Just an idle thought....

Discussion in 'Color: Film, Paper, and Chemistry' started by Blighty, Nov 20, 2004.

  1. Blighty

    Blighty Subscriber

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    Some years ago, I thought I'd try my hand at colour printing. As it happens, I never got round to doing so. But something has always puzzled me. When it comes to printing, why must the filtration be adjusted for each individual negative. Surely, the filtration would be the same for different subjects taken in broadly the same type of light. Obviously one would have to filter out major colour casts from let's say a tungsten light source. But otherwise, once a suitable filtration had been found for the neg/paper/light source/chemistry combination, would this not apply to the remaining negs on the film.
    Regards (at the risk of sounding really thick), BLIGHTY.
     
  2. Ed Sukach

    Ed Sukach Member

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    You don't sound thick, at all, to me.

    There are a number of factors affecting color balance: the color temperature of the lighting is one, and probably the most significant. There will be variations due to processing - the age of the chemicals, the composition of the water used to mix them,... I couldn't begin to list them all ... I think the phase of the moon, whether Saturn was in Aquarius ... might have something to do with it all.

    Frame-to-frame variations are less severe, however, even the positioning of the model in a mixed lighting situation can result in a different color balance, for example.

    Normally, in the first frame I take, I'll have the model hold a gray card; from that I'll get a usable reference for analysis. From there, It all depends on the eye and taste, and perfectionism of the photographer - in this regard, it is no different than working in black and white.
     
  3. rbarker

    rbarker Member

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    Although it has been years since I did color printing, I'd agree with Ed's assessment of color-balance variations that might be encountered within a given roll. That is to say, individual shots on the roll might have been exposed under wildly different light, and may be exposed differently. Additionally, as I recall, each batch of paper will have a slightly different base filtration, which may be further affected by the batch of chemicals. Enlarger light-source variations, which could also affect filtration for individual prints, can usually be eliminated with voltage stabilization.

    If you're doing anything "creative" with the lighting or exposure, it's always a good idea to tell the printer not to adjust from their base filtration. Otherwise, they'll try to "fix" your "errors".
     
  4. Tom Duffy

    Tom Duffy Member

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    two other things that effect filtration are:
    1. the density of the negative
    2. the color casts caused by the things that light bounces off.

    1. keeping your exposure constant under the same light (read that, don't use autoexposure) will keep your printing filtration constant.
    2. take a portrait with much of your light bouncing off grass and you'll have to correct to get good skin tones, move ten feet onto a sidewalk and you'll have a significant filtration change, even though the sunlight has remained constant.

    Take care,
    Tom
     
  5. Jorge

    Jorge Inactive

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    I started doing color printing, many, many years ago. One of the things I did (since most of my shots were sun lit outside images) was to use the first frame to take a picture of a gray card. When I was ready to print I would then adjust the filtration for that film roll to the one giving me a gray card. 9 time out of 10 I was able to just print the entire roll with the same filtration.
     
  6. Blighty

    Blighty Subscriber

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    Thanks all,
    I understand that one might alter the filtration for each individual neg, but does not colour neg record its image in basically the same way as reversal film? my point being that we are unable to effect any post exposure changes to reversal film (and we still get good results!). I guess what I'm trying to say in a very roundabout way is: can one apply a single filtration to a whole film or is altering the filtration an absolute necessity and not just an aesthetic exercise (a bit of tweaking at the edges, if you like!). Before anyone jumps on me, I must add that I'm an advocate of neither method; it's just a rogue thought that keeps popping into my head at inopportune moments and keeping me awake at work. Regards, BLIGHTY
     
  7. Ed Sukach

    Ed Sukach Member

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    Can one... Yes.

    Is this an absolute necessity ... No.

    ... and just not an aesthetic exercise ...

    ??? I'd be interested in hearing a consensus on this one. There is very little in photography that is an "absolute necessity" and is therefore not an "aesthetic exercise". Of course, anyone CAN print at any level of quality - or "integrity" as far as a duplication of "what is actual". Transparencies are usually "off" a bit ... but I think there is a greater acceptance of deviations there than there is in color printing.

    The perfectionist, working with transparencies, will employ the "Decamired" system, where combinations of filters for color correction, in concert with a Color Temperature meter are used. Takes a *LOT* of filter$, and Color Temperature meters are not cheap - nor really useful other than in this application.
     
