Questions reducing and intensification on negative

[greg zinselmeier]

Hello ALL,

I would like some information ( how to) and which formula's ( preferrably from darkroom cookbook) or( if you could write out your secret formula, LOL) : to use regarding, 1. reducing the thin areas of the negative. and 2. depositing more density on the highlights? AFTER DEVELOPMENT, fixed, and washed film!

I am using 8x10 sheet film. can someone point out which reducer to use? I am assuming I will be using selenium intensifier. the film has an even fog due to " a flashing" of the film that was too strong.

do I reduce first? can I only reduce the thin areas or no?

or can I only intensify? to create more contrast?

thanks in advance.
Greg

 

[cliveh]

This tonal variation is really a question you should ask yourself before you expose and develop the image. Why not treat the cause instead of the effect?

 

[Vaughn]

Someone will chime in with the proper names, but I have used the bleach from Kodak's Sepia Toner kits. One can re-develop if one bleaches too far...then fix when you see what you want.

Timing is important -- do it in a white tray with good lighting (no safe light needed). The shadow areas will bleach first (due to low silver). The neg will lose a little more visible silver once in the fix. Watch the rebate...leave just a hint of fogging and it will be gone in the fixer.

Leave the negative in the bleach a little longer if you want to remove a little shadow information as well as the base fog from the flashing. Again, when one puts the bleached negative in the fixer, some more silver will be removed. The negative can be rinced and bleached again if needed.

If there is enough silver on the negative (well-exposed and developed), then after bleaching and a wash, selenium toning will give you a touch more contrast...selenium just has to have enough silver to work with.

I have done this with negs that were just a little shy of the contrast I wanted for some alt processes where I did not use the contrast controls of the process, but instead depended on getting contrast right on the negative.

 

[koraks]

Someone will chime in with the proper names, but I have used the bleach from Kodak's Sepia Toner kits.

That would probably be a ferricyanide bleach. It's also what I'd suggest. Potassium ferricyanide + potassium bromide, usually. Good call!

For density increase, selenium toning is often used and should do the trick if a modest increase is all that's needed (e.g. for silver gelatin printing). For carbon transfer I like negatives with a huge amount of meat to the bone, in which case I generally use chromium intensifier; it's the only situation I still use dichromate. https://tinker.koraks.nl/photograph...ium-intensifier-for-silver-gelatin-negatives/
If selenium toning is a bottle rocket, chromium intensifier is an Atlas V. Use one for fireworks, the other one if you need to go to the moon - horses for courses!

Obviously, anything done to the negative is generally irreversible.

 

[john_s]

The OP wants to reduce density (excessive pre-flashing) and increase contrast. So someone who knows might suggest a "subtractive" reducer followed by (or maybe preceded by) a contrast increasing "proportional" intensifier. It looks like a tricky balancing act to me.
Maybe reducing a bit could in effect increase contrast on its own?

 

[Andrew O'Neill]

I have no experience with reducing negatives, but I have bleached/redeveloped. I have tons of experience using Selenium Toner (KRST), for increasing the density range of negatives. Not sure why you would want to reduce thin areas on the negative... Selenium intensification has very little if no effect on those areas (depending on the film).

 

[DREW WILEY]

Simple Farmer's Reducer. No longer made by Kodak; but you can get a replacement product from Formulary or concoct it yourself. Experiment with time and dilutions. Must be highly dilute if you want minimal reduction of just fog.

 

[Andrew O'Neill]

Oh! I didn't see that part. Too much density in the shadows from pre-flashing... I wonder if bleach/redevelopment would help.

 

[DREW WILEY]

No need to re-develop. By cutting the base fog using Farmer's, you automatically get more contrast due to deeper blacks. Then selenium intensifier can be used to increase density in the highlight repro portion of the neg, thus further increasing contrast without any need to re-develop.

I've done this hundreds of times in relation to unsharp masking, to fine tune initial results (the Farmer's trick at least). The point is to practice first with otherwise discarded negatives. Just a little cuts just the least dense zones of the neg; too much concentration or time, and it starts affecting the upper midtones too, etc. But since this can be done in daylight in a tray, it's easy to monitor.

 

[Vaughn]

...
Maybe reducing a bit could in effect increase contrast on its own?

Yes. The shadow areas, which have relatively little silver, will bleach faster (see a greater change) than midtones and highlights. This will increase the contrast by dropping the shadow values more than the rest of the negative. None of this works very well on a thin negative.

 

[koraks]

a "subtractive" reducer followed by (or maybe preceded by) a contrast increasing "proportional" intensifier

That's what @Vaughn and me suggested, yes.

 

[greg zinselmeier]

thank you all, for your help, I appreciate the time you all have given this topic.