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  1. #1
    pellicle's Avatar
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    first contact in a long time

    Hi all

    I just thought I'd post that I've done some contacting today (4x5 and 6x12 ADOX negatives) and just starting to "feel out" what I need to do and how.

    I've used Ilford RC MGIV on postcards and used a single naked lamp 15 watt bulb at 70cm above the paper.

    "ideal" exposure seems to be too high intensity with times at about 2 seconds (I'm timing by 1 one-thousand 2 one-thousand counting).

    My plan is to next make a 'can' (to use a stage lighting term) to house the bulb and hold a filter (I'll then do some better timings with a stouffer wedge) and compare densitometery of the print to that of the negative (using an Espon 3200 flatbed scanner).

    My settings at present are:

    2 seconds naked bulb @ 70cm seems to yield a good print
    from a "wide range" negative.

    developing time around 30seconds in Dektol.

    I think that's short, so I'm keen to get advice as to how to do better on my next run. I very much like the contrasts I obtained (with no filtration on the MG paper) using this method, but clearly lower intensity would be better to enable longer exposure and hence more accuracy in the paper exposure.

    I'll post a few images after the paper drys ... now, to lunch!
    Theory: you understand why it should work but it doesn't
    Practice: it works but you have no idea how
    Here theory and practice meet, things don't work and I don't know why
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  2. #2
    Jerevan's Avatar
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    Your times seems quite short, I think. Here's a few ideas:

    Find a lower wattage bulb (I know I've found 7 watt bulbs), more distance between negative and bulb, make some sort of contraption with a ND filter to lower the output of light. Or use an enlarger if you have one and stop down the lens.
    “Do your work, then step back. The only path to serenity.” - Lao Tzu

  3. #3
    pellicle's Avatar
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    Ok ... here's a quick scan of the contact print.



    postcard is larger (longer) than the 4x5 neg and (if you click on the image above) you can (just) see base fog in the edges of the negative.

    Hopefully the can will reduce the amount of light coming from the source lamp to allow me exposures of (say) 10 seconds. I'd like to target something like that figure to allow more accurate timing of my exposure.

    Perhaps I'll need a lower wattage lamp too ...
    Theory: you understand why it should work but it doesn't
    Practice: it works but you have no idea how
    Here theory and practice meet, things don't work and I don't know why
    Homepages: here Blog: here

  4. #4

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    There are two challenges, as I see it, that you need to control with your current setup. One is contrast, the other, speed.

    Because the color temperature of household incandescent lamps is much warmer than enlarging lamps, your prints will be lower in contrast than if you had exposed them to unfiltered light under the enlarger. You can compensate with higher grade variable contrast filters, but you'll need to figure out a way to get the filters between the bulb and the paper with no light leaks.


    Because enlarging papers are pretty fast, you'll need to cut down the light that reaches the paper. Avoid the temptation to use an inline dimmer to do this. Reducing the voltage to the lamp will not only reduce the output, but will lower the color temperature of the lamp even more. Again, lower color temperature = lower contrast with variable contrast papers.

    Possible solutions:
    [LIST][*]Switch from using enlarging speed variable contrast papers to graded contact speed papers. Both challenges addressed with a single solution. Contact papers these days are rare, but can be found.[*]Rig up a can with something similar to a grid spot and somewhere to place variable contrast filters. Then move it further away from the paper.
    Frank Schifano

  5. #5
    Vaughn's Avatar
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    Possibilities...

    Lower wattage lightbulb, greater distance from bulb to paper, and graded photopapers (but may not be available in postcard papers) -- as previously suggested.
    Neutral density filter -- one or two layers of smoky glass from glass shop...or even stretched-out pantyhose.

    Your 30 sec development time in Dektol is very short...try about 90 seconds to allow fuller development and even development (plus the longer times will make it easier to be consistant)...but the print you show does have a wonderful feel to it. A greater amount of development will probably cool the print down some, also. One can dilute the Dektol to get similar results with longer development times.

    Vaughn
    At least with LF landscape, a bad day of photography can still be a good day of exercise.

  6. #6
    pellicle's Avatar
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    folks

    thanks for the suggestions. I'm particularly interested to learn (what should have been obvious) about the effect of bulb colour temperature on RC papers. No wonder I could never get my enlarger prints to seem like my contacts years ago!

    hah

    live and (hopefully) learn

    ;-)
    Theory: you understand why it should work but it doesn't
    Practice: it works but you have no idea how
    Here theory and practice meet, things don't work and I don't know why
    Homepages: here Blog: here

  7. #7

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    The scanned print you show(if it is accurate) looks like you have very eneven development. This is expected with a 30 second time in Dektol. It also looks underdeveloped and flat. Could be the scan and many of us could tell a lot more looking at the real print.

    A lot lower wattage light. Or, put it under the enlarger and stop the lens down to cut light. Develop in Dektol for 90 seconds to two minutes. Don't pull it out before at least a minute and a half so you get the full development. Without full development of the print you won't know what is available at your exposure times.



 

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