I search the archive but didn't find one. So here's the question:-
Is warm wash temperature more efficient than cool water? My running water gets around 29 degree c (84 deg f) year round. I'm thinking of shortening wash time as I believe my water soften the emulsion. Occasionally, the emulsion peels a little from the paper base. I'm using alkaline fixer if that helps.
Does anyone know of a better way (other than tapping) to dislodge bubbles from print washer's panels and print surfaces?
Thanks!
Aaron,
warmer water is more efficient, because it has more power to dissolve substances. However, there is a tradeoff in terms of what you discovered. The wamer the water, the softer the emulsion gets. It may help, if you finally put the paper a minute into cold water, but that does not help against damages during the washing process and - of course - requires cold water. The refigerator or some ice may help in the latter case.
You can safely reduce the wash time. I would suggest by 1/4 in contrast to 20-22°C and by 1/3 in contrast to 18°C.
Hi Aaron,
According to the literature, warmer water is more efficient than cooler water for washing fiber based prints. However, it is probably not very much more efficient for washing film or RC paper. Alkaline fixer washes out faster than acidic fixer. According to Ilford, the emulsion begins to soften around 86F, so you probably aren't in any danger at 84F. Aside from cooling down your wash water by placing a sealed plastic bag filled with ice into your washer, you could add hardener to your fixing solution, especially your film fixer, if your emulsion is peeling. However, you would then need to wash for a longer time, and/or use a wash aid (HCA) to neutralize the acidity.
Regarding the air bubbles that are forming on your prints, try adding a few drops of a wetting agent, such as Photo-Flo, to your print washer. Lift the prints up and down frequently while they are washing. Also, it's a good idea to clean the inside surfaces and dividers of a vertical archival print washer with a mild dishwashing detergent once in a while. That will help to reduce the bubble formation.
If you're getting emulsion peel on your prints, I'd agree that you may have too much total time in the water. All of that, however, may not be in the wash cycle. If you batch prints in a holding tray while making more prints, for example, time in the holding tray is part of the total time in water.
Rather than increasing the temperature of the wash water, I'd suggest using a hypo clearing agent, which reduces the wash time - typically from 60 minutes to 30 minutes for fiber-base prints, for example. And, keep tabs on the total time in water, including any holding tray in the darkroom.
If you're getting edge separation, where the emulsion starts to peel at the edges, the water flow may be too aggressive, and perhaps too directional. For example, I wash in a tray, and try to keep the water flow gentle and toward the center of the print, constantly shuffling prints from the bottom of the stack to the top, flipping the print each time. That physical movement also acts to dislodge any bubbles that form on the surface. You might also consider "stand" washing, where you don't use water flow for exchange, but rather dump and refill the tray at intervals that result in total exchange of the wash water about five times during the wash time. You still need to shuffle the prints with this method, so all surfaces are evenly exposed to "fresh" water.
Appreciate your kind response. I always use HCA but I'll try 1/3 reduction in wash time (that's 40 min.). Since I make 4-6 prints each session, I guess tray holding time is not too long. Ralph is right about aggressive water flow which I'm inclined to, believing it will make a better wash. I'll add Photo-Flo and disturb the prints a little for better bubble management too. Thanks so much to Thilo, Eugene & Ralph.
I'd strongly suggest using some kind of residual hypo test just to get a baseline idea of how much washing your prints need. Tests have shown that subtle differences in water pH and mineral content can have a radical, difficult to predict effect on wash times. Which is to say that no one can tell you what wash time and temperature will work, even if they're using identical materials and processes. You might get lucky and find that a short wash is all you need. If not, then you'll have to investigate other solutions.
Hi Paulr. I've read about the hypo test before, but somehow had not consider it. I shall take your suggestion. I'll do it! Thanks for the suggestion.
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