RA-4 in B/W chemicals

[3Dfan]

Is it possible to develop color paper in b/w chemicals. The idea here is to get b/w prints from color media without running into the problems related to the poor spectral sensitivity of b/w paper.

[Athiril]

Yes.

As to how effective it will depend upon the negative, your exposure on the paper and develop time/dilution.

[Mike Wilde]

I have read there is a party trick. Bob Mitchell I think was the guy I read about this from, but can't really recall.

Print colour in b&w developer and fix.

Later pour colur developer over the print, and watch colour form out of b&w print. The fix prior only took away the undeveloped silver. The developed silver, with it's dye couplers never bleached away are now lying there waiting to form colour as soon as the colour developer comes in contact with them. I think the print would look dark and need a bleach afterward to take the elemental silver left behind by the b&w developer away.

I have never yet tried this, but the thought is interesting.

[Photo Engineer]

Well, that will not exactly work Mike as no development takes place.

You must add peroxide to the developer to form a color image the way you describe. There are 2 others out there as well but a bit harder to do.

The thing is that there is not as much silver in each color layer in RA papers and the B&W silver image is low in contrast, so you may not like what you get if you develop a color paper in a B&W developer. The contrast and dmax will probably be too low to suit you.

PE

[Athiril]

So if you oxidise the developer, the colour couplers suck it in via the formed silver image?

[Photo Engineer]

Not really.

Peroxide is oxidized on the silver metal surface with the silver acting as a catalyst. That forms the imagewise dyes. Otherwise you get dye everywhere and the sheet will just blacken.

PE

[Athiril]

Sounds interesting, is there a general guide for the amount of peroxide? As in grocery store 3% solution will do? The strong stuff is hard to come by here.