controling saturation

Discussion in 'Alternative Processes' started by Nyarochrome100D, Jul 3, 2006.

  1. Nyarochrome100D

    Nyarochrome100D Member

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    Was there ever such darkroom technique that punched up saturation in color prints?

    Something like using special masking techniques?

    I ask because as far as I can see a lot of Photoshop techniques are based on real darkroom techniques, so maybe saturation is one of them..

    What exactly does the computer do with chanells when you increase saturation? And is there a way to do the same thing in a darkroom?
     
  2. Donald Qualls

    Donald Qualls Member

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    Saturation actually comes from video processing, I think -- in analog color video (at least with NTSC signal) you can, with a suitable "box", alter the amplitude ratio of the signals for brightness (the one that's compatible with old B&W sets) and color (the one that overlays color on the brightness signal), so as to change the resulting picture pretty continuously from completely monochrome (gray scale) to garishly oversaturated.

    The nearest I can think of that would work in a wet darkroom would be, starting from a transparency via internegative, to overexpose the negative and then compensate exposure in the print; both will tend to produce extra dye compared to normal exposures and will thus tend to slightly increase saturation -- but it's not a commonly applied control, because it requires starting from scratch with an internegative (or, if your original is a negative, making an interpositive and *then* an internegative).

    Overall, aside from changing actual products (i.e. switching from Portra 160NC to Portra 160VC), the only way I know of to affect saturation of color negative film is to increase or decrease exposure -- which has other effects besides altering saturations.
     
  3. Photo Engineer

    Photo Engineer Subscriber

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    Yes, in conventional processing there were methods to increase color saturation either through masking or by means of amplification.

    This achieved higher apparent color contrast.

    But, the idea is to reproduce the original scene so most photographic products try to reproduce just that and no more. Reversal films do just what you describe. They can make a garbage dump look like paradise, but negative films are designed to reproduce a scene accurately with as presise a color rendition as possible.

    Printing color slides onto Ilfochrome is one method of increasing the color contrast.

    If you want the entire repertoire of methods, it is an entire course in color printing and is beyond the scope of this thread.

    PE
     
  4. Nyarochrome100D

    Nyarochrome100D Member

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    Hi Photo

    I thought about this last night, and tried to think of a way to use masks to increase saturation..

    this is what I came up with:
    making 3 BW separations, and making a reversed copy of each, then printing each BW separation to a fresh piece of BW film and substracting (or adding, didn't figure out that yet) the other two reversed copies so that in the end you have 3 fresh BW layers each containing a sort of a "difference" between the layer it was supose to show and the two other layers combined.
    Would be like bustracting the other two layers from each layer of the color image
    Would that work?
     
  5. Claire Senft

    Claire Senft Member

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    Printing Velvia on Ilfochrome would be one way. Printing Kodak UC 100 on Ultra paper would be another way. Both of these are easily done.
     
  6. Photo Engineer

    Photo Engineer Subscriber

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    This is too complex.

    What you want is a high contrast mask for the image (color) you want to increase in saturation. Methods are shown in the Kodak Dye Transfer publications, but are now out of print.

    Another method is to bleach, but not fix a print, then redevelop, bleach, redevelop and bleach until you achieve the color saturation / contrast - that you want.

    The first method above can target a single color, but the second enhances overall contrast and saturation.

    There are many ways to get at this problem. Simply using the high saturation films and print materials will often satisfy your needs.

    PE
     
  7. phfitz

    phfitz Member

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    Hi there,

    " Methods are shown in the Kodak Dye Transfer publications, but are now out of print."

    They had a more detailed method in their graphic arts manuals, also out of print. Basically you make a highlight/shadow mask, for trans:

    Adjust exposure so there is no density in the mask below zone 3 on the original trans.

    Dilute the developer AND reduce the total volume of developer to force a hard shoulder on the mask by zone 7. Testing, testing, testing. Use continuous agitation or streaking is likely.

    This will produce a really strange H&D curve. The shadows use tone contrast, the mid-tones use color saturation contrast, the highlights are back to tone contrast. This will 'pump-up' the apparent color saturation while leaving the shadow details. It adds neutral density to the highlights so you'll need to dodge the shadows or burn-in the highlights.
    If the original is over-scale for the paper, it should just fall into place.

    Just a thought.
     
  8. Nyarochrome100D

    Nyarochrome100D Member

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    That's a method of GETTING high saturation images, not INCREASING saturation