RE: Gum tonal range and linear response
Marek, I think you had mentioned that before, but I somehow forgot about it... Thanks again for another useful tip; I will definitely try this if I come to a situation that calls it. I use digital negatives (but the curve is from cyanotype) and I usually don't have any problem with highlights, only occasional underexposure which is pseudo-fixed by developing less (I don't like this but will do it if I need). May switch to give short flash exposures in future prints; I can certainly use more robust (but not stubborn!) layers in development, especially if I plan to intervene by hand. What is your upper and lower limits for flash exposure? (Please include info about the base exposure too, to let me compare.) Thanks again & regards, Loris. ________________________________ From: Marek Matusz [mailto:marekmatusz@hotmail.com] Sent: Tuesday, October 13, 2009 4:43 AM To: alt-photo-process-l@usask.ca Subject: RE: Gum tonal range and linear response etienne, I just thought about the whole linear/non-linear response of gum and now I think that my method of exposing gum for some time and then flasing it with straigh UL light (no negative) for a short time period (seconds) which results in a very nice extension of highlight detail, is an old-fashined way of curving otherwise linear Stouffer step tablet. Maybe somebody saavy in Potoshop could work out a curve that corresponds to this physical manipulation. It really works miracles to reveal highlight detail of dense negatives. It adds little exposure to shadows that have already been exposed a lot, but changes highliths a lot, since it adds a significant exposure there. Great for those palladium negatives that you never though could be printed in gum. Marek
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