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  1. #1

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    4x5 contacts - basic light source?

    I'm working on my first setup that will hopefully allow me to do 4x5 contacts. I'll keep it down to basics: darkness, frame, few trays and Adox or Ilford of some sort (not ready to splash on Azo just yet). My bold guess would be I'll also need a Bulb. But what kind of and how far above the frame? The basic exposure guideline to start with would be much appreciated (20sec?). I'm total newbie in this stuff (currently in transition from digital to chemical) so your patience is much appreciated. Hack I developed my first 4x5 in tray full of pyrocat just last week!

  2. #2
    TheFlyingCamera's Avatar
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    Basic exposure will vary so much by the distance you have the light source, the type and intensity of the light source, and the paper/developer combo you are using, that giving you a reasonable guess is meaningless. I do my contacts on variable contrast silver paper, using my dichro head enlarger, and I get about 30 seconds @ F22-F32 using my 135mm enlarging lens. If you were to use a bare bulb, you would probably get much shorter exposure times unless you use a low wattage bulb a fair distance from the paper. It may not make as much a difference with contact printing, but when using an enlarger, make sure that your bulb is a frosted, diffused lightbulb so you don't get the apparent pattern of the filament showing up in your image.


    Quote Originally Posted by dr__red
    I'm working on my first setup that will hopefully allow me to do 4x5 contacts. I'll keep it down to basics: darkness, frame, few trays and Adox or Ilford of some sort (not ready to splash on Azo just yet). My bold guess would be I'll also need a Bulb. But what kind of and how far above the frame? The basic exposure guideline to start with would be much appreciated (20sec?). I'm total newbie in this stuff (currently in transition from digital to chemical) so your patience is much appreciated. Hack I developed my first 4x5 in tray full of pyrocat just last week!

  3. #3
    David A. Goldfarb's Avatar
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    If you don't have an enlarger, and you're not using Azo, then your exposure time is going to be very short and possibly hard to control. I'd use something like a 15 watt bulb at least a few feet from the paper to start with.
    flickr--http://www.flickr.com/photos/davidagoldfarb/
    Photography (not as up to date as the flickr site)--http://www.davidagoldfarb.com/photo
    Academic (Slavic and Comparative Literature)--http://www.davidagoldfarb.com

  4. #4
    MattCarey's Avatar
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    I did some of this using the light bulb over my bathtub (not a very bright bulb, but neither am I!).

    The times were too short to control. I taped a piece of paper over the light bulb and got better results. This was with graded paper so I didn't worry about the contrast shifting (I believe the paper would give a more red color).

    Matt

  5. #5
    John Bartley's Avatar
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    Before I had an enlarger and before I knew about AZO, I did a few 4x5 contacts on Ilford MGRC paper. I used a 7 watt refrigerator bulb in a desktop lamp about 36" above the frame and filtered it through a light blue (as close to magenta as I could find) plastic sheet cut from a kids school report cover. With this setup I was able to stretch the exposure times to as much as 30-45 seconds, even with this fast paper.

    cheers

  6. #6
    Donald Qualls's Avatar
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    I've heard of 7W or 15W bulbs installed in coffee cans with an aperture at the open end of the can to control how much light escapes; this is then suspended at a known, repeatable distance above the contact printing frame/easel/counter. The shiny metal interior of the can will tend to cast a reasonably even light over a pretty well defined circle, and the low wattage and small aperture keep the times from being uncomfortably short (start with a hole an inch in diameter and adjust if your times are too long or too short for convenience; you can also change wattage if needed).

    Ideally, you'd want a heavily frosted bulb with no printing on the end opposite the threads, but for contact printing without a condenser it probably doesn't make much if any difference.
    Photography has always fascinated me -- as a child, simply for the magic of capturing an image onto glossy paper with a little box, but as an adult because of the unique juxtaposition of science and art -- the physics of optics, the mechanics of the camera, the chemistry of film and developer, alongside the art in seeing, composing, exposing, processing and printing.

  7. #7

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    Hmm... Now I'm thinking it might be a Good Idea (C) to use transparency viewer's cold cathode light panel to make an exposure. It is very uniform, not very bright - just might be a ticket. What do you think fellows?

  8. #8
    David A. Goldfarb's Avatar
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    It would be easy enough to test, and if it's too bright, just put sheets of paper over it to reduce output.
    flickr--http://www.flickr.com/photos/davidagoldfarb/
    Photography (not as up to date as the flickr site)--http://www.davidagoldfarb.com/photo
    Academic (Slavic and Comparative Literature)--http://www.davidagoldfarb.com

  9. #9

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    Take a look at this thread:

    http://www.apug.org/forums/forum43/19519-darkroominus-minimus.html

    and the attached picture. It's a 30w flood.

    The bullet reflector is 6" in diameter, and it's about 28" above the contact printer. If you tape a couple of sheets of tracing paper (or other translucent material) over the reflector, you can get exposures in the 15-20 second range.

    Of course, it depends on the speed of the paper you're using. I've been using some Ilford Galerie, which is pretty fast.

    Hope this helps.

    Steve
    Attached Thumbnails Attached Thumbnails DSCF0118.JPG  
    "What drives man to create is the compulsion to, just once in his life, comprehend and record the pure, unadorned, unvarnished truth. Not some of it; all of it."

    - Fred Picker

  10. #10

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    Just saw the pix of your darkroom. Bravo! I am in somewhat worse situation since my washing machine I happened to reuse for darkroom purpose is also a cutting edge device which combines washer and dryer in one piece effectively halving darkroom workspace... What was I thinking 3 years ago while buying it?? Trues though I was still stuck with 35mm E6 scanning at that very time...

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