michaelag Posted October 30, 2017 Share Posted October 30, 2017 What is photo flo? After completing all the steps of developer, fixer and perma wash, is it necessary to use photo flo? What are the benefits or disadvantages, if any, does someone have if they use photo flo? Link to comment Share on other sites More sharing options...
Sandy Vongries Posted October 30, 2017 Share Posted October 30, 2017 Reduces spotting on negatives - reduces surface tension of water so drops "flow" off negatives more readily. Cheap, easy, good idea. 1 Link to comment Share on other sites More sharing options...
john_shriver Posted October 31, 2017 Share Posted October 31, 2017 It's very very cheap and very effective. Well worth the extra step. 1 Link to comment Share on other sites More sharing options...
Alan Marcus Posted November 1, 2017 Share Posted November 1, 2017 The light sensitive goodies that comprise film are held in place using gelatin as the binder (glue). Gelatin is chosen because it is transparent, flexible, and permeable (fluids can enter and exit effortlessly). When film enters the developer, which is mainly water, the now wet gelatin swells. This this promotes the permeability. After all the steps of the process are complete, the film is air dried. During the drying stage there are perils. Residue in the form of particulate matter can remain and will blemish the film. Since the gelatin is glue-like, these particles can become imbedded. As the film dries, the gelatin shrinks back to nearly its original thickness. Now water has a surface tension that promotes beading. We are talking about water droplets that are scattered on the film’s surface. These droplets retard drying in the area beneath them. Thus the film’s shrinking rate becomes uneven. After drying is complete, the thickness of the film will be uneven if these beads were present. Worst, the area under the beads show, we call this a drying mark. These can permanently blemish the film. An ounce of prevention is worth a pound of cure. PhotoFlow is a surfactant that breaks the surface tension. A trace amount of this surfactant in the final rinse will cause residual water to sheet up and thus not bead up. This simple remedy promotes uniform film drying. 4 Link to comment Share on other sites More sharing options...
michaelag Posted November 1, 2017 Author Share Posted November 1, 2017 It's very very cheap and very effective. Well worth the extra step. Thank you! Link to comment Share on other sites More sharing options...
michaelag Posted November 1, 2017 Author Share Posted November 1, 2017 The light sensitive goodies that comprise film are held in place using gelatin as the binder (glue). Gelatin is chosen because it is transparent, flexible, and permeable (fluids can enter and exit effortlessly). When film enters the developer, which is mainly water, the now wet gelatin swells. This this promotes the permeability. After all the steps of the process are complete, the film is air dried. Thank you so much for all of that information! It really helped! During the drying stage there are perils. Residue in the form of particulate matter can remain and will blemish the film. Since the gelatin is glue-like, these particles can become imbedded. As the film dries, the gelatin shrinks back to nearly its original thickness. Now water has a surface tension that promotes beading. We are talking about water droplets that are scattered on the film’s surface. These droplets retard drying in the area beneath them. Thus the film’s shrinking rate becomes uneven. After drying is complete, the thickness of the film will be uneven if these beads were present. Worst, the area under the beads show, we call this a drying mark. These can permanently blemish the film. An ounce of prevention is worth a pound of cure. PhotoFlow is a surfactant that breaks the surface tension. A trace amount of this surfactant in the final rinse will cause residual water to sheet up and thus not bead up. This simple remedy promotes uniform film drying. Link to comment Share on other sites More sharing options...
michaelag Posted November 2, 2017 Author Share Posted November 2, 2017 Reduces spotting on negatives - reduces surface tension of water so drops "flow" off negatives more readily. Cheap, easy, good idea. Thank you! Link to comment Share on other sites More sharing options...
Sandy Vongries Posted November 2, 2017 Share Posted November 2, 2017 Thank you! You're certainly welcome, but Alan is the Man! More detail than I ever knew. 1 Link to comment Share on other sites More sharing options...
glen_h Posted November 4, 2017 Share Posted November 4, 2017 T (snip) As the film dries, the gelatin shrinks back to nearly its original thickness. (snip) I suppose the gelatin does go back to the original thickness, but the whole emulsion shrinks. White light holograms use a thick emulsion, such that the interference pattern is within the thickness, and silver is deposited in appropriate layers. But since the emulsion shrinks, the result is that the interference is with green light, instead of the original HeNe red light. 1 -- glen Link to comment Share on other sites More sharing options...
