You might want to check out the analog photography users group;
http://www.apug.org/forums/home.php
Lots of good stuff there.
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Don Sanderson wrote:
Thanks Tom, I'll have to try a roll and see what happens. Now I'm waiting for someone to respond to the question on Diafine developer. Hadn't heard of it till today, verrrrryyy in-ter-es-ting!
Don
-----Original Message----- From: Graywolf [mailto:[EMAIL PROTECTED] Sent: Tuesday, October 26, 2004 2:08 PM To: [EMAIL PROTECTED] Subject: Re: C-41 Process Black and White
Traditional B&W film has a 'S' shaped characteristic curve where the shadows are compressed together at the bottom and the highlights are compressed together at the top with an almost straight line portion in the middle. That straight line portion is where you normally fit your exposure. It is, at normal development, about 10 stops long. (If you can get a hold of a copy of the data sheet for almost any professional film they will show the characteristic curves of the film on it for different developing times. You can probably down load data sheets from Kodaks website.)
Chromogenic B&W has a much longer straight line portion something in the order of 15 stops (do to separate layers of differing speed instead of differing colors). That is why you can use different ASA's with the same development. You are just taking the 7 stops of your print from higher or lower along that straight line portion of the curve.
Chromogenic films do print much better on regular B&W paper but the negatives tend to be fairly low contrast and require that you use a high contrast filter and develop the paper for about the maximum time the paper will allow (2-3 minutes with most paper).
I used to use XP1 extensively. Supposedly the only difference was XP2 is optimized for C-41 development while XP1 was optimized for its own developer but could be developed in C-41. From what I have seen XP1 developed in XP1 developer was sightly better than XP2 in C-41, but XP2 in C-41 is better than XP1 was.
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Don Sanderson wrote:
Hi Collin,
Don't understand "toe or shoulder", is this steep
highlight/shadow curve?
Don
-----Original Message----- From: Collin Brendemuehl [mailto:[EMAIL PROTECTED] Sent: Tuesday, October 26, 2004 9:41 AM To: [EMAIL PROTECTED] Subject: Re: C-41 Process Black and White
It's a mixed bag.
Some labs handle it well and give you nice results. Tones are really soft but even. So it works well for many portrait situations and the results are very predictable. A good thing. And using the ubiquitous C-41 process is a very convenient feature.
Not much of a toe or shoulder, IIRC. (Someone correct me if I'm wrong on that.)
Sincerely,
C. Brendemuehl -------------------------------- 'Politics is supposed to be the second oldest profession. I have come to realize that it bears a very close resemblance to the first.' Ronald Reagan
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