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The problem with fixing film and paper






You might think to use the same batch of fixer for film and for the paper, after all, it's just fix right? Be warned grasshopper, it might seem to work, but it's very unwise…

You see, it's all about the silver halides and their byproducts. Isn't everything in photography! Film has around 5 times the concentration of silver halides in the emulsion than paper, and a large proportion of these are different. Because of this, when fixed, film creates a lot more dissolved byproducts*, I mean a lot more! Of these by-products silver iodide, not present in paper, is particularly difficult to fix and remove. Remember, this iodide is present in film but not paper **). These dissolved halides (not to mention dyes used in film emulsions) can ultimately get into the paper base and stain stain it or seriously reduce its archival quality

The problem is, this might not happen straight away, leaving you with a false sense of security! However, down the line it'll come back to bite you with staining/discolouration spoiling the photograph! 

So always make up two batches of fix, one specially for film and one for paper. Mark the bottles carefully and keep your fix for film separate from your fix for paper. Never fix more than the makers capacity (see the fix instructions) and, if in doubt make up a fresh batch.

Till next time, keep firing those shutters!

John


More at: pictorialplanet.com



* Post Development Processing
©Copyright 1998 by Dr. Michael J. Gudzinowicz
https://www.photo.net/discuss/threads/why-two-step-fixing-is-a-really-good-thing.93389/

** "All of our papers are coated with emulsions consisting of crystals formed from a mixture of silver chloride and silver bromide (referred to as chloro-bromo emulsions).
Our films use emulsions consisting of crystals that are a mixture of silver bromide and silver iodide (iodo-bromo emulsions)."
https://www.ilfordphoto.com/faqs/photographic-paper-faqs/

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