Why you should use distilled water when developing film

I got a great question from a viewer (shout out to Todd). He wanted to know how important it was to use distilled water when developing film. Truth is it is very easy to get caught up in the technical. In this video I will share with you my experiences working in various darkrooms.

[@randallstewart175]

Compounding my own B&W and color chemistry for more than 35 years, I agree that distilled water is rarely critical for mixing B&W developers. On the other hand, you would use so little of it in a home darkroom that it may be good practice in any event. Where it is critical is in the post-wash finishing in general and particularly where you have hard water, as I do. Hard water usually has a lot of dissolved calcium compounds, which can deposit in visible amounts on drying film. I use distilled water to mix a final bath of Photoflo (B&W) and Photoflo plus stabilizer (color).

[@the.negative]

I agree. If you have it and can afford it, it is the best practice to use it. I guess it depends on the volume of work to be done. In moments of extreme activity I am processing hundreds of feet of film per month. In college up to 100 students would be processing film using tap water even for the rinse. I noticed that as long as the photoflo was clean and fresh water spots where not a huge problem for the most part even living in south fl where our water quality is pretty bad. However, yes whenever possible distilled water is the best option but just don't let it slow you down if you don't have access to it. cheers! Thanks for your comment.