a compression in the highlights, the stand compression in the shadows/mids is optional like in regular processing.
If scanning then stand development is less interesting, because we can bend the curve in Ps like we want, but the microcontrast enhacement from stand is more difficult to imitate in Ps.
No streaks for me using dilute Pyrocat, EMA, in sp445 tank for last 2 years.. Presoak 5 minutes for Ilford films and Initial agitation 2 minutes . Bergger doesn't seem to benefit fron the presoak but I do it anyway while I prepare my developer. Clean everything well between sessions.
The magic you are looking for is in the work you are avoiding.
http://www.searing.photography
If I read this right it is not the developer that sinks to the bottom it is the Bromide. using very dilute developer and a vigorous initial 2 minute agitation avoids the bromide streaks when developing vertically.
Well, as developer makes metallic silver it gets enriched with bromide, so density increases, so that mix falls down.
Last edited by Pere Casals; 16-May-2019 at 10:37.
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