OA safelight For Multigrade Paper?

Discussion in 'B&W: Film, Paper, Chemistry' started by aoresteen, Jan 25, 2014.

  1. aoresteen

    aoresteen Subscriber

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    Is Kodak OA filter ok for use with Ilford Multigrade IV papers ?

    Thanks!
     
  2. michael_r

    michael_r Subscriber

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    Probably not a good idea. OA is a greenish-yellow, which probably passes too much green light (Multigrade papers are sensitive to blue and green light). See page 1 in the Ilford link below showing the spectral sensitivity of the paper, and the Kodak link below showing the spectral characteristics of safelight filters (in the graphs which follow the summary, OA is the first graph - and you can see that transmittance extends into the green wavelengths, well below the cut-off suggested by Ilford).

    That being said, no safelight is 100% safe for indefinite amounts of exposure so the best thing to do - always - when you either try a different safelight filter or a new paper, is to conduct a proper safelight tests to determine your safe time. See Kodak and online resources for the proper safelight test procedure.

    http://www.ilfordphoto.com/Webfiles/2013116121925810.pdf

    http://www.kodak.com/global/en/professional/support/techPubs/ti0845/ti0845.pdf
     
  3. Tom1956

    Tom1956 Inactive

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    I think all the OA was good for was the old Velox paper. Useless nowadays.
     
  4. michael_r

    michael_r Subscriber

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    In general you have more flexibility with graded papers because they are mostly blue-sensitive rather than blue and green sensitive. OA was also described as being ok with contact papers, but contact papers are typically significantly slower than enlarging papers. So all things considered, variable contrast enlarging papers require the most care in safelighting.
     
  5. RalphLambrecht

    RalphLambrecht Subscriber

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    HERE IS a simple trick to check.take a new or usedCDorDVDwith you into the darkroom.hold it upand bend it slightlyuntil you see a reflection of your safelight in it. bend it enough to break the reflection into a rainbow pattern,similar to using a prism.now,the content of green and blue radiation becomes clearly visible.there should be very little of it,otherwise,switch to a deep red safelight;less comfortable for your eyes,but safer for the paper.
    :wink:
     
  6. Barry Kirsten

    Barry Kirsten Member

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    Kodak no. 13 filter is recommended for VC and panchromatic papers.
     
  7. David Brown

    David Brown Subscriber

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  8. aoresteen

    aoresteen Subscriber

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    Thanks all!
     
  9. fotch

    fotch Member

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    The info from Kodak Safelight Data sheet states differently. The #13 is for color negative papers, panchromatic black-and-white papers.

    The OC is for contact and enlarging papers
     
  10. fotch

    fotch Member

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    Welcome Barry Kirsten to APUG!
     
  11. Barry Kirsten

    Barry Kirsten Member

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    While the OC (amber) filter may be safe for some papers, many prefer the extra safety of a no. 13 (dark amber), Ilford 902 (light brown) or 1A (red), for VC papers which are more susceptible to safelight fogging. Having said that, I used an OC for years without harm, but at a distance of at least 2 metres.

    Thanks for the welcome, fotch. :smile:
     
  12. Doremus Scudder

    Doremus Scudder Member

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    Just for the record here is the Ilford recommendation from the Multigrade tech sheet:

    "Safelight recommendations
    MULTIGRADE IV FB Fiber can be used with most
    common safelights for black and white papers. The
    ILFORD safelights are especially recommended as
    they generally allow darkrooms to be brighter, but
    completely safe, for MULTIGRADE IV FB Fiber and
    many black and white papers.
    ILFORD safelights are the ILFORD SL1 darkroom
    safelight or the ILFORD 902 (light brown) safelight
    filter fitted in a darkroom lamp (for example, the
    ILFORD DL10 or DL20). A 15W bulb is
    recommended with these safelights.
    For direct lighting, do not expose the paper to the
    safelight for more than 4 minutes, and the distance
    between the paper and the safelight should be a
    minimum of 1.2m/4ft.
    Other safelight filters can be used, for example,
    the Kodak OC and the Agfa-Gevaert G7, or the
    Philips PF710 safelamp."


    ...and the Kodak blurb on the OA and OC filters:

    "OA Greenish yellow (for) Black-and-white contact and duplicating materials, projection films (i.e. NOT green-sensitive materials)
    OC Light amber Contact and enlarging papers (this would work :smile: )

    Red would work too, since it has even less green than the OC.

    Here's a link to the Kodak tech pub: http://www.kodak.com/global/en/professional/support/techPubs/ti0845/ti0845.pdf

    Whatever safelights you end up with, you need to test them for safety.

    Best,

    Doremus