That works for you? A final distilled water rinse does not prevent water spots for me. I need to use some surfactant.
I substituted a good rinse with distilled water after normal washing, and was much happier.
It's difficult to know if everybody in this discussion is talking about the same product because 'Photoflo' has become a generic word and is quicker to type than 'wetting agent'. But not all wetting agents are the same and some are better than others, or should that be some work better in different types of water? For example I used Fotospeed wetting agent for many years with no problems at all in a soft water area, but I moved to a hard water area and got drying stains. I changed to Ilford Ilfotol and have not had a streak or drying mark since. In fact I went to college in the same soft water area and we never used a wetting agent, nor were we taught we needed one, and nobody got drying streaks or stains.The water on the surface is what causes streaking on negatives, not the water that has soaked in to the emulsion being released later through drying. The emulsion dries from the outside surface so it would be unlikely to contribute to spots and streaking.
One more thing - this is sort of correct, but not entirely. What's correct is that the water that evaporates from the film surface can leave calcium scale there, resulting in spots/marks. We're all familiar with these. However, a gelatin emulsion drying unevenly (e.g. due to a droplet hanging on to the emulsion, causing this site to dry out much slower than its surroundings) can also result in drying marks. The notable difference between the former and the latter marks, from a practical perspective, is that the calcium spots can be removed. The marks from uneven drying are generally permanent.The water on the surface is what causes streaking on negatives, not the water that has soaked in to the emulsion being released later through drying.
When I was in college 55 years ago, I took a few photography classes for fun. My professor harped on NOT putting Photoflow solution in the roll film developing tank with reels of film. He claimed that it damaged the reels and cans because it leaves a residue that is hard to remove. This is also a problem with the film itself, that this solution will remain in the emulsion and cause future problems. He taught that this should only be a surface treatment. So he taught removing the film from the developing reels and swishing it through the photoflow soution a single time with the photoflow in a bowl in the see-sawing motion that once was using from developing film at home. I've continued this treatment method, which makes me favor bulk loading 35mm rolls 30 exposures long since my arms aren't long enough to handle 36 exposure length rolls.
In recent years, I see on Youtube nobody is doing it this way and nobody talks about this. They just dump some photoflow in their developing tanks with water and film in them, and swish it around for a while. I think my professor was right. The water on the surface is what causes streaking on negatives, not the water that has soaked in to the emulsion being released later through drying. The emulsion dries from the outside surface so it would be unlikely to contribute to spots and streaking. Photoflow solution can't be very good for the long term storage of negatives. I've never had any spots or streaks on my negatives when done our way, so it works for me. I may be OCD, but this bothers me enough to talk about.
Comments and discussions are very welcome on this topic.
One more thing - this is sort of correct, but not entirely. What's correct is that the water that evaporates from the film surface can leave calcium scale there, resulting in spots/marks. We're all familiar with these. However, a gelatin emulsion drying unevenly (e.g. due to a droplet hanging on to the emulsion, causing this site to dry out much slower than its surroundings) can also result in drying marks. The notable difference between the former and the latter marks, from a practical perspective, is that the calcium spots can be removed. The marks from uneven drying are generally permanent.
A wetting agent or surfactant will protect especially against differential drying marks. It also helps to an extent against calcium spots, but in my experience this isn't complete/certain protection regardless if the product is used according to the manufacturer's guidelines. The main determinant of drying marks that consist of deposited material is (wait for it...) the presence of such materials in the water on the film (brilliant eh!) For this reason, many people find that a final bath using demineralized water, perhaps in combination with wiping the film (although opinions are very divided on this) is needed to get perfectly clean negatives. This is one of those areas in darkroom work where you have to figure out what works best for you in your specific situation, with your materials and preferences.
Try cleaning/coating plastic reels with a carpenters pencil by running the pencil around the grooves .
It's the best invention since draught/tap Guinness.
it mightbe but most-likely-mightnotbeRe: the final rinse in demineralized water. It makes sense, although I use my regular filtered darkroom supply. Would water gathered in a dehumidifier tank be useful? I have lots of that!
dehumidifier
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