Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,333   Posts: 1,537,406   Online: 1166
      
Page 1 of 3 123 LastLast
Results 1 to 10 of 30
  1. #1
    CPorter's Avatar
    Join Date
    Feb 2004
    Location
    West KY
    Shooter
    4x5 Format
    Posts
    1,662
    Images
    24

    Unsharp Masking of Negatives?

    I recently signed up for John Sexton's newsletter mailing list and yesterday I recieved the 2007/2008 Workshop Schedule (would love to go to one someday). Any way, in the description for the "Fine Tuning The Expressive Print" workshop, there is mention of a technique for "simplified procedures that will demystify unsharp masking of negatives for local contrast control and sharpness control".

    Does anyone know what this means? I always thought "unsharp masking" was a digital manipulation. What does it mean to film/enlarging?

    Thanks
    Chuck

  2. #2
    JBrunner's Avatar
    Join Date
    Dec 2005
    Shooter
    35mm
    Posts
    6,780
    Quote Originally Posted by Chuck1 View Post
    I recently signed up for John Sexton's newsletter mailing list and yesterday I recieved the 2007/2008 Workshop Schedule (would love to go to one someday). Any way, in the description for the "Fine Tuning The Expressive Print" workshop, there is mention of a technique for "simplified procedures that will demystify unsharp masking of negatives for local contrast control and sharpness control".

    Does anyone know what this means? I always thought "unsharp masking" was a digital manipulation. What does it mean to film/enlarging?

    Thanks
    Chuck
    The term "unsharp mask" involving digital is yet another hammy grab of traditional photographic language.

    In a nutshell, he unsharp mask process involves making a positive copy of the negative through the back of the negative, registering them together, and then printing through both negative and positive on to paper. The paper needs to be exposed at or be of of higher contrast than it normally would. The effect greatly enhances the apparent acuteness of the resulting print.

  3. #3
    Jerry Basierbe's Avatar
    Join Date
    Apr 2006
    Location
    Michigan
    Shooter
    Multi Format
    Posts
    875
    Images
    36
    I believe the original intent of masking was for reducing contrast on Cibachrome prints. The process works very well for monochrome as well. It is used on negatives that are very contrasty that would require alot of dodging and burning. You print at a higher contrat level, but the dodging and burning should be much easier to do if needed.

    Jerry

  4. #4
    David A. Goldfarb's Avatar
    Join Date
    Sep 2002
    Location
    Honolulu, Hawai'i
    Shooter
    Large Format
    Posts
    17,241
    Images
    20
    Masking can be used for a number of different purposes--contrast control is one, although that can be done with a sharp mask, positive to reduce negative contrast or increase positive contrast, negative to increase negative contrast or reduce positive contrast.

    Unsharp masking improves edge contrast by superimposing an unsharp faint positive image over the negative. The unsharpness of the mask is controlled by putting layers of mylar or acetate between the original neg and the film for the mask, and the exposure when making the mask controls the contrast of the combined neg/mask sandwich. I don't have it handy at the moment, but there is a good description of unsharp masking in a special issue of _PhotoTechniques_ called something like "Mastering the Fine Black and White Print," if I remember correctly.
    flickr--http://www.flickr.com/photos/davidagoldfarb/
    Photography (not as up to date as the flickr site)--http://www.davidagoldfarb.com/photo
    Academic (Slavic and Comparative Literature)--http://www.davidagoldfarb.com

  5. #5
    Jerry Basierbe's Avatar
    Join Date
    Apr 2006
    Location
    Michigan
    Shooter
    Multi Format
    Posts
    875
    Images
    36
    Howard Bond did a couple articles in Photo Techniques on Unsharp masking. I don't know which issues.

    Jerry

  6. #6
    David A. Goldfarb's Avatar
    Join Date
    Sep 2002
    Location
    Honolulu, Hawai'i
    Shooter
    Large Format
    Posts
    17,241
    Images
    20
    It may be that they were just reprinted for the "Mastering Black and White" issue.
    flickr--http://www.flickr.com/photos/davidagoldfarb/
    Photography (not as up to date as the flickr site)--http://www.davidagoldfarb.com/photo
    Academic (Slavic and Comparative Literature)--http://www.davidagoldfarb.com

  7. #7

    Join Date
    Jan 2006
    Shooter
    Large Format
    Posts
    327
    Images
    11
    Robert Zeichner showed me some nice before-and-after prints where he used traditional unsharp masking techniques; it makes a noticeable difference. Look up Bob over on the Large Format Photography Forum if you have any questions.
    "There are two ways to avoid most trouble in life: live below your means... and within your seams."

  8. #8

    Join Date
    Nov 2007
    Shooter
    Plastic Cameras
    Posts
    1,028
    I have a copy of a 3 part article by Mark Jilg and Dennis McNutt on masking and how to make masks.

    If you would like a copy then send an email with just "masking" in the subject line and nothing else in message. Send request to:

    masking (at) visualperception (dot) net

    I'm only going to send this once in a day or two.

  9. #9
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    22,972
    Images
    65
    There are unsharp masks, contrast masks, highlight masks and color masks. All are covered in several Kodak "How To" books in the venerable series by that name. Some serve dual purposes but depending on the exact image manipulation you can zero in on just one function.

    PE

  10. #10
    Mike Wilde's Avatar
    Join Date
    Aug 2006
    Location
    Misissauaga Canada
    Shooter
    Multi Format
    Posts
    2,939
    Images
    29

    Not as tough as it sounds.

    I do have the benefit of a Colorstar analyser, which can do a reasonable job of acting as a trasnmission densitometer, so my life is a bit easier, but I also have done this before I had the gadget. It is a lot easier to do on 120 than 35mm , but both work; I imagine 4x5 would be a breeze.

    To make the mask, use the enlarger as a light source is a good start. Place the film to form the mask on the bottom, emulsion down. Place the negative to be masked on top, emulsion side up. Cover with glass to keep in contact, and register - thumb tacks into the alignment foam core or wood channel, etc. Cover the whole works with a diffuser- I use a sheet of diffusion, but a kleenex will work.

    My mask film is usually ortho - either Kodak 'fine grain positive release' (35mm), or cut down lith film (any size), so I can work by safelight. I don't usually fret about unsharp on colur prints - the colour itself usually dominates the impression of a print.

    I develop to a low contrast index ( say .3 of so), usually by inspection in a low contrast developer (very low contrast if I start with lith). Once dry, sandwich with the original in register in the enlarger, adjust paper contrast to suit, and print away.

    Howard Bond I believe did a very detailed article in late 2005 in 2 subsequent issues of Photo Techniques that puts all the math into this rather vague description, and describes how to do it with pan films - tmax 100 I believe.

Page 1 of 3 123 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin