gum curve testing
I figured I would never grasp the concept of curves or how to use them unless I did some testing on my own. Now that I've done that, I'm still not totally clear, but at least I have a starting point to refer to. What I did was download a couple of curves, as I really didn't have a clue what to shoot for. One was designed specifically for gum printing, but I noticed later that it was supposed to be used for a color separated image, and I was just making one neg, so that might be why it didn't print very well. The other curve I downloaded was from Dan Burkholder's site, and was designed for platinum, but optimized for my printer type and media. Then for fun I created a 3rd curve, sort of a halfway between the other 2 curves, and I called this one 'whatever'. The thing that baffles me the most about curves is how when applied they make a perfectly good image look really awful on screen...! If anyone is interested in my results they are here: http://lavatop.com/gum_curve_test/ and I welcome all comments! The top 4 images are how the image looked onscreen (very close to how they print on my inkjet), and the bottom 4 images are the scanned gum prints. Remember, I'm still a beginner (how long do I get to call myself that?) so the gum prints are a bit bumpy...I haven't mastered my brushing technique yet. I also took a brush to the development to help it along as it was taking so long, but I tried to brush them all equally to be scientific about it :) Is 30 minutes a normal development time? Looking at the printed step wedges, I'd say the platinum curve was the winner here for range of grays (good job, Dan!) However, I don't see any difference between 90 and 100%. But then these are all just one layer of lamp black. Should I go another layer or 2 before I can really decide? Also, I'm assuming that each different image I print might get a different curve...or is it really possible to design a 'one size fits all' curve optimized for my working methods? Best Regards, Laura
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