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  1. #21
    zsas's Avatar
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    Think I might have won my own MacGyver challenge.....

    $3.42 for a piece of 3x3 piece of glass.....I've a glass cutter, just need to do the darkroom-penny-paper-test:
    http://www.dickblick.com/items/34958-2983/
    Andy

  2. #22
    JimO's Avatar
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    disqualified?

    isn't that a bit incestuous - winning your own contest?!?!?

    jvo

  3. #23
    zsas's Avatar
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    Ok some updates. Blick didn't sell that red glass at the store but they sold red glass paint made by Pebeo. I bought some thinking after I painted the glass it would be darkroom safe. Well no dice, the red #04 and red#05 failed the penny test, as well as a mixture of reds #04 & #05:



    The paint was cheap $6 a bottle so it was worth a try.

    I give up....gonna just use my 63mm lens on my enlarger and the under lens holder. Then I will have more room under there....

    Thanks all for the brainstorms
    Andy

  4. #24
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    Do another penny test with the hole blocked with cardboard. You might find that light is leaking from elsewhere on your enlarger.

    And give some rubylith a go. It costs way less than that paint you just tested.

  5. #25

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    I don't see why a #25 red filter would not work. I've checked the spectral sensitivity of Ilford MG paper (which should be fairly representative of most, if not all, VC papers); it seems to be insensitive to wavelengths above about 550-600 nm (see the Ilford pdf http://www.ilfordphoto.com/Webfiles/...0200232336.pdf )

    A quick check of my B+W filter catalog shows that the 091 filter (#25) cuts pretty sharply and does not transmit anything below 600 nm (the cutoff seems to be at about 625 nm).

    Get a good quality #25 red filter and cut it down to size and Bob's your uncle.

    Best,

    Doremus

  6. #26
    zsas's Avatar
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    Poly- good points. This is an intra head filter (Leitz V35). I measured the temp of the light path where the red filter would go and it was 200F (per an old meat thermometer). I don't think (could be wrong) Rubylith is safe in a 200F+ enlarger head. I searched Roscolux and the red Rosco can go to 220F...that seems too close for me (ie fire hazard). I presume Rubylith isn't heat resistant (googling did find my answer in 3 mins so I quit lookin...).

    Note that Pebeo glass paint is baked onto the glass at 325F for 40mins. That's why I knew I could get it near my enlarger head.

    In the meantime of all this, I bought an extension tube for my enlarger that allows a longer lens to be mounted, now I have a much more comfortable working space and don't mind the under lens holder. Think I'm ready to call uncle on this project and appreciate the help. Now if Rubylith can go to 250F+....well you will for sure be the MacGyver challenge winner......
    Andy

  7. #27
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    When you say you tested with a meat thermometer, my guess is that the thermometer was mostly radiatively heated by being in the light path. The filter may be less heated maybe. The rubylith I have is plastic of some sort, but 200F isn't *that* hot... Don't blame me if you burn it down though

    Anyway, rubylith is real thin. You could stick it right under the lens or slap a large sheet of it directly on your print?

  8. #28
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    One thing to be careful about with Rubylith is age and possibly also heat. Rubylith is a red lacquer layer on a clear polyester carrier film. This layer can be cut and areas removed (graphic arts and photo applications). With time the red coating gets brittle and may crack unless handled carefully.
    Richard

    Why are there no speaker jacks on a stereo camera?

  9. #29
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    What about sandwiching a piece cut from a #29 deep red Wratten gelatin filter between two microscope slides that have been cemented/taped together? Someone must make a tape that can withstand the heat and if the filter is between glass how would it burn? Might melt but with no O2, would it be possible for it to burn?

    Didn't Cibachrome filter sets include a red? What about a filter from one of those color correction viewing kits? Or, wait for it... a piece from a red welding curtain?

  10. #30
    zsas's Avatar
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    Think I quit the project, the V35 enlarger with a 63mm lens, extension tube, under lens filter - now yields 6 inches of "leg room" - tis enough for me to end this hunt for a unicorn red filter. Messing with a glass red filter, sandwiching or whatnot will not matter anymore considering I've the room I need -(pix shows ruler ontop of easel frame - 6 inches to work with ):

    Andy

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