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  1. #1
    Seabird's Avatar
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    Masking film emulsion up or down when creating unsharp masks?

    I'm just starting to explore the world of mask-making for B&W printing purposes. My questions pertain to correct technique for creating unsharp masks.

    Fig.1 on p.257 of Ralph Lambrecht's most excellent "Way Beyond Monochrome" (Ed.2) indicates that when creating the mask (i.e. not printing) both negative and masking film are placed in a "sandwich" with both films emulsion up.

    But:

    Fig.2 in Mark Jilg and Dennis McNutt's article "Three Contrast Reduction Masks" indicates that when creating the mask both masking film and negative are placed in the "sandwich" emulsion down. Similarly, Howard Bond's article in the Jan/Feb '96 edition of "Photo Techniques" indicates emulsion down.

    In short: why the difference and does it matter?

    I appreciate that if the masking film is a thin base film (e.g. ortho-litho) used emulsion down without a spacer then the degree of "unsharpness" will be severely restricted on account of the thin base of the masking film. By contrast, placing both emulsion up means that the degree of "unsharpness" is always at least that due to the thickness of the negative base.

    Does this explain why Lambrecht (who is chiefly interested in sharpness effects) recommends emulsion up and Jilg/McNutt (who are more concerned with contrast reduction than sharpness) recommend emulsion down?

    Any other pros and cons to either approach that I'm missing? Comments appreciated and thanks in advance

    Cheers

    Carey Bird
    http://members.iinet.net.au/~cbird/index.html

  2. #2
    MarkL's Avatar
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    Yes you're correct about the differences in film orientation. Jilg and McNutt wanted to reduce contrast with no edge effects (contrast reduction mask). An unsharp mask for increasing apparent sharpness via edge effects is achieved by a bit more space between the emulsions, which makes the mask image very slightly larger.

  3. #3
    Seabird's Avatar
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    MarkL, Thanks for the confirmation.

    Best regards

    Carey Bird
    http://members.iinet.net.au/~cbird/index.html

  4. #4

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    In mask making, emulsions should always be facing. Both when making and when printing. An unsharp mask is made using a diffuser, which causes the unsharpness, but needs to be registered to the original neg. Registration is best when no space exists between the emulsions.

  5. #5
    Seabird's Avatar
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    Quote Originally Posted by Hikari View Post
    In mask making, emulsions should always be facing. Both when making and when printing...
    Hi Hikari,

    Thanks for your response.

    Sorry but I dont understand. Why should the emulsions always be facing? (This advice is contary to all the sources cited in my original post.)

    Best Regards

    Carey Bird
    http://members.iinet.net.au/~cbird/index.html

  6. #6
    Photo Engineer's Avatar
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    In the Kodak Dataguide "Color Separation and Masking" they give only one method of masking as follows:

    Light Source ------> /Original Emulsion/Base/// Diffusion Sheet .003" max optional ////Emulsion of print material/Base/

    The optional iffusion sheet is recommended for unsharp masks, but is omitted for normal masks. This is from page 39 of the manual. It goes on to show that the masks are used emulsion to base with the original closest to the lens.

    PE

  7. #7
    Seabird's Avatar
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    Quote Originally Posted by Photo Engineer View Post
    In the Kodak Dataguide "Color Separation and Masking" they give only one method of masking as follows:

    Light Source ------> /Original Emulsion/Base/// Diffusion Sheet .003" max optional ////Emulsion of print material/Base/

    The optional diffusion sheet is recommended for unsharp masks, but is omitted for normal masks. This is from page 39 of the manual...
    Hi PE,

    Thanks for replying and sharing that.

    Its interesting that Lambrecht and the Kodak guide you refer to advocate the same orientation, while Jilg & McNutt advocate the alternative - and Howard Bond has PROVEN (to my eyes) that the alternative works beautifuly. I conclude that perhaps it doesn't matter, but will have to try both and see for myself.

    Thanks again

    Carey Bird
    http://members.iinet.net.au/~cbird/index.html

  8. #8
    Photo Engineer's Avatar
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    Carey;

    It is sometimes difficult to spot changes unless you see direct side-by-side comparisons. If someone shows you a good print from a given masking method, all well and good if you are satisfied, but for real proof you need to be shown 2 prints comparing both methods out there before you can have true "proof"!

    But, use what works!

    PE

  9. #9
    rmolson's Avatar
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    masking film

    In reference to the Kodak book on color separation.The film that they normally recommended was a film designed for masking and as memory serves me used base to base.It was a very low contrast film making control of contrast in development easier And of course it was panchromatic.

  10. #10
    rmolson's Avatar
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    PS

    Opps that was emulsion of the masking film to the base of the original

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