Selective-toning negatives

[LF_rookie_to_be]

Is it possible to selectively tone b&w negatives? I would like to warm-tone dense portions of the negative to an orange-yellow tone, but avoid visible (or any) damage to the negative.

[Brian Ellis]

Why (i.e. what are you trying to accomplish by applying an orange-yellow tone to the dense portions of the negative)?

You can selenium tone a negative to increase density. And it can be done selectively depending on where those areas are on the negative (generally they need to be at the top, bottom, or side of the negative so that you can dip only a part of the negative in the toner while keeping the part that's not to be toned out of the toner). But I've never heard of applying a color toner to a b&w negative and don't offhand see what it would accomplish that couldn't be accomplished with selenium.

[bob carnie]

To get a yellowish tone on prints you need to bleach sepia, but this works first on the highlights then the shadows or dense areas of the print
So I think by the time you get to the dense area of the negative your shadow areas of the negative will be very yellow and you may have burned off some of the shadow detail or density.

I am only guessing so take my comments as that.

[LF_rookie_to_be]

Some more info that should have been in the first post. I'm thinking of toning an unsharp mask for printing transparencies on RA-4 paper reversal-processed (D-72/stop/wash+re-expose/RA-4). This is a rather finicky process where color crossover is almost a given. Having the dense areas of the mask (i.e., highlights) toned to a warmer tone, if the image requires it, might help with the convincing and pleasing color rendition of the final print, in addition to taming usually very high contrast. Can it be done properly without leaving marks/stains that could show on the print?

[Drew Wiley]

There are hypothetical ways to do it, some trickier than others. But in principle, you'd want
a tinted second mask in register but very unsharp, that is, with a plexiglas spacer in between. You could tint textured polyester sheet all kinds of ways, including art store dye
pen, or mixed dyes, but would have to test for effect since the film response is often different than visual response. Some dyes can be layered with considerable subtlety,
dependig on how you thin them.

[Drew Wiley]

I don't have much time to chat today, but I referred above to a generalized manual mask.
To render selective effect in complex shadows, you'd have to do some kind of what I call
wedge masking, selective only for shadow value at a certain D-Max. You select for this first by generating a lith mask which picks up density only in the shadows, then from this generate a registered reverse mask, and from it expose onto registered chrome film via either appropriate color filters or colorhead setting. The trick will be to acquire polyester dimensionally stable chrome sheet film, either what's left of Astia or E100G or Velvia 100F. Don't use acetate (Provia). Fairly simple in principle, a bit tricky in practice until you zero in on the exact exp values needed on that first lith mask. But this can also be a fun project
if you gravitate toward this kind of challenge.

[Drew Wiley]

Obviously, I'm making the assumption that you own a registration punch and registered
contact masking frame, and know how to use it. Otherwise, that kind of learning curve
would come first. But you could also generate a dedicated mask via digital techniques,
though registration would be tricker than the old-fashioned way.

[Drew Wiley]

Selectively coloring shadows is one of those tasks much easier to do via digital control
throughout, that is, curve adjustment etc right into a digital print. But a simpler darkroom
path than I hinted at above utilizes flashing with colored light at a certain point in the
workflow, analogous to coloring shadows in-camera using a colored diffuser and ND. I've
never been fond of this method, however, because you sacrifice some of the crispness and sharpness in the shadows.

[LF_rookie_to_be]

Drew, thanks a lot for these insights! I am currently looking at some older but very precise pin registration equipment I found locally. It was used for film animation, but can be applied to enlarging with some tweaking. I also found this document:
ftp://188.40.136.173/Informationssch...Ilfochrome.pdf
That should do for the start, until I try it in practice with a 4x5" Velvia landscape.

[Drew Wiley]

If you start out with a lith separation of the shadow values the problem will obviously be
using enough light to punch through the orange mask, which acts like a strong ND filter in
relation to the ortho (mostly blue) sensitivity of the lith film. In the past Tech Pan would
be used for this purpose, but I doubt you'll find any sheets of it nowadays (unless you raid my freezer!). There might be other high-contrast pan film sheet options out there. I once found some Euro substitute for Tech Pan.