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Posted: Tue Jul 18, 2006 11:43 am
by Lowell Huff
Acetic acid Stop Bath has no chemical reaction with developer that will result in white specs. Aluminum dropping out of fixer hardener because it is improperly mixed, results in white specs.
Posted: Tue Jul 18, 2006 11:57 am
by Ornello
Lowell Huff wrote:Acetic acid Stop Bath has no chemical reaction with developer that will result in white specs. Aluminum dropping out of fixer hardener because it is improperly mixed, results in white specs.
Skipping the stop bath causes the fixer to deteriorate quicker. It also causes the formation of specs.
Posted: Tue Jul 18, 2006 12:13 pm
by Lowell Huff
Developer carry over does not cause fixer to deteriorate. The purpose of stop bath is to stop development.
Modern fixing formulas are buffered against pH change. That being said, acid, neutral or alkaline pH of fixers has no scientificly measureable effect on fixing. It is thio sulfate the combines with the un developed silver and as long as there is "thio" available it will fix. As the fixing solution saturates, fixing speed slows down but even a super saturated solution will continue to fix, it just takes longer.
Posted: Tue Jul 18, 2006 3:11 pm
by Ornello
Lowell Huff wrote:Developer carry over does not cause fixer to deteriorate. The purpose of stop bath is to stop development.
Modern fixing formulas are buffered against pH change. That being said, acid, neutral or alkaline pH of fixers has no scientificly measureable effect on fixing. It is thio sulfate the combines with the un developed silver and as long as there is "thio" available it will fix. As the fixing solution saturates, fixing speed slows down but even a super saturated solution will continue to fix, it just takes longer.
Carry over of developer does indeed harm the fixer.
Posted: Tue Jul 18, 2006 3:14 pm
by Lowell Huff
How does it harm fixer? What is the chemical reaction that harms fixer?
Posted: Wed Jul 19, 2006 10:03 am
by Ornello
Lowell Huff wrote:How does it harm fixer? What is the chemical reaction that harms fixer?
You can look this up in any good photo chemistry book.
Posted: Mon Jul 31, 2006 2:32 pm
by Lowell Huff
I have for years, told our customers that they did not need a stop bath if the were using our fixers because they are stop- fixes. I also have recommended for years, not using hardener.
Posted: Tue Aug 01, 2006 10:22 am
by Ornello
Lowell Huff wrote:I have for years, told our customers that they did not need a stop bath if the were using our fixers because they are stop- fixes. I also have recommended for years, not using hardener.
Use stop bath, and rapid fixer with hardener.