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  1. #11
    gainer's Avatar
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    I have an easel densitometer-exposure meter with which I set exposure for printing. I built my own flasher which is tied to the enlarger head by velcro and which is on when the enlarger lamp is on and the flasher switch is on. The flasher has a simple diaghram to control light. I set the enlarger for the shadow exposure with the flasher turned off. Then I turn on the flasher and adjust it for the highlight to give the total amount of exposure that will give Zone 7 or 8. It is neither pre- nor post-flashing, but while-flashing.

    In order to work properly, the color temperature of the flashing lamp must be the same as that of the enlarger lamp. That is why I use a diaphram instead of a rheostat to control the intensity of the flashing light. This diaghram is simply two pieces of matte board with v-shaped cutouts. You can visualize how this works, I'm sure. You may need some neutral density filtration to cut down the light from the flasher. It need not be of optical quality and can be made from film.
    Gadget Gainer

  2. #12
    jstraw's Avatar
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    Hmmm...I wonder if the Zonemaster II print meter could be used to determine adjustments in the duration of the flashing exposure so that they can be consistant with the flasher at any height.

    I can determing a flashing exposure for a given paper at a given height. If I can meter that output so that the Zonemaster II indicates that this produces a given zone on it's scale, if I raise or lower the head, I'd just need to determine the changed flashing exposure duration to achieve the same zone from that new position.

    Does that make sense?

    It might also be possible, if the lattitude involved is sufficient, to just do tests for flashing exposure for each paper I use, at one or two inch increments and make a chart. Then I could just flash for the nearest charted height to the actual height.
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  3. #13
    Mark Fisher's Avatar
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    I took a piece of plexiglas and added some legs about a foot long (maybe 18 in....not home right now) that fold up. It is big enough to fit over my easel. The flasher is them placed on the plex. I made the legs as short as I could and still get even illumination. For awhile I just used the rights sized cardboard box and cut a hole in it...that worked fine too.

    I did it mostly because I am lazy and don't want to figure out flash times......btw, I am only pre-flashing, but I don't see how that would make a difference except in the time used.

    Mark

  4. #14
    jstraw's Avatar
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    Quote Originally Posted by Mark Fisher View Post
    I took a piece of plexiglas and added some legs about a foot long (maybe 18 in....not home right now) that fold up. It is big enough to fit over my easel. The flasher is them placed on the plex. I made the legs as short as I could and still get even illumination. For awhile I just used the rights sized cardboard box and cut a hole in it...that worked fine too.

    I did it mostly because I am lazy and don't want to figure out flash times......btw, I am only pre-flashing, but I don't see how that would make a difference except in the time used.

    Mark
    I like that approach!
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  5. #15
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    This may be a dumb question, but if people are mounting this device to the lensboard region (which varies each time a print is made) and having to test strip each print, why bother using the device at all? Why would you not just use the enlarger to flash the paper, especially when it is mentioned by gainer that you'd want the same color temp in the light sources?

    Tim
    If only we could pull out our brains and use only our eyes. P. Picasso

    http://www.timbowlesphotography.com

  6. #16
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    This thread caught my attention and I have been thinking about it all day trying to figure out if it is worth making or buying the flashing device. Right now I am simply using frosted mylar in the red filter holder under the lens (after taking the filter out of course). It has worked well for me for the most part as I use a general percentage of the exposure to set my flashing time. I thought this procedure would make the most sense since one is exposing with the same light temperature as the exposure for the print, so the appropriate layer in the paper is being exposed.

    I don't see how attaching the device to the lens board or enlarger head would be that overly complicated. After all most of us make prints about the same size most of the time. My enlarger (Saunders) has markings on the column, so it would be simple to just run some tests and take notes. Seems pretty easy to me. Setting the device the same distance from the paper would be the simplest way, as long as you could achieve even illumination. I am sure you will find a way that is best for you.

    Good luck


    Patrick

  7. #17

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    Quote Originally Posted by timbo10ca View Post
    This may be a dumb question, but if people are mounting this device to the lensboard region (which varies each time a print is made) and having to test strip each print, why bother using the device at all? Why would you not just use the enlarger to flash the paper, especially when it is mentioned by gainer that you'd want the same color temp in the light sources?

    Tim
    I think its partly an issue of convenience and accuracy. I dont use a dedicated flasher but plan on buying one; my current apprach of flashing without the neg in the carrier is tiresome and has led to mistakes. I've knocked the focus and misaligned the carrier so the composition goes amiss when making the proper exposure.
    I could post-flash but if I want to make several copies of one print (which is often the case) or if I dont get the first one right (which nearly always happens) then resetting the negative, refoccusing etc becomes annoying. Also, my archaic analogue timer doesnt have the same accuracy or control that a dedicated flasher would. And as I dont print with the same enlarger head height or f.stop on each print, a test strip is mandatory on each new print.

    Jstraw - I like the idea of a wall mounted swinging arm.

  8. #18
    jstraw's Avatar
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    I don't understand the importance of having the flashing exposure's color temperature match the enlarger's light source. Gainer, can you elaborate?
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  9. #19

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    I have my flasher mounted at a fixed height. It is about 300 mm (1 foot) to the side of the enlarger, so that the enlarger never shades the paper. In practice, I place the paper immediately under the flasher to flash it, before moving it to the easel.

  10. #20
    gainer's Avatar
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    Quote Originally Posted by jstraw View Post
    Hmmm...I wonder if the Zonemaster II print meter could be used to determine adjustments in the duration of the flashing exposure so that they can be consistant with the flasher at any height.

    I can determing a flashing exposure for a given paper at a given height. If I can meter that output so that the Zonemaster II indicates that this produces a given zone on it's scale, if I raise or lower the head, I'd just need to determine the changed flashing exposure duration to achieve the same zone from that new position.

    Does that make sense?

    It might also be possible, if the lattitude involved is sufficient, to just do tests for flashing exposure for each paper I use, at one or two inch increments and make a chart. Then I could just flash for the nearest charted height to the actual height.
    If your flasher has variable intensity, you can use the Zonemaster just as I do with my home made apparatus. Leave the flasher on at minimum intensity while using the Zonemaster meter to adjust Zone 1 or 2 using the enlarging lens and exposure time as you would were you not using flashing. Use the flasher intensity to adjust Zone 7 or 8 to suit the Zonemaster. Now check the shadow. You will see that the Zonemaster reading has not changed significantly. All you need is a switched outlet into which you plug both the flasher and the enlarger so that both are either on or off together.

    The best you can do by flashing is to add enough light so that the places where you want Zone 7 0r 8 are exposed just slightly more than the threshold of the printing material. Adding a certain amount of overall light will not add the same density increment to both high and low because of the logarithmic function involved. The log of 1 + 1 is 0.3 while the log of 10 + 1 is 1.04. This reasoning assumes that you want to add the minimum light to bring some detail into the highlights. If you just want to darken a certain area, you are netter off with dodging/burning.
    Gadget Gainer

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