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Water Quality for mixing Photo-Chemicals.

Posted: Sat May 06, 2006 9:09 am
by Keith Tapscott.
What is the difference between distilled water and deionised water? :?:

Posted: Mon May 08, 2006 11:48 am
by Digitaltruth
Hi Keith,

Hopefully someone with expert knowledge will contribute an answer, but as far as I am aware you can use distilled and deionized water interchangeably for general photographic purposes.

I believe that deionization is a less expensive process, but trace particles could still be present. These particles could matter for certain scientific purposes, but should not affect photographic solutions.

Most stores seem to carry deionized water as it is suitable to use in place of distilled water for consumer purposes, and it should be cheaper.

If anyone has more information please contribute to this thread.

Posted: Tue May 09, 2006 12:08 pm
by Fotohuis
It's indeed a matter of purity.
You have also milliQ water, made by a reverse osmose system, used for chemical analysis on HPLC (chromatography) and that kind of stuff.

Deionized water is relative cheap and easy to make with a kat-anion filter.
For photographic solutions sufficient. Under normal circumstances regular tap water can do it unless the amount of carbonates and metals is rather high.

Posted: Tue May 09, 2006 12:35 pm
by Keith Tapscott.
I was considering using distilled water or deionised water for the final rinse for film and paper processing. Deionised water is the cheaper option where I live.
Cheers.

Posted: Tue May 09, 2006 2:49 pm
by Digitaltruth
I wouldn't advise using deionized water for your wash as you are more likely to compromise the overall washing sequence without the benefit of running water.

Developers that recommend the use of distilled/deionized water in the mixing process do so to avoid any reaction with compounds often found in tap water, so once you are done with the development stage this precaution is unnecessary for normal washing procedures.

A simple inline micron filter, sold in the UK by Paterson for use with their hose system, should remove any large particles which could cause abrasions or damage to film. Unfiltered wash water may contain limescale deposits or rust from pipework/tanks which can scratch the emulsion, but these particles should be too small to cause damage to paper. Other professional filtration solutions are also available for fitting to your pipework.