Separation negatives for better tonlity

1

Hey guys, I’ve begun my foray into gum printing, and also have some burgeoning curiosity about tonal separations for other processes as well. I know traditionally people have used tonal separation negatives for better tonality with everything from carbon and platinum to silver printing, but I’m wondering, especially for monochrome processes, if there is still any real advantage to this, seeing as piezography is able to produce greater tonal fidelity in a single print than any other printing process. if this is the case, would there be a visible advantage on the final platinum or, say, kallitype / salt / cyano print?

in gum, where pigment dilutions can be used to create a light cyan or light magenta for example, I could see the advantage I guess. would it be better to use the curve adjustment and white/black point adjustments in PPE2, or would it still be best to linearize for each color separately and do PS curves for fine adjustments / tonal separations (I think I saw a post about this a while ago, but it was before PPE2). there’s also a recent post about gum regarding linearizing with the gum layer applied on top of platinum, and the suggestion was to control the gum more with pig/gum/dichro/exposure variables, but I’m wondering if it would work better to print 700step yellow, develop, dry, coat magenta on top of that, use the same 700step chart, print, develop, dry, then coat cyan on top of that, develop, dry, then coat black, use same 700 step chart to print, then develop, dry, done. ?

lets talk gum and separations!

thx

2

The only advantage in GUM or other process may be using different sensitivity for shadows and highlights to increase tonal fidelity and decrease grain etc. Not needed with higher quality processes like Platinum IMO.

linearization should always be done after all layers have been printed and then the measurement data should be applied to each individual curve that is used to make up the final print.

eg:

  1. Print neg 1 with curve 1 which may have totally blown HLs on purpose.
  2. Print neg 2 with curve 2 which may have totally light shadows and dark HLs on purpose.
  3. Print the 2x layer target with the two negs.
  4. Measure target and apply this measurement to each curve in the same way.

This should enable a linearization of a 2x (or 3x) multi-neg setup.

best,
Walker

3

Thanks for your reply Walker! I now understand in potential advantage of creating tonal separations, but for color separation, would you do it the same? Because you want the cyan, yellow, and magenta to all have the capacity to print the entire tonal range linearly, but directed by the CMYK separations however photoshop defines the split, not intentionally manipulating the curve to, say, just print magenta in the highlights or just cyan in the shadows, which I think would be the extent of color control using the method you described?

4

will the special CMYK gravure edition of PPE2 ever be public? would it help here?