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


----- Original Message ----- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Thursday, June 22, 2006 5:17 PM
Subject: [pure-silver] Re: Suggestions needed from the real experts here



----- Original Message ----- From: "Mark Blackwell" <markb1958@xxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Thursday, June 22, 2006 8:34 AM
Subject: [pure-silver] Re: Suggestions needed from the real experts here


Yes I sure it is, but that for this batch isn't really an option. I called Kodak this morning. For those interested for Tri X its 10% and for T Max its 5%. Took about 2 mins off and we will see on the contrast. I knew that there was a general rule of thumb, but couldn't remember what it was.

When I print them we will see but the negs at least look workable.

Is this developing time? If so, its way off. The change in time for a given change in contrast varies with the film and is less for T-Max than conventional grain films but, on average, its around 25% to 33% reduction for a one paper grade difference in contrast. This is equivalent to about 3/4 stop speed to maintain equal densities. To push or pull film the difference is a little greater. Again, it varies with the film but for conventional films, and most, but not all, developers its about 1.4X the time for pushing or about 0.7x for pulling. A 5 or 10 per cent change in time will have very little effect on either contrast or equivalent speed.
OTOH, Tri-X has probably more than ten stops of overexposure latitude so 2 stops with normal contrast development will still give you perfectly good tone rendition in the print. It will just take longer to expose the prints.

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
Thanks for the help Richard. Next time I might just develop normally and test that out too. In fact sometime soon I might do it on purpose to see what happens I am sure it won't be the last time the dummy behind the viewfinder makes a mistake. LOL A drop in contrast might actually help this particular subject, but a higher contrast paper is an option if needed. I ended up using recommended development time x .80 for the Tri X and x .90 for a role of T Max that was also done the same way per kodak recommendation. Even if it was bad advise, its worth knowing that too.

One thing I will say that I was a bit surprised at these days. First the Kodak site had a phone number to call with a question. Second someone answered the phone promptly, politely and answered my question. No long waits. Only one or two menu items to get to a person. I like a lot of different bw films, but I am going to buy a lot more Kodak because of the fact that they took my call and answered a question. 

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