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Processing for permanence 

Introduction: Photography can be so familiar to us that we rarely stop to think about the relevance of the permanence of our images. While some photographers may argue that there is little need to take care with the processing of Black and White photographs there is also an argument that photographers have a special responsibility to make sure their pictures are as stable as the means permits. One reason for this is that we can make images to be passed down through many generations but there is also another one that relates to the environment. As artists, do we have a responsibility to use the earth's resources as effectively as we can? 

Generally, processing for permanence does not require any different methods or additional steps in the process other than those normally used; CAREFUL, SYSTEMATIC WORK IS THE KEYNOTE. One aspect of making prints for permanence is the use of Fibre based paper.

STABILIZED PRINTS: In some kinds of photographic work (like newspapers ) the stability of prints is not important: they are discarded immediately after use. These prints are referred to as STABLE PRINTS. This means the silver halide is converted to compounds that are only temporarily stable. This process means that the photographer pays little attention to times, temperatures, the condition of chemicals and the methods; only a short stop, fix and wash time are used as there is often some urgency to just get an image. Negatives on the other hand should ALWAYS be fixed and washed properly. 

PERMANENT PRINTS: These prints are processed to a level that will allow them to survive for about a life-time without showing signs of age. Generally this process involves following the manufacturers basic specifications. Fixing for the correct time in a fresh solution of fixer followed by the recommended washing time. 

OPTIMUM STABILITY : Photographs intended for long term keeping should be processed for optimum stability. These prints are refereed to as ARCHIVAL PRINTS. This should not be taken to imply that they can not be harmed, but that they have been processed for optimum permanence. This is the process that is used to make "Fine Art Prints".

CAUSES OF PRINT DETERIORATION : Apart for inappropriate storage and handling , there are two main causes of print ageing that relate to processing. The first is insufficient fixing and the second is insufficient washing.

FIXING: The purpose of the fixer is to dissolve all the undeveloped light sensitive halides left on the emulsion that were not turned to metallic silver. During the process, by-products of this reaction form in the fixer as complex silver compounds. As more prints are fixed in the bath, the saturation of these silver compounds becomes greater and when the concentration reaches a certain critical level, some relatively insoluble silver compounds are formed. The stability of prints and negatives, is impaired by traces of these complex silver compounds (products of the fixing reaction) and can remain in the material due to a shortened fixing time or an excess of silver compounds in the fixer, a condition that exists when a fixing bath has been used beyond its useful capacity. THESE COMPOUNDS CANNOT BE REMOVED BY WASHING! As the concentration of silver in the fixer increases, so does the time required for complete fixing of the print. This means that you should test your fixer frequently to make sure that they have not reached a critical level of these compounds.

CORRECT FIXING: There are many different ideas and methods about correctly fixing prints. As we have seen earlier, whatever method is used it is essential that ALL the undeveloped silver halides in the emulsion must be dissolved by the fixer so that the silver compounds formed in the process can be removed from the material by washing. 

AGITATION: As in development, one of the most common fault in fixing is often not the fixer itself, but making sure that fresh chemical can reach ALL parts of the print. It is not enough to throw a print or a whole heap of prints in the fixer and wait for the suggested time. The fixer can only do its job if it reaches all parts of the print for the required time, and fresh chemical is moved across the surface during the processing time. The effect of poor agitation is seen as a stained patch in the centre or edge of the print where the chemical did not reach.

SINGLE BATH FIXING

Prints can be fixed successfully using a single bath but you must be very careful with your methods. I use this method when I have limited sink space to work in. In this case it is wise to use a stop bath as this prevents the carry over of developer (which is an alkaline) into the fixer. The stop bath should be mixed as follows:

KODAK STOP BATH SB 1

Water.................................... 1.0 litre

28% Acetic Acid........................... 48ml

(28% acetic acid is made from 3 parts of glacial acid with 8 parts of water.)

It is important to remember that Glacial Acetic Acid freezes at a much higher temperature than water (12 degrees) and should be stored in a diluted form.

As successive sheets of photographic paper are placed into the fixer, the quantity of silver in the fixer builds up. The recommended number of 8x10 prints per gallon of fixer is about thirty, although this will vary according to the density of the prints.