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Sunday 7 October 2012

Paper fixing faults.


This post will be short, a sort of quick guide to paper fixing faults. They are listed in no particular order.
This picture shows the fix is exhausted

         Brownish areas: fix exhausted.
 
         Print becomes yellow after a while: Was not fixed for long enough and    or  washed for to short a time.
 
         Burnt out highlights: acid fix not diluted to the right strength. Left in the fix for to long. Not timed properly.
 
         Brownish spots, Lilac round the edges: Stop bath exhausted, incomplete fixing, forgotten to wash or use stop after the developer.
 
The blue stain shows that the stop is exhausted.
         Yellowish fog over the entire paper surface: Exhausted fix, developer contaminated fix, little or no agitation while fixing.

 

It is not unusual to be caught out by some of these faults. Even when you have years of experience.

Sunday 30 September 2012

Alternative way to check your fix is still fresh.


Here are two simple and easy ways of checking that the fix is not exhausted. The bottom line is if in doubt, throw it out.

  1. Take a drop of fix and place it on some blue litmus paper, if it turns red the fix is still active, if the paper remains blue it is exhausted. Rapid acting fixes by their nature will get exhausted more quickly than an ordinary one. When fixing paper you may expect to get thirty to forty 18 x 24 cm ( 8”x 10”) sheets per litre.
  2. Take ten ml of fix and add ten drops of potassium iodide solution to the measuring jar and stir. If the milky solution does not clear after it has been shaken then the fix is exhausted and a new batch should be made up. If it clears the fix is OK to use. Make up your Potassium iodide solution from two point five grams of powder and add a thousand ml of water and mix. This method does not apply to rapid fixes.

These methods will work for your film fixes as well. But the milk test you do for film will not work with paper as you cannot see this stage with paper.