U of S | Mailing List Archive | alt-photo-process-l | Re: How many gum layers (Re: ferri sesquichlorati)

Re: How many gum layers (Re: ferri sesquichlorati)

Hi Katherine,

Whatever works for you is the way to go.


In a message dated 10/25/06 10:50:56 AM, kthayer@pacifier.com writes:

>  " Otherwise, why not just start with an image, invert it and make 
> a negative of any unknown density without a curve and keep fiddling 
> with it until you get what you want in the print."
> Best Wishes,
> Mark Nelson

Well, indeed, why not.   Like Keith, this is exactly my approach and 
as Keith says, it works fine.  And as Chris showed last week, it 
works good for her too.  Her tricolor gum made from inverted uncurved 
channels was cyan-biased, but that's not a function of the curves, 
that's a function of the  selectiion of pigment concentration of the 
three pigments in relation to each other.  So I guess my answer to 
Mark's question "why not?" is,  beats me!  Seems like a perfectly 
reasonable approach to me.

But since Charles posted the link for ChartThrob yesterday, I've been 
playing around with generating curves some myself, and like Keith, I 
have to say, so far I like the "no curve" approach better too.

Recently, Mark, you said that a beginner could save a lot of time, 
money, and materials by investing in a system for generating curves, 
or better yet, two systems.   At the time, that didn't make sense to 
me, because the time and materials you "waste" in the beginning 
learning to print gum are "wasted" in the process of learning to 
print gum, not in the process of generating negatives, and you still 
have to learn how to print gum, no matter how you generate your 
negatives. So I'm not sure how it would make any difference.   And 
besides, the way gum works, there's very little waste; there's almost 
no print that can't be salvaged; pigment stain is the one exception, 
and curves or no curves don't have any bearing on pigment stain.   
But I didn't think there was any point in arguing further, so I let 
that thread die without saying so.

But now, after an evening of printing value templates,  I have to say 
I think the savings are in the other direction; you save more 
materials by printing gum. At least when you're actually printing 
images, you have a print to work with and do something with, and 
chances are you can do something with it, even if you didn't get it 
"right" on the first printing.  But a template of value patches is 
just a template of value patches.  And if I was really going to do 
this, I'd have to do it for every single different pigment I ever 
use, at every concentration I use it at, at every environmental 
condition (humidity, particularly).... I would be doing nothing but 
printing templates for the rest of my life, and there's not a thing 
you can do with the stupid things, except generate curves.  Talk 
about waste of materials!  I'd rather be printing gum.

I can't say yet whether the resulting curves would be an improvement 
over the uncurved negatives; I'm not even there yet.  Will report in 
due time with a comparison.