U of S | Mailing List Archive | alt-photo-process-l | RE: Gum tonal range and linear response

RE: Gum tonal range and linear response

Thanks Marek,
Will stick with post-flash since you do it that way. OTOH, thinking again post-flash and pre-flash could be well different, since after exposure the emulsion becomes relatively more darkened under the thinnest part of the negative, therefore post-flash will be even more proportional; more in the highlights which were not darkened after the negative exposure and less in shadows which were slightly darkened in the negative exposure.
Ah, you do it when bleach development only... Thinking on it makes things more clear; bleach development can be harsh to highlights it not controlled well (I have ruined few layers by overbleaching before), therefore by doing the flash exposure you are practically building a safety shield. Not a coincidence that I thought post-flash could be nice for use with layers that are going to be hand-manipulated then.

From: Marek Matusz [mailto:marekmatusz@hotmail.com]
Sent: Tuesday, October 13, 2009 3:28 PM
To: alt-photo-process-l@usask.ca
Subject: RE: Gum tonal range and linear response

My print flash (I use post exposure flash, and have no idea if pre-flash is the same) exposure is typically 3-4 seconds under a typical bank ov UV lights. Negative exposure is 2 minutes, but could be as long as 3 minutes for negatives printed on transparencies with almost no base density. Exposures are much longer for pictorico based negatives.
When flashing the print I almast always use chlorox bleach development, or it would take forever t develop.