[pure-silver] Re: Suggestions needed from the real experts here

  • From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
  • To: <pure-silver@xxxxxxxxxxxxx>
  • Date: Wed, 21 Jun 2006 18:05:39 -0700


----- Original Message ----- From: "Mark Blackwell" <markb1958@xxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Wednesday, June 21, 2006 5:12 PM
Subject: [pure-silver] Suggestions needed from the real experts here


Well today was just one of those days. Working today with some Tri X pro 400TX and was working with studio lights and a Minolta Flash Meter. Well somedays you just wake up dumb and today was one of them.

Yep was working with 2 cameras one set at ASA 100 while the Tri X is 400. Want to guess which ASA the flash meter was set on and the really smart one today forgot to switch when switching cameras.

Yep it looks like the Tri X got about a 2 stop over exposure. At least it will dense rather than thin negs. I thinking of cutting the development time down to compensate. Any recommendations on how much to cut it and if the explaination isn't too deep in chemistry Id appreciate it. I plan on using D 76 either straight or 1 to 1.

Thanks for all the help

Mark
You can loose nearly one stop by developing in either Kodak Microdol-X or Ilford Perceptol (they are identical). When used full strength these extra-fine-grain developers loose about 3/4 stop when compared to D-76. The results will be normal contrast negatives.
The other stop can be ignored, the negatives will simply be a little denser than usual with more shadow detail.
You can loose another stop of speed by reducing development but the contrast will be lower. For most conventional films (not tabular grain) reducing deveelopment time about 33% will reduce the negative contrast about one paper grade and loose about 3/4 stop of speed. Kodak development charts are based on a contrast index suitable for contact printing or diffusion enlarging. To print on the same grade paper on a condenser enlarger the negative contrast is reduced as above. The tone rendition is exactly the same whether the negative contrast or paper contrast is adjusted.
Most film has tremendous overexposure latitude and nearly no underexposure latitude. If you had underexposed by two stops you would be in real trouble, for 2 stops over, you will get perfectly good negatives that will take longer exposure in the enlarger.
My recommendation is to develop for your usual contrast in Microdol-X or Perceptol.
BTW, both have good tone quality and will give you very fine grain although not much of the edge effects that cause acutance. For formats larger than 35mm this makes very little difference.

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx 

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