U of S | Mailing List Archive | alt-photo-process-l | Re: was Miracle size for gum now tonal range

Re: was Miracle size for gum now tonal range

hi marek,
sorry, i can't offer these test strips either.
i only tested the saturated dichromate (~25%) and 1/5th of the strength (5%) at double exposure.
since i was going for maximum contrast for shadow exposures.

i don't know if anyone else experienced the abrupt end of the curve in the highlights, but for me it looks like that there is a practical end to the linearity of the process, caused by movement in the water, which can never be exactly repeatable.

also i think i've seen that small highlights in dark areas take longer to clear than bigger bright areas. a bit something like a chain reaction, one particle of gum going off and takes the next one with it.
did anyone else ever see this?


Marek Matusz schrieb:
SO actually 3 test strips should be compared.

case one 1x dichromate 1x exposure (your usual working scenario), it will
require shorter development

case two: 1x dichromate 2x exposure

case 3: 2x dichromate 1x exposure

I have done these and can not find the dfifference between cases 2 and 3,
now of course case one will show shot scale, because we have learned to
underexpose gum with thin negatives

WOuld somebody show me test prints of cases 2 and 3 showing any

I actually ruined my set by leaving them a bit longer for development and
then forgetting about them for a day, so I need to make another set for
show and tell.