Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 72,521   Posts: 1,598,207   Online: 784
      
Results 1 to 9 of 9
  1. #1
    David Lyga's Avatar
    Join Date
    Nov 2007
    Location
    Philadelphia, PA USA
    Shooter
    35mm
    Posts
    1,414

    masking negatives in preparation for cropping: a difficult dilemma (in theory)

    Interesting question:

    When you wish to print only a tiny portion of a negative, say only 1/10th of the whole area, does masking the rest of that negative (so that there is then no extraneous projection of that 'waste' onto the easel) benefit the printed image in that that image retains greater contrast (because it is now not having to compete with the extra ambient light that masking has prevented)?

    It seems obvious that masking would allow this fortunate circumstance to happen. But, if you choose to print the WHOLE negative, then would that small portion (indeed, the whole print) suffer slightly from ambient lighting presented from the whole negative's projection?

    Perhaps it sounds foolish to present this as a 'dilemma', but it would be interesting to dissect whether or not that isolated small section (actually, the whole print if the whole negative is printed) would suffer as a result, and that the whole negative being printed would, thus, have to be printed to a slightly greater contrast in order to mitigate all that ambient light. Does any of this make any sense? (If not, carry this to a theoretical extreme: if you printed 1/100th of the negative, all that extraneous light from an unmasked negative would seemingly HAVE to have a slight fogging effect.) - David Lyga
    Last edited by David Lyga; 07-26-2014 at 09:58 AM. Click to view previous post history.

  2. #2

    Join Date
    Feb 2010
    Location
    Montreal, Canada
    Shooter
    Multi Format
    Posts
    5,221
    Non-image forming light should always be minimized, but in practice it shouldn't make a meaningful difference unless the negative is very thin around the desired crop area (ie a lot of light getting through) and there are surfaces for it to reflect off. It has to bounce off the easel and reflect off something else back onto the paper. If you want you can also put some black cardboard around the image area on the easel to reduce this reflection. Remember the light coming through the negative is focused, so that helps a lot.

    There will always be some amount of flare in the system too. But in his thorough testing Dr. Richard Henry (Controls in Black and White Photography) found the effect on image contrast to be negligible under most circumstances.

  3. #3
    David Lyga's Avatar
    Join Date
    Nov 2007
    Location
    Philadelphia, PA USA
    Shooter
    35mm
    Posts
    1,414
    Right, cropping is no problem. But it is interesting to note that when printing the whole image, the whole image receives slightly more fog than if only a tiny, masked portion is printed. This probably will not be noticed but, theoretically, it MUST occur (and, by definition cannot be prevented if the whole negative is being printed). - David Lyga

  4. #4
    ic-racer's Avatar
    Join Date
    Feb 2007
    Location
    Midwest USA
    Shooter
    Multi Format
    Posts
    6,478
    If you have an adjustable masking negative carrier you can easily test the effect with the blades in or out on your cropped image. In my darkroom the white light surrounding a negative can have a dramatic effect. For example printing a Minox negative with a light system designed for 35mm (and no masking) produces a dramatic decrease in contrast, so I always mask the white light around a negative. I think most advanced darkroom workers do the same. This is because many glass carriers don't mask the image, they sandwich the entire negative with surrounding light spillover.

    Click image for larger version. 

Name:	minoxcarrier.jpg 
Views:	13 
Size:	57.5 KB 
ID:	91809

  5. #5
    David Lyga's Avatar
    Join Date
    Nov 2007
    Location
    Philadelphia, PA USA
    Shooter
    35mm
    Posts
    1,414
    Yes, fog happens, but usually no one notices (unless extreme like the Minox example, ic-racer). But it is an interesting topic to discuss, or at least notice. The very image-forming light causes very slight fog overall and, whether within the camera or upon the enlarger's baseboard, it exists. Thus, there is NO theoretical possibility of attaining a totally fog-free image. Maybe I am pressing this too far but maybe others will have something to say, as well. - David Lyga

  6. #6
    ic-racer's Avatar
    Join Date
    Feb 2007
    Location
    Midwest USA
    Shooter
    Multi Format
    Posts
    6,478
    It is flare on the enlarging lens of most concern, but 'extra' image forming light bouncing off the white baseboard, hitting the wall and coming back to the paper is also possible. I'd agree that many things cause flare or fog, even going back to the careful use of a compendium shade when making the original image on film.

    So one might think the 'cropped' image has better composition than the full negative, one might also think the tonality of that important cropped central portion of the negative can be improved by reducing lens flare during printing.

  7. #7

    Join Date
    Feb 2010
    Location
    Montreal, Canada
    Shooter
    Multi Format
    Posts
    5,221
    Quote Originally Posted by David Lyga View Post
    Yes, fog happens, but usually no one notices (unless extreme like the Minox example, ic-racer). But it is an interesting topic to discuss, or at least notice. The very image-forming light causes very slight fog overall and, whether within the camera or upon the enlarger's baseboard, it exists. Thus, there is NO theoretical possibility of attaining a totally fog-free image. Maybe I am pressing this too far but maybe others will have something to say, as well. - David Lyga
    This is why sensitometric testing is done by contacting rather than projection. But excepting fairly extreme circumstances Henry's tests showed even stray light around the negative in a carrier has less of an fee than one might expect.

  8. #8

    Join Date
    Jun 2007
    Shooter
    35mm
    Posts
    1,085
    It is true that there must be some flare effect from a whole neg being printed, but if the lens is good then it would be minimal and (importantly) massively overpowered by the image-forming illumination. In any case, a neg-carrier with masking arms is pretty much standard isn't it(?), and any alternative/extra masking could be done with a simple black paper mask on top of the carrier, or around the easel.

    I suppose I'd agree that there must be a flare effect, but that it is simple to ensure that it is minimal.

  9. #9
    David Lyga's Avatar
    Join Date
    Nov 2007
    Location
    Philadelphia, PA USA
    Shooter
    35mm
    Posts
    1,414
    Quote Originally Posted by Michael R 1974 View Post
    This is why sensitometric testing is done by contacting rather than projection. But excepting fairly extreme circumstances Henry's tests showed even stray light around the negative in a carrier has less of an fee than one might expect.
    Yes, Michael, you cannot get around the fact that, for 'purists', contact printing captures ONLY the image, nothing more to compete with that ideal. Thanks. - David Lyga



 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



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