Process Panel
This article is reproduced by kind permission of Phil Bard http://film-and-darkroom-user.org.uk...el_hdr_new.jpg Make Your Own Processing Panel If you have a few simple hand tools, you can make this great little darkroom accessory. Used properly, it will enable you to process 4x5 sheet film without scratches or detectable mottling. I swear by mine. For years I have developed TMax emulsions by interleaving them by hand in trays, finding it to be the only way to avoid the mottling caused by using film hangers. Then I came across the idea for this ingenious device, which I call the Processing Panel. Assembly took just a couple of hours and it only required a few quick tests to determine development time and agitation patterns. Since then I have used it to produce flawless negatives with great success. By the way, here's a procedure you can use to find out if your current processing method is causing mottling:
Evaluation: Any irregularities in the density of the gray in the first print are due to unevenness in the enlarger's light source. Check again for dirt on the optics. Otherwise think seriously about upgrading your enlarger. You will never be able to get open skies even in prints with this type of problem, no matter how good your processing technique. Unevenness in the second negative is mottling caused by your agitation pattern or development hardware. Do yourself a big favor: get out the tools, get down to Home Depot and make yourself up a Processing Panel BEFORE YOU PROCESS ANOTHER NEGATIVE. You will thank yourself later... How To Make the Panel Buy the following materials:
This is what the panel looks like: Here's how to assemble it:
You can use this panel in an 8x10"; tray provided it's one that's wide enough to get your finger around the panel when submerged. I discard my developer after one use so I avoid 11x14" trays as it wastes too much chemistry (actually I get two runs out of one batch of solution). I've found that a CESCO tray works fine, PATERSON trays are too small. The presoak, stop and fixer trays can be 11x14" as these chemicals are reusable. You need to fill the developer tray almost full so that when the panel is lifted for agitation it DOES NOT come out of the solution. This will cause mottling. 64 ounces of developer works fine for me. Placing the undeveloped film in the panel takes some practice. Make sure that the emulsion side is up when doing so, and handle it by the edges. I find that buckling it SLIGHTLY will allow it to slip under the screw heads. Practice on scrap sheets. You should do your own tests for agitation and development times. What works for me is this:
Handling film is quite easy with the Processing Panel, you can even wash it this way if you want. Dry the panel thoroughly between sessions, water tends to accumulate under the screw heads, making it difficult to get dry film in place. Let me know how it works for you. And congratulations! You're on the way to the perfect negative. Now all you have to do is shoot them... (C)Phil Bard |
It seems to me that this design has a great deal of merit. It may even be possible to lean the unit on edge to allow the film to dry in-situ.
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Presumably if the base sheet was threaded then the back nuts could be dispensed with and the bolts could be trimmed off flush thereby reducing the amount of fluid required in the tray.
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