Re: 2 tricolor gums
Keith, if you want a print on aluminum that is identical to the original image, why not just put the sheet of aluminum into an inkjet printer (using whatever prep people have worked out for printing inkjet on aluminum; I'm sure people do this) and print it? No muss, no fuss, a perfect print every time. :--)
Unsolicited advice re curves:
I'll pass on this advice that a fellow photographer gave me, when I was spending a lot of time working to understand the whole phenonemon of curves. He asked me why I was doing that, and I tried to explain the rationale for why people were telling me I should be using curves for gum, and he broke in and said, "but that doesn't make any sense. Why are YOU doing this? Is there something you want to change about what you're doing? Because I don't think there's anything you should change about the way you print gum. Your gum prints are like nothing else on earth. Why would you want to try to make them look like any other photograph? Is this really what you want to do?" He said, "If it ain't broke, don't fix it." Just sayin,' FWIW.
His advice didn't deter me from going on and finishing the exploration I was on, because while I wasn't really interested in changing anything about how I print gum, I was interested in the whole curves phenomenon and wanted to understand it, wanted to understand how it works, how it applies to gum printing, why people were so convinced it was God's gift to gum printers, what it can do and what it can't do, and so forth. I asked Michael Koch-Schulte a lot of really dumb questions and printed color arrays and calibration charts and generated curves for dozens of different pigments and pigment concentrations until I can truly say that I understand all that, and can write about curves and gum from a comfortable base of knowledge and experience. So I think all the time I spent was worth it from that aspect.
The only reason to use a different curve than what you're using now is if there's something wrong with the tonality of your prints, if you need to distribute the tones differently. I don't see that; the tonality of your prints (these and others I've seen as well) looks very good to me except for here, maybe a little blown out highlights at the top of the torso, which is easily enough fixed by changing the density range of the negative or by manipulating the exposure (back in the old days when I was doing a great lot of gum printing, long before all this curves hysteria arose, I would simply "burn in" an area like that for a few seconds to give it some tone there, rather than messing around with the negative. And now I remember these are unoiled paper negatives, so it's hardly surprising that the print is a little contrasty in spots.
You say you have a long ways to go; I say you're almost there. A little change in the pigment concentrations, and I think you'll have it nailed. My 2cents worth, if that,
On Nov 19, 2008, at 9:01 AM, Keith Gerling wrote:
Here are two recent gumphotos on gessoed aluminum using non-oiled paper negatives. http://www.gumphoto.com/gumboth.jpg http://www.gumphoto.com/gum1.jpg http://www.gumphoto.com/gum2.jpg I made these two pictures at the same time using the same emulsions and exposure times. The only difference is that the gesso/pumice mix for the aluminum substrate was was made at different times. I guess this shows that consistency is important. The layers were applied yellow, magenta, cyan, using a muted pallete (too muted - I'll make the second round more colorful). The gesso for the 2nd print was more absorbent, causing the development time to triple. The red layer just did not seem to want to clear. This experiment has been very frustrating. These are actually the 8th and 9th attempts. With the first attempts, using curves (two sets: one was very similar to the straight lines provided early this week by Chris, the other more curvey that I came up with using PDN) the right leg of the dancer totally disappeared. On these attempts, using no curves, the leg is at least visible) For the record, here is the original shot. http://www.gumphoto.com/original.jpg I would like for the gum to be identical. It looks like I have quite a ways to go!