3 COLOR PRINTING BY GUM
Hmm, I can't think who that would be. Don suggested Stephen Livick, but to my recollection, Stephen Livick hasn't been that stingy with information, has he? He gave an online course in gum printing through Bostick and Sullivan several years ago (was there a fee charged for that? I don't remember) and I think his website includes an illustrated tutorial on printing tricolor gum. I've disagreed with many of the categorical pronouncements he's made about gum, but I'm not sure it would be fair to say he's not been open about his methods.
I've had a web page on tricolor gum in the works for over a year now, but I've moved twice in that time and spent considerable time between the moves looking for a house, as well as being sick a lot, so I haven't made much progress on that project; it's still sitting on the back burner. But hopefully once I get unpacked and settled and rested, I can finish that.
Here's a brief preview: the introduction to my page on achieving color accuracy will say that it's not that difficult to achieve "good-enough" color accuracy using a variety of three-pigment combinations. Our eyes and brains have a remarkable tendency to read any color representation as an accurate representation, as long as it retains the relative hue relationships and tonal relationships of the original image. If what should be green is green, if what should be blue is blue, etc, and if the tonal relationships are proportional to the original, our eyes and brains say that's a good enough representation. However, if instead of relative color accuracy, the goal is absolute color accuracy where every color in the representation is an *exact* match of the color in the original image, that's an incredibly difficult task to achieve in tricolor gum, as I discovered when I started testing different color combinations to try to find the "best" pigment combination for color accuracy. But I'll save the rest of that discussion for my web page. In the meantime, I'd refer people to handprint.com, because Bruce MacEvoy has some good insights about this which are consistent with my own observations.
Katharine
please excuse me for resurecting this thread-but i think maybe you have all missed some things
1. color separation by in camera negs or digital requires that you know what you are doing and where you are going
other wise you are re-inventing the wheel and generaly you get wheels that don't roll
any tech school training for pre-press before the desktop revolution could turn out people with the theory and knowledge
running a 60x60 0r 30x30 flatbed and haveing to turn out the negs to keep a busy commercial printer on schedual for a couple of 10 yrs will give you the practical end
remember that each 4/color needs 4 negs-cymk and each neg may need 3 exps-main, shadow flash, and highlight bump
this kind of experience is directly applicable to all so called alt process "art" photography since these processes are in fact what is in use every day in any form of printing-screen, offset, litho, gravure etc, and these were at one time what was main stream photography
so if you ask somebody who knows you might get an answer-IF YOU CAN GET DOWN ON THE GROUND AND OUT OF THE FANTASY DAYDREAMS LONG ENUF TO LISTEN
pre-press- 4/c strippers, plate makers, camera operators etc all are working all day long every day with the standardized materials that were once consumer products for the photo trade and are now available to any one who knows what to ask for-BUT NOT AT THE PHOTO STORE SINCE TIME MARCHES ON AND NEW REPLACES OLD BUT NOT CAUSE ITS BETTER
the point of this rant is that a 4 or 3 color print is a printing process and not 'photography' and color theory and its practical application is easy to get if you WORK at it BUT YOU MUST START FROM THE POINT OF SUCCESS
***get a pocket "printers pal" and the chapter on in camera color seps will start you from a proven place of success***
if you can ignore all the blahblogery that sells the software and hardware that must be updated every 6 mos you can get results from your pc that will also work
2. the inter-action of pigments with emulsion and sensitisers is so complex that if you don't start with a proven, standardized combination; or if you change anything and sub a new supplier etc you will get lost immediatly
standardization is very difficult with gum arabic
solution: DON'T USE GUM ARABIC ; OR IF YOU MUST, BUY A STANDARD COMERCIAL SOLUTION WHICH TAKES SOME OF THE VARIABILITY OUT OF THE MIX
EX: saul the coffee man, in costa rica, sells some gelatine and/or gum granules that you can mix up yourself and since he is also a world class artist you know that it will work
there are plenty of other substances that you can use instead of gum arabic and you can buy them in the 99cent store
"there are no rules in gum printing" really means that you never knew the rules and you don't have the skills and craft-any high school chemistry class will give you all the tools you need to be able to repeat success, even if you failed chemistry class
in 1976 i was the " tech" at the art dept of a college in a major university-that meant that while i taught the large format photo class, the tenured head of the photo dept got the very nice salary-so i went commercial and never looked back
i was a "commercial artist" and a"photomechanical artist" and a "commercial photographer" and i also was hung in juried shows
my day job was in the adv biz and at home i created "fine art" but now i am 100% dis-abled
please feel free to avail yourselves of my experience
vaya con dios