I use a dish washing tub, maybe it's a 3 Gallon tub. I have one hole in the middle bottom, and three holes (about 1/16") on each side along the bottom. I put the print in face up, I and start to fill it, when it's full I turn the water off, and let it drain. This takes about 5 minutes. I do that twice before and after the Hypo Clearing Agent. The prints tends to float up, and I gently push it down. The current leaving through the bottom hole pulls it down a bit. The concept is that the water flows down and away (across) from the emulsion. The only modification I want to make is wide grid of fishing line sewn in through the sides to hold the print off the bottom.
E. On Jun 3, 2008, at 9:34 PM, Eric Nelson wrote:
I used food coloring to test my Kostiner "archival" washer years back and was disturbed when I saw how long it took to run clear, so to expedite that, I dump about 25% off the top by tilting the unit once or twice during a 1 hour wash. Also a pre-wash after hypo clearing lessens the carry over. I find them very inefficient. The only advantage to this style washer it seems is I can leave it alone as opposed to a siphon which I need to monitor to make sure the prints are shuffled. So w/the Kostiner, it's 1 hour or more washing (inefficient) but I can walk away, have dinner and come back to deal with the prints later, or 20 minutes of fairly regular monitoring w/a siphon. My prints have always tested negative for any residual fix using the "archival" washer. Eric --- Richard Knoppow <dickburk@xxxxxxxxxxxxx> wrote:====================================================================== =======================================Kodak's recommendation is that the water in the washing vessel change completely in five minutes. This is a bit misleading since a running water tank or tray changes exponentially. What is important is the rate of change at the surfaces of the paper. The emulsion washes out by diffusion, an exponential process. The rate at which the hypo leaves depends on the difference in concentration of hypo in the emulsion versus the concentration in the wash water at its surface. The greater the difference the faster the hypo diffuses into the water. Obviously, even when there is no hypo in the water, the rate will become slower as the washing progresses. If a print or film is washed in standing water the hypo will form a cloud at the surface and eventually reach approximate equilibrium where the process becomes very slow. The diffusion continues into the body of the water in the vessel so that the processes is continuous until it reaches true equalibrium but without agitation it will essentially stop at some point. The idea that hypo is heavier than water and will sink is a misunderstanding of the process. There may be some slight convexion at the surface but nothing more. The best washing is in a low volume vessel with continuous change of water at the surface, for instance, the spray washing found in many motion picture processing machines. Large volume tanks with relatively low flow rates, such as many "archival" washers, are less effective than a tray with a Kodak tray syphon in it, provided that a single print is washed so that both surfaces are exposed to the water. This is quite practica for RC paper, which also has a short wash time but may be a problem for fiber and for large quantity work. The best "archival" type washers, perhaps "vertical" washer is a better term, are those with the smallest volume and highest flow rate at the surfaces of the prints. One way of testing the flow rate of a tank or tray is to get it going and then put some vegetable dye in it. I've used the juice from canned beets. See how long it takes before the color fades to the point where it is visibly gone (again this is exponential). It should not be more than five minutes. I have a Zone VI 16x20 washer which has too low a flow rate. I use it by putting it in a bathtub and allowing it to overflow the top. I also make a practice of pulling the plug and draining it about halfway through the wash and starting over with a fresh filling. I also use a 16x20 tray (actually about 18x24) with a Kodak tray syphon. This will discharge the dye in about two minutes at a reasonable flow rate. One can also achieve good washing using the successive bath method. This is necessary were running water is not available or where fresh water is at a premium. Both Kodak and Ilford have instructions for this method. They are slightly different: Kodak recommends several successive baths of the same length while Ilford recommends baths which begin by being short and are successivly longer. This is to take advantage of the exponential rate of washing. Both are effective but the Ilford method probably uses less water. Since the support of fiber paper does not wash out by a strictly diffusion process it needs more time. The emulsion of fiber will wash out nearly as quickly as RC paper but the substrate (Baryta layer) and support take longer even when a wash aid is used. Paper and film can be tested for residual hypo by using the silver nitrate test recommended by Kodak. This consists of a solution of silver nitrate in acetic acid as a preservative. Its used in the same way as the residual silver test mentioned in an earlier post. A couple of drops are placed on the wet, but blotted off, emulsion surface and allowed to stand for about two minutes. There should be no more than a very slight yellow stain. The stain will darken with time so the examination should be made immediately. There is a method of fixing the stain so that a densitometer can be used to determine the quantity of hypo remaining. A true answer this question would require knowledge of the diffusion rate of the emulsion involved and also the rate of washing of the support of fiber paper. There are some actual rates mentioned in the literature but they are important only for very critical work. The Kodak recommendations will result in fixing and washing sufficient for good permanence. I try to avoid using the term "archival" because it is really very vague. True archival use implys that the prints or films will be stored in highly controlled conditions, certainly not displayed. We are mostly concerned with making our images in a way that is not overly sensitive to atmospheric polutants or has residual compounds contained in it which attack the image. This is not too difficult, one needs only to follow good conventional practice. The use of a sulfite wash aid will reduce both paper and film wash times by a factor of about six times. --- Richard Knoppow Los Angeles, CA, USA dickburk@xxxxxxxxxxxxxTo unsubscribe from this list, go to www.freelists.org and logon to your account (the same e-mail address and password you set-up when you subscribed,) and unsubscribe from there.====================================================================== ======================================= To unsubscribe from this list, go to www.freelists.org and logon to your account (the same e-mail address and password you set-up when you subscribed,) and unsubscribe from there.
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