Is it possible to change contrast of final print?

[olegkasko]

I have a gelatin silver print and I'd like to increase print contrast. If it's possible of course. (I can't make one more print)

So, I know that its possible to whiten a print using Potassium hexacyanoferrate (III), so with this chemical I can make the white details even whiter. (however I have never done it before)
But I wonder if it is possible to make dark details even darker somehow?

Thanks!

[Jeroen]

Farmer solution for highlights, can even be applied locally with a sponge. Selenium toner can increase blackness, so can drying (baryta paper only) on a hot dryer. Drying with chrome plates instead of fabric even more. Don't expect miracles though, I doubt you'll get more than 1/3 grade increase with all processes combined.

[koraks]

If the whites are where they should be but the blacks are lacking to a significant degree, a last resort can be chromium intensification. It'll alter image tone towards green but it does boost contrast considerably.

Of course with any method I'd test on test prints before committing to that one print you can't make again. ..

[cowanw]

Can you photograph the photograph?

[Drew Wiley]

Rephotographing was a popular technique for concocting pre-Photoshop imaginary scenes using composite pictures, and there are still some practitioners of it. Of course, the technique can also be used to enhance or correct basic images, and I often had to do this on the copystand with respect to restored versions of damaged antique original photographs. But there is always a penalty in terms of loss of nuanced tonality; and this is quite apparent even in modern examples in the galleries of people who specialize in this for creative purposes. It's better to go with some of the advice in previous posts. Farmer's Reducer is an easy way to bring out the sparkle in otherwise bland highlights and thus enhance overall contrast. Kodak no longer sells it, but Legacy Pro does. But it works on some papers better than others. Some papers will exhibit a warmish tonal shift in the bleached areas; others remain neutral. You need to experiment because of the variables. You apply it to a print squeegeed to an upright sheet of plate glass in a sink, and need a running hose available to immediately rinse away any bleach running down from the area you're trying to bleach, lest it affect other portions of the picture. You should briefly re-fix the print when you're done bleaching, then re-wash it as well. Selenium and gold chloride toning with GP-1 are also easy ways to enhance tonal richness, but there is generally a hue shift. Selenium can go too warm with some papers if used too long or too concentrated, while gold toning produces cold tone. They can be used in combination. Again, you need to experiment to see what you like.

[Cor]

FSA toner can increase contrast considerably by deepening the blacks at the cost of a colour shift depending on the belaching agent used.

best,

Cor

[Bernard_L]

Ilford IT-8 toner; see, e.g.:
http://www.lostlabours.co.uk/photography/formulae/toners/tonerIT8.htm

[Cor]

Ilford IT-8 toner; see, e.g.:
http://www.lostlabours.co.uk/photography/formulae/toners/tonerIT8.htm

Interesting, a word of warning for those not that experienced on chemistry: (potassium) dichromate isn't very nice stuff to work with..do some research and if you still want (and can get it !) take proper and thorough precautions. I do wonder ift less harmfull bleaches (such Farmers of CupperSulphate, although not very nice also) will give the same results..probably another colour shift.

Best,

Cor

[esearing]

+1 for IT8 bleach/redevelop - or you can use pyrocat at double strength but will shift color to brown. any bleach will work but the dichromate bleaches harden the emulsion and tan it which gives that sharper look. If small print just scan, adjust, and have new negative made from the digital file.

[Eric Woodbury]

I would not risk an only print to chemicals. You may increase contrast, but at the peril of other problems. Re-photograph the image or scan so you can do your alterations without peril to the entire image. If that doesn't work, screw in a brighter bulb.