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  1. #21

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    Thank you F4user, yes I'd looked at that page a day or so past and that makes me think the information on the B&H website is in error regarding safelight for this product. The B&H site says OC safelight and I don't thing that is yellow-green, more of a brownish-amber if I recall correctly. Did you notice the last part of the second paragraph? "Be carefull with prints after they have been exposed to see that no futher exposure takes place" This almost sounds like they are saying 'after exposure processing should be done in total darkness.' I have always been told that exposed but unprocessed paper is more sensitive to fogging than unexposed paper right out of the box.

    At this time it looks like I can get by with the 11w bulb about 4 feet from the work surface. It looks good at least up to 5 minutes exposure. Last night I ran a preflash time test and will expose that paper today to see if I can cut the excessive contrast with paper negatives.

    I think eventually I'll order some Arista grade #2 RC paper from Freestyle and test it. This is the paper used by Joe Van Cleave in his excellant tutorials both here and on U-tube. I'd like to get the paper negative down to a standard procedure that is repeatable.

    Then there is always the possibility of just buying some real, 100 ISO B&W 4X5 film. There has to be a first time for everything.

  2. #22

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    Quote Originally Posted by F4user View Post
    paper is sensitive purple and yellow that mean red and blue and yellow.
    red safelight is not a good choice because the paper is sensitive to magenta and magenta is not monochromatic like light, magenta is red and blue.
    i think some kind of orange can be a choice for LED safelight, between red and yellow posible to be a gap in paper sensitivity. No idea if green could be a choice for safelight, tests or sensitivity curve could reveal that.
    if you want low contrast use yellow filter, if you want high contrast use red filter, blue spectrum is there as any paper have.

    Variable contrast is a balance between red and yellow light.
    I won't get into whether Magenta has a wavelength all of its own, but I would like to read more about paper being sensitive to it, as well as "Variable contrast is a balance between red and yellow light".
    Dichroic filters remove wavelengths of light; Specifically Magenta removes green and yellow removes blue. If white light is not used as a start, and only red and yellow light are used then VC papers (being sensitive to green and blue in everything I have read) won't be much exposed at all.
    Perhaps Oriental papers have a different chemistry than other VC papers
    "There are a great many things I am in doubt about at the moment, and I should consider myself favoured if you would kindly enlighten me. Signed, Doubtful, off to Canada." (BJP 1914).

    Regards
    Bill

  3. #23

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    Agree with blue-green balance of other orthochromatic variable contrast papers.
    Bellow is a picture with spectral response of another Oriental paper and wrongly I asume 550 nm is yellow. Yellow is 580 nm centered and graphic below have a slight shift of middle peak to reds.
    Topic starter have not clear say what paper is involved.
    This is the reason for my statement.
    Click image for larger version. 

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    Last edited by F4user; 06-21-2014 at 04:10 PM. Click to view previous post history.

  4. #24

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    So I'm mulling over this whole thread eh? So I sit down and pour a cold one, and as I'm sipping at my beer I start looking at the bottle.

    Brown bottle. Kinda amber when you hold it up to the light though. And I start to think, (beer sometimes does that to you) and so I go looking for the LED flashlight and my roll of duct tape. (Also known as "the handyman's secret weapon" for all you Red Green fans).

    So I tape the flashlight, a 24 LED model, to the side of the beer bottle, a 22oz. size, using the tape to seal off leaks of white light. And I set it in the space between the towel bar and the wall, reflecting off the ceiling. It was bright enough to see by but didn't fog that Oriental paper, at least not at 5 minutes.

    Might make a good emergency safelight. The 3 AA batteries that power the flashlight will last about 3~4 hours and I could always wire in a mini plug socket and power it off 3 'C' cells in a seperate holder.

    Now don't start in on me about spectral response and all that other science guy stuff. I practice empirical photography if you know what I mean.
    Last edited by pen s; 06-23-2014 at 12:14 AM. Click to view previous post history.

  5. #25
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    Quote Originally Posted by pen s View Post
    beer bottle
    Wow! This is what I call "look outside of the box" Nice!

  6. #26

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    Like.
    All my life I improvised.

    For scientific details about beer bottle { beer safety and ... possible foggy vision :-) } spectrum read this:
    http://www.edenfoods.com/articles/vi...rticles_id=181

    Beer bottle seems to have ~600 nm peak but quite large spectrum.

    LE
    Why bother with batteries ? .. why you don't use universal 5V ( 2.5 W ) aka USB socket ? computer or charger.
    Or cheap "night light" directly in mains socket with a bottle over it.
    Last edited by F4user; 06-23-2014 at 10:26 AM. Click to view previous post history.

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