[pure-silver] Re: Mystery lines?
----- Original Message ----- From: "Jeffrey Thorns" <puresilver@xxxxxxxxx> 
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Friday, April 13, 2007 7:31 PM
Subject: [pure-silver] Re: Mystery lines?
Agitation was continuous and vigorous throughout development and fix - about 100 seconds for dev, 60 for fix. (RC paper). Both developer and fix were mixed fresh right before use.
I'll try it again tomorrow with twice as much developer and the same neg. If the problem disappears, I'll know not to be so tight-fisted with the dev in the future.
Marginal developer also occurs to me as the probable cause. Do the trays have any sort of grooves or high areas in them? If so, these can cause a localized increase in development. Also, its possible that there are standing waves unless the agitation pattern is random. 
  I could also be something else of course.
Usually, the development time necessary for maximum density increases as the developer becomes exhausted. While 100 seconds should be enough for RC paper when the developer is relatively fresh, it might not be enough if the stuff is spent. Also, there is some loss of developer volume as one works. Some is carried off with each print. This also suggests that the marks may be caused by some structural feature of the trays. Another thought, the minimum development time for RC will depend on whether it has incroporated developer. I don't think any of the Ilford papers do. Incorporated developer is mainly to allow the use of the paper in rapid-access machines that use an activator rather than a complete developer. When used in standard developer the developer activates the developing agent as well as developing with its own agents. The result is usually that the prints come up fast and complete development in a short time. Also, the capacity of the developer is increased. Some DI papers will develop in as little as 45 seconds although 60 seconds is usually recommended. Non-DI papers will take from 90 to 120 seconds for complete development. 

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


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