rbarker said:Remember, folks, the rhino is talking about Van Dyke printing here. As such, I don't think the conventional printing frames with opaque backs will work, because one (apparently) needs to be able to see the back of the paper.
rbarker said:Remember, folks, the rhino is talking about Van Dyke printing here. As such, I don't think the conventional printing frames with opaque backs will work, because one (apparently) needs to be able to see the back of the paper.
mark said:...I also built one but had a lot of trouble finding springs that were tight enough. In fact I never got them right.
Mongo said:If you search eBay for items for sale by the user "sneakykeen" you'll find beautiful contact printing frames. For some strange reason he doesn't build his 8x10 frames with hinged backs (although his larger frames always have hinged backs), but his ads will tell you everything you want to know about a properly constructed frame and his work is well worth considering.
smieglitz said:Not so. The hinged back allows one to check exposure along the way but that isn't even needed if you calibrate your process. Having an opaque back is actually desirable to block reflection and non-image exposure through the back of the paper. Black felt is often used to eliminate this reflection and also provide for a more even distribution of pressure from the springs or clamps that hold the frame pieces.
I recently picked up a NuArc 26-1K plateburner with vacuum frame and unless I tape the negative to the paper, which I won't do, as soon as the vacuum breaks the paper and negative sandwich shifts. So, checking exposure midway is not an option with this system or with a frame lacking the hinged back or with two sheets of glass clamped together.
If you have a constant exposure source (plateburner, fluorescent tubes, quartz studio lamp, etc.) you can use a step wedge and determine the exact exposure required for your paper and emulsion mix by doing a simple exposure test. (This assumes that your negative has the proper density range for that process of course.) You need to expose the test until the maximum number of steps have printed without any merger of tones. The first step should be exposed to produce the maximum density of which the paper/emulsion mix is capable. All the other steps will print out relative to that maximum density. If you have merged tones on the shadow end, your print exposure is excessive. Once you know the range and have a proper test , it is a simple matter to expose the negative to the exact exposure required. This is a very repeatable way of working and it eliminates the need for the hinged contact print frame.
With van dyke brown you will find the correct exposure looks too light by a couple steps. The print will gain several steps of density in processing and drydown. The opposite will be true of cyanotype which should be printed to the point of solarization since it will lose several steps during processing.
zenrhino said:Ok, let me go over this bit by bit since at my level of learning, this is like my trying to read Kant in 5th grade -- fascinating but not quite digestible.
zenrhino said:For exposure I was just going to set it out in the sun on the balcony. Granted, Minnesota daylight in the winter is pretty short. Will this take more than 6 hours or so to expose? My resources are pretty limited, but I do have a number of floursecent lights around the house -- mostly the kind that get put into table lamps.
As explained, it's a "test negative" with solid blocks of different densities. Very useful, but not half as fun as experimenting with "real" negatives!zenrhino said:What's a step wedge? Is that some sort of shim in the frame?
zenrhino said:Thanks for the exposure advice. It sounds like cooking carmel or roux -- needs to be taken off the stove a touch early.
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