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  1. #21
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    Re the question from 127 - it doesn't matter whether you pre or post flash. The results are the same.

    Flashing adds a small, uniform amount of exposure to the entire print. In the shadows, this amount of additional exposure is trivial compared with the blast of light through the clear areas of the negative, and so the amount of increased density in the print due to flashing is negligible. But in the highlights, which are the areas of the negative with the greatest density, the incremental flashing exposure is more significant and results in a perceptable amount of increased tonality.

    Flashing is an experimental process - the amount to do depends on the amount of contrast reduction you are seeking and the way you go about doing it. It's relatively easy to get a decrease in contrast of a quarter grade or thereabouts.

    I do it using a flashing card. This is a sheet of heavy cardboard with a large (about 8x10") opening cut into it. I glued a sheet of drafting film onto the cardboard. After I have made the base exposure and done whatever burning I feel appropriate, I slip the cardboard under the enlarge and give the print an additional bit of exposure through the drafting film while jiggling the flashing card. Note that this approach does not require a second enlarger, an auxiliary light source, or that the negative be removed from the enlarger. The image-bearing light from the enlarge passes through the drafting film which acts as the mother of all diffusers, completly obliterating the image and producing instead pure light on the easel. It also absorbs quite a bit of light. I find that a flashing exposure of about 5 - 7% of the base exposure is the ballpark necessary to reduce contrast a bit and give a little texture to marginally blown out highlights.

  2. #22
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    About 20 years ago I worked in a lab making about 2,000 B&W custom prints a month with two D5's and a roller processor. For blown highlights I'd take the pre-flash diffuser I had made from the Ansel Adams design (two spaced pieces of translucent white plex/perspex, sized to slip a 75mm gel into the slot between them) and hold it against the enlarger lens. About 20% of the main exposure worked to increase highlight detail without fogging the paper. I left the negative in because I had to work quickly and it was more convenient if I needed to make a second print. One layer would have worked and given me shorter flash times, but I didn't need that extra speed and didn't want to take the pieces apart. I got the plex for free from the cut-off bin at the sales counter at Cadillac Plastics in Minneapolis.

    I didn't test for before/after differences. Hopefully Les will chime in on that.

    Lately I've been thinking about testing for the differences in flashing VC paper with blue and/or green light. I have some LEDs that should be coming on Monday so I can make myself a dimmable, switchable blue/green flashing box similar to the RH Designs flasher, running off it's own timer. There goes that patent out the window.

    Lee

    P.S. Any lawyers know if an APUG post qualifies as prior art?

  3. #23
    127
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    Quote Originally Posted by Monophoto
    Re the question from 127 - it doesn't matter whether you pre or post flash. The results are the same.
    Thats what I think - though I haven't tested it. I can't see how it could matter at all.

    HOWEVER, plenty of people swear it makes a difference (including plenty in this thread). Some of them have claimed experimental evidence, and most have far more experience than I do. I've heard it enough to wonder if there actually is anything in it, or is it simply folklore that has got passed around.

    Ian

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    Its not folklore and I could explain it in a way I think it works. However, I'm not sure if the explaination, and what terms I use, would be acceptable or at least the right description of whats happening, so I'm reluctant to do so. I can only say that after 30+ years of printing professionally, it makes a difference...not only which goes first but if you are using, pure light, or filtered light...and then which filter you are using.

  5. #25

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    Flashing notes

    I took an advanced printing workshop last fall from Howard Bond, a noted teacher and master photographer/printer. He uses Ilford paper and teaches a simple flashing technique for burned highlights. Here is information from my notes.

    Dim down small 7-1/2 watt night light bulb. This can be done with a rheostat or electrical tape over a portion of the bulb. Dim the bulb brightness down so the threshold exposure is say 10 seconds.

    Make a mask for the area you want to reduce the contrast for by cutting out the shape on a thin piece of cardboard such as the material normally furnished with enlarging paper in the wrapper. Simply put the cardboard in your easel, project the image on the cardboard, and draw a pencil line, then cut the shape with a razor blade.

    Now, mask out the area of the print that needs normal contrast treatment, and flash the problem area to 2/3 of the threshold time. Move the mask around while flashing as you do when dodging and burning to soften the edges.

    Your final exposure will yield less contrast in the highlighted area that was flashed.

    I saw this demonstrated, but haven't tried it yet. I forget whether the highlighted area should be exposed with a lower numbered filter (say 00) as was described in a post above. This is called split printing and it can be very effective in lowering contrast when burning in highlights.

    I hope this provides a starting point to give the technique a try. I believe it can be a problem solver.

  6. #26
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    Quote Originally Posted by Loren Sattler
    I took an advanced printing workshop last fall from Howard Bond, a noted teacher and master photographer/printer. He uses Ilford paper and teaches a simple flashing technique for burned highlights. Here is information from my notes.

    Dim down small 7-1/2 watt night light bulb. This can be done with a rheostat or electrical tape over a portion of the bulb. Dim the bulb brightness down so the threshold exposure is say 10 seconds.

    Make a mask for the area you want to reduce the contrast for by cutting out the shape on a thin piece of cardboard such as the material normally furnished with enlarging paper in the wrapper. Simply put the cardboard in your easel, project the image on the cardboard, and draw a pencil line, then cut the shape with a razor blade.

    Now, mask out the area of the print that needs normal contrast treatment, and flash the problem area to 2/3 of the threshold time. Move the mask around while flashing as you do when dodging and burning to soften the edges.

    Your final exposure will yield less contrast in the highlighted area that was flashed.

    I saw this demonstrated, but haven't tried it yet. I forget whether the highlighted area should be exposed with a lower numbered filter (say 00) as was described in a post above. This is called split printing and it can be very effective in lowering contrast when burning in highlights.

    I hope this provides a starting point to give the technique a try. I believe it can be a problem solver.
    What an excellent tip!
    Don Bryant

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