Selenium intensification dilutions

I have read here and other places about using selenium as an intensifier for thin negatives. I know the obvious answer is to properly expose and develop my films, but occasionally, I get a negative I'd like to print that just lacks sufficient density to create a satisfying print.

My question is.. what dilution is appropriate for this application? I have seen several different dilutions posted for toning and archival preservation of prints, but none specific towards negative intensification.

(BTW, I use Berg Selenium for my prints.)

Cheers,

24 Mar 2009

Toffle:

Might I suggest 1:3 dilution of toner, and start with a 3 to 4 minute soak with constant agitation. Note that I use Kodak's selenium toner.

Hope this helps.

Regards,
Darwin

Hi Toffle, I would go with Darwin's suggestion for dilution and time. In Tim Rudman's book on toning, he reproduces a time/intensity graph (for paper) published by Maco, if I remember correctly, showing that maximum intensification occurs around 5 - 6 minutes, and then falls away. So the same may be true for film.

Selenium toning will only give a moderate intensification however, probably the equivalent of a half grade for printing, and is best applied to a properly exposed, but underdeveloped negative.

If you have access to a two bath sepia toner, this can give a much greater intensification. But use freshly prepared solutions for bleach and toner, otherwise it could cause an irrecoverable loss of density. (Again this works best for a properly exposed, but underdeveloped negative.)

snallan said:

Selenium toning will only give a moderate intensification however, probably the equivalent of a half grade for printing, and is best applied to a properly exposed, but underdeveloped negative...

...(Again this works best for a properly exposed, but underdeveloped negative.)

Click to expand...

From what I understand of the chemical processes, this makes sense. The good news is I know I have some negatives that fit this description. My worst offenders, however, are from my Holga, which are often very badly exposed. (which is why I only use it a couple of times a year) I will try a few experiments, though and see what comes of it.

Thanks for the responses.

Cheers,

Barnbaum suggests diluting selenium toner 1+1. (Barnbaum, "The Art of Photography" Edition 3.1 (2006), pg. 10-30.) I've seen his method work, and it works well for moderate intensification. It increases density with some increase in contrast. There is no change in the grain or grain structure, which happens with most other intensifiers. Maximum effect takes 15 - 20 minutes.

I occasionally have cause to Selenium intensify an under developed negative. For which I use a dilution of 1:3 for 5 minutes at 20C. As Steve has already said you gain about 1/2 grade increase in contrast.

FWIW:

I use 1+2 for 5-6 minutes. This seems to tone the negative to completion, after which no further intensification will take place. I cannot imagine using 15 or 20 minute times as reported above (maybe a misprint...). At any rate, 1+1 or 1+3 will also work. The idea is to completely tone the negative, so err on the side of longer time. If you use a white toning tray and have a wet negative in another tray for comparison, you can see the negative change tone, just like a print. Let it stay in the toning bath for a couple of minutes after it reaches the last observable change.

Keep in mind that selenium toning removes the stain from negatives developed in pyro (and maybe cathecol too). The net result is zero. Some have mentioned that you can regain the stain by soaking the negative in an alkaline bath or in used developer. I can't corroborate this since I haven't tried it yet.

For my pyro negatives that need a little intensification, I have lately been using a bleach/redevelop process. The negative is bleached to completion in a rehalogenating bleach batch (potassium ferricyanide and potassium bromide. I use 20g ferri, 7g bromide / liter, some use 15g each / liter). You can watch the image disappear. After this, redevelop the negative in a staining developer like PMK or Pyrocat for about 150% of normal (I use 12 minutes in PMK). You end up with the original silver image plus the added stain density which intensifies the neg. This can be done in room light. It's easy and effective and will work with negatives that were developed in a non-staining developer to begin with; as long as the second developer is a staining one, you will get extra negative density.

Hope this helps,

Doremus Scudder
www.DoremusScudder.com

Thanks to all for your suggestions. I have seen dilutions for paper anywhere from 1+3 to 1+30. A lot has to do with each person's workflow and technique. I see that for negatives, the lower end of the scale is definitely more appropriate.

Cheers,