michaelag Posted November 4, 2017 Author Share Posted November 4, 2017 Thank you for the feedback!@glen_h Link to comment Share on other sites More sharing options...
michaelag Posted November 4, 2017 Author Share Posted November 4, 2017 @alan_marcuse Dear Alan, thank you so much for all these information. I appreciate it! It was very informative. Link to comment Share on other sites More sharing options...
chuck_foreman1 Posted November 11, 2017 Share Posted November 11, 2017 While on this subject... is this the same as what goes into the dishwasher.. for spotting. Sold as rinsing agent in German it is called klar spueler? Same or different chemical? Link to comment Share on other sites More sharing options...
conrad_hoffman Posted November 11, 2017 Share Posted November 11, 2017 Pretty sure it's a different chemical. I believe a water spot will actually change the grain distribution a bit at the edge of the drop and once that happens I'm not sure you can completely fix it by rewashing. Over the years I've heard all sorts of crazy reasons not to use Photo-flo or similar products, but it makes no sense. It's cheap insurance for your negs. Link to comment Share on other sites More sharing options...
rodeo_joe1 Posted November 11, 2017 Share Posted November 11, 2017 "What is photo flo?" - It's washing-up liquid without the scent or colourant added. That's all. If you use liquid detergent for your dishes then you can use that in place of photo flo. "I believe a water spot will actually change the grain distribution a bit at the edge of the drop....." - Where did that piece of misinformation come from? 'Grains' are not mobile within the gelatine matrix. To move them about you'd have to melt the gelatine, and a cold water droplet won't do that. Link to comment Share on other sites More sharing options...
Didier Lamy Posted November 11, 2017 Share Posted November 11, 2017 Practically, and taken from Photonet's forum ~10 years ago (MM Nistico / Dressler): 3 drops of Photo-Flo in 300ml of deionized water as a final wash. Excellent results. Link to comment Share on other sites More sharing options...
conrad_hoffman Posted November 11, 2017 Share Posted November 11, 2017 Photo-flo MSDS here- https://intranet.ssp.ulaval.ca/cgpc/fsss/fichiers/Photo-Flo.pdf It's mostly water, propylene glycol and a wetting agent. Though the wetting agent is similar or the same as used in various detergents, and people have used such in a pinch, it's not really recommended because the constituents of detergents vary all over the place and you can't be sure of what you're bathing your film in. As for the grain pattern, look at a dried water spot under a microscope and reach your own conclusion. Maybe it's an optical illusion, but still darn hard to fix by rewashing. Link to comment Share on other sites More sharing options...
bethe_fisher Posted November 12, 2017 Share Posted November 12, 2017 If you use liquid detergent for your dishes then you can use that in place of photo flo. Really not a good idea. The disadvantage to using soaps is that they contain dyes and fragrances which can color or leave oily droplets on film and paper. They can also increase tackiness. Then your film or paper can stick together in humid weather. One bottle of Photo-Flo can last a lifetime. Link to comment Share on other sites More sharing options...
rodeo_joe1 Posted November 12, 2017 Share Posted November 12, 2017 "As for the grain pattern, look at a dried water spot under a microscope and reach your own conclusion. Maybe it's an optical illusion, but still darn hard to fix by rewashing." - I suspect what you're seeing is a hard water deposit (limescale) and not 'grain'. Limescale will not redissolve in water alone, but a citric acid solution should dissolve it with no detriment to the gelatine or image. It would be no worse than an acid stop bath after all. Those lucky enough to live in a soft water area, or having a softened and filtered water supply, won't suffer from visible dried water spots. "The disadvantage to using soaps is that they contain dyes and fragrances which can color or leave oily droplets on film and paper." - You'd have to use a ridiculous amount of dishwashing liquid for that to happen. Compared with the additives and contaminants in many domestic water supplies - lime, phosphates, chlorination and fluorination for example - the non-detergent ingredients in dishwashing liquid are insignificant at the few parts per million caused by adding one or two drops to a gallon of water. Time was when almost any photographic shop (find one of those these days!) stocked photo flo or some brand of wetting agent. Those days are gone. So if you don't want to buy online, you're left with little choice but to use an easily obtainable and harmless substitute. Link to comment Share on other sites More sharing options...
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