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  1. #11

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    Agree Mark, I have the PF 8x10 model - which is more like 9x11. Can see that the larger negative size might not be flat in the center, the one I have does work for me. Seems like it was about 1/2 of the others.
    Mike C

    Rambles

  2. #12
    Ole
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    Quote Originally Posted by mark
    ...I also built one but had a lot of trouble finding springs that were tight enough. In fact I never got them right.
    One of mine was wooden springs, the others have steel, brass or similar. The wooden ones work quite well, despite being the better part of a cetury old!
    -- Ole Tjugen, Luddite Elitist
    Norway

  3. #13

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    I never thought of wood. Are they just warped pieces of hardwood?
    Technological society has succeeded in multiplying the opportunities for pleasure, but it has great difficulty in generating joy. Pope Paul VI

    So, I think the "greats" were true to their visions, once their visions no longer sucked. Ralph Barker 12/2004

  4. #14

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    Quote Originally Posted by Mongo
    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.
    Wow. His stuff is beautiful. I think this is one I'll leave to the experts rather than try to do it on the cheap (and pay in frustration later!).

    Thanks for the advice!

  5. #15

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    Quote Originally Posted by smieglitz
    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.

    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.

    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.

    What's a step wedge? Is that some sort of shim in the frame?

    Thanks for the exposure advice. It sounds like cooking carmel or roux -- needs to be taken off the stove a touch early.

  6. #16

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    A step wedge is a good thing. It is used to calibrate or measure the exposure. It has several different exposures on it representing the different levels of grey from clear base to bullet proof. I am sure someone will pipe in with a more technical explanation but I would say it would make you balcony exposure unit very nice.

    I print my POP paper outside but I am in AZ at 6500 feet with little to block the UV. My times have risen to near 15 minutes for what I think is a good negative as the sun gets lower in the sky. You will probably have that thing on the balcony for a really long time. I've been considering an exposure unit with BL bulbs. DO a search on the site for BLB to get a sense of what it would take. If you are not going to build a printing frame the exposure unit might be well over the top, but who knows.

    Good luck.
    Technological society has succeeded in multiplying the opportunities for pleasure, but it has great difficulty in generating joy. Pope Paul VI

    So, I think the "greats" were true to their visions, once their visions no longer sucked. Ralph Barker 12/2004

  7. #17
    Ole
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    Quote Originally Posted by zenrhino
    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.
    That's about right!

    Quote Originally Posted by zenrhino
    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.
    Norwegian winter sunlight is even rarer - so I keep indoors these days. I use a "growlight" which gives decent exposure in about 20 minutes for van Dykes and cyanotypes. I haven't tried ordinary fluorescent lights, since I already had the growlight

    Quote Originally Posted by zenrhino
    What's a step wedge? Is that some sort of shim in the frame?
    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!

    Quote Originally Posted by zenrhino
    Thanks for the exposure advice. It sounds like cooking carmel or roux -- needs to be taken off the stove a touch early.
    Try cyanotypes: When they look irredeemably overexposed, they should have been exposed 50% more.

    Mark - I'll get back to the wooden springs later - I'm 500km away from them right now, so it's a bit difficult to give you a decent description
    -- Ole Tjugen, Luddite Elitist
    Norway

  8. #18
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    A step wedge is a strip of film which has been manufactured so that a series of different densities is represented. You can buy them calibrated ($$$) or uncalibrated (~$9) but the uncalibrated ones work just fine. The density of step one is about 0.05 and each step progresses by about one-half stop per step. So, step 2 can be taken to be 0.20, step 3 @ 0.35 and so on until you reach step 21. Now a proper van dyke brown emulsion might print somewhere between 16-18 total steps which would represent about an 8-9 stop total exposure range (with corresponding densities of 2.40 to 2.60) depending on your emulsion mix and specific paper.

    To provide an example: step 1 should print out as the maximum density the process is capable of while perhaps step 16 would be paper white and step 15 just the lightest of gray tones. Steps 16-21 would all be white. If you increased the exposure the entire range would shift with step 1&2 maximum density but now step 16 is light gray and 17-21 paper white. This would indicate an overexposure of one step which is equal to one-half stop. You want to adjust exposure to get the maximum number of steps printed without blocking up and at the same time having the maximum density possible. This range will vary with your paper and emulsion mix.

    The true emulsion exposure range is actually pretty easy to determine with the step wedge. The tough part is adjusting your image negative exposure and processing so that it matches the contrast (exposure range) of the process you are working with. VDB is fairly high while Pt/Pd is less and normal silver printing below that. I'd rank the processes from lowest to highest negative contrast needed as: gum bichromate, silver, cyanotype, Pt/Pd, VDB, Albumen, POP, salted paper. A negative made for van dyke brownprinting really won't make a good silverprint even if a contrast #0 filter or paper is used.

    I have a few web pages showing VDB exposure test using step wedges. The urls are:

    http://my.net-link.net/~jsmigiel/ima...l/VDB_TMAX.jpg

    and

    http://my.net-link.net/~jsmigiel/ima...MX_TMY_HP5.jpg

    These tests were done because it was discovered new TMAX 100 has an UV blocking base which makes it a poor choice for printing in alternative processes like VDB. The tests compare exposures through new and old TMAX films, HP5+, and just the step wedge on paper. They also show the effect of processing and drydown with vdb (the difference between the marks for exposure [EXP] and dry print).

    As far as the exposure source, pick up some UV black light tubes that fit standard 24" fluorescent fixtures but be aware that the UV can damge your eyes so don't watch the exposure process. The Sun will also work but since it is not consistent this time of year you will need to use one of the hinged frames to check the progress of exposure. VDB is fairly fast so I doubt your exposures will be anywhere near six hours midday. My exposures with the NuArc are about 20 minutes IIRC and, 6" from UV tubes even faster. (But, the NuArc is preferred because it is so consistent and eliminates the guesswork and monitoring.)

  9. #19
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    You might want to pick up a copy of John Barnier's "Coming Into Focus." It is a good alternative process book and has a section on using step wedges for brownprints (argyrotypes maybe instead of vdb? but the info applies to all). Other good alternative process books are Schaeffer's Ansel Adams Guide book 2, Farber's Alternative Photographic Processes, and Christopher James' Handbook of Alternative Photographic Processes. And of course, the alt bible is Crawford's Keepers of Light. Each has its merits and shortfalls, but I think Barniers is the best overall in terms of explanations and imagery.

  10. #20

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    I made my own frame;
    http://www.alternativephotography.co...es/art017.html
    and wrote a little article for Malin.

    Jim
    There are only three things in life worth doing, art food and work, the order is merely alphabetical and if you can combine the first and the last ............

    ---------------------------------------------
    Toned Cyanotypes for sale
    http://www.jrbham.btinternet.co.uk/index.html

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