Staining developers and film flatness

Jordan · Jul 9, 2006

Here's a potentially silly question: Staining developers (never used 'em myself, but I'm about to try Pyrocat-MC) are said to harden the gelatin in the film emulsion, presumably due to cross-linking by quinones derived from catechol or pyrogallol. Is this hardening enough to affect film curl in any way?

I ask this in an optimistic vein, thinking that mild hardening might be enough to tame the ridiculous curl of 120-format Fomapan 200.

JBrunner · Jul 9, 2006

I have never noticed one bit of difference (with curl that is) in the 120 stocks I use (Ilford, Kodak) with catechol or pyro vs. say Rodinal or Ilfosol FWIW, but I have never used Fomapan. Even if it doesn't, you will probably find other things you will enjoy about pyrogallol and pyrocatechol.

Hanging a clip on the end as it dries eliminates the little bit of curl I have had with these stocks, and if there is "potato chipping" some time in a book after cutting and sleeving solves that for me.

Justin Low · Jul 10, 2006

I developed Fomapan 100 in Pyrocat-HD, and it's still extremely curly. I left them (sleeved) in between two sheets of glass with a weight on top and they've flattened out nicely.

Incidentally, this is the same way I flatten my prints, though with an added tissue between emulsion and glass.

lowellh · Jul 10, 2006

What is the advantage of a "staining" developer on film. If it is not the stain--OK!

Dave Miller · Jul 10, 2006

lowellh said:
What is the advantage of a "staining" developer on film. If it is not the stain--OK!

But it is the stain! It lowers the contrast, and makes the negative a little easier to print from.

The old Maco IR film is like a clock spring, unlike the new Rollei branded IR film which replaces it.

gainer · Jul 10, 2006

The stain does not inherently reduce contrast. The contrast is usually higher on graded paper than on VC, but if the silver part of the image is bleached out, the stain image remains and may be printed on VC paper. Without a filter, the print is of very low contrast, but it is a positive print. If the stain image reduced contrast on VC paper, the print of the stain alone would have to be reversed to a negative image.

fhovie · Jul 10, 2006

I only use staining developers for the most part - the stain is a benefit as well as the tanning of the emulsion - None of this replaces the responsibility of the photographer to take control of his densities. Exposure, development processes, and the consideration of film choice need to be adjusted to take the contrast in the scene and record it to the paper you use. Stain is not a magic bullit.

Staining developers and film flatness

Jordan

JBrunner

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Justin Low

lowellh

Dave Miller

gainer

fhovie

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