  8. rbarker

    rbarker Member

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    To control the output, control the input. That is to say, precision in exposure and color temperature control simplifies the printing process.
     
  9. 127

    127 Member

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    Colour vision is a funny thing...

    Here's my take on the subject (not necessarily correct, but some basis in fact).

    Transparancies are viewed by projection. In this case you're in a dark room, and the only bright thing is the projected slide. You brain handle different colour temperature variations by simply filtering out the dominant colour cast. You know that a banana is yellow, so when you see it under coloured light, your brain adjusts everything back to make the banana yellow. This would mean that slides can be quite a way off, and your brain does the colour correction for you.

    On the other hand prints are viewed in reflected light, where you are surrounded by "other" things. So now you have a banana on your desk, next to the picture. Your brain adjusts everything for the light in the room where you are (ie the banana looks yellow, reguardles of whether it's in light from the window, or from a bulb). Any deviation from neutral in the print will be MUCH more noticable than the slide, as you have external references to compare it to. The banana in the print isn't the same colour as the banana on your desk (or worse the white wall IS the same colour as the banana!).

    Ian
     
  10. Nick Zentena

    Nick Zentena Member

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    When I first started printing colour I would make a "perfect" print for each and every film. I would then write in my little black book so much yellow. So much magenta. F/stop and time. Assuming the negative I wanted to print was well exposed in daylight then the numbers out of the book would give me a good enough 8x10. When I say good enough I mean better then any machine print I've ever seen. If the exposure was off then things would need to be adjusted. Printing different sizes required adjustments to.

    Now I've got a colorstar 3000 and I let it do all the thinking. Often the settings it chooses are around what my perfect print would be. Rarely varying by very much. The prints I make with the analyzer are better IMHO. The little box adjusts exposure so I can crop to whatever size I want. OTOH it can be fooled at times but I blame that on me.

    If you're producing very good negatives then it's possible to bang out prints with never changing the enlarger settings. They won't be the "best" possible print for each and every negative but they won't be horrible. I guess the machine prints are made with averaging. The idea of making a perfect print and then using it's setting is I guess sort of like averaging.
     
  11. Ed Sukach

    Ed Sukach Member

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    No kidding!! I use one of those, too... in fact, it's the one piece of gear I consider to be indispensible.

    I would have gone off the deep end, long ago, without it ,... and probably would have abandoned color printing altogether without it.

    It still helps to THINK, though.
     
  12. Nick Zentena

    Nick Zentena Member

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    Yup thinking is good-). I still need to program a channel for white. I'm wondering if I can just change the density by two stops on my base settings? Right now it's keeping me sane with trying lith printing. With 6+ minute developer times test strips would drive me crazy.
     
  13. Ed Sukach

    Ed Sukach Member

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    Hmmm. I'm not sure that would work. Could you create a channel for - in the case of "negative white" - infinite density in magenta, yellow or cyan .. and infinite density overall? Conversely, in "positive white" there would be NO density in all... ?

    I have channels set for - Color; Agfacolor 100 Exposed with Dynalites - developed with Tetenal C41, and printed on Ilfocolor developed in Tetenal RA-4 - using a gray card for reference; Agfacolor 400 - otherwise the same processing and printing as previous; another channel using "Fair Caucasian Skin", instead of a gray card; Another - "Gray card in Daylight" - and so on.

    I'll do a test strip before each "session". Interesting to see the "chemistry batch - to batch" variations, the stability or lack of it, over time or in lot-to-lot variations of paper --

    I've done a few "Painting with Light" images, where the model is illuminated solely by light from a transparency projected through a Hasselblad PCP80. The technical aspects of all this are complex: the lamp in the projector has a color temperature of something like 3600K - and I'm using Daylight (5500K) film - but all bets would be off anyway, considering the changes to the light, passing through the transparency. I've set a channel for "Fair Caucasian Skin" from a gray card held by the model, under those conditions, and analyze accordingly, using the ColorStar. The models' coloring looks natural, and the colors of the projected transparencies appear to be unaltered.

    I'm sure this would be a exercize enough to drive me up a wall without the ColorStar.
     
  14. Nick Zentena

    Nick Zentena Member

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    Some times with a print with large white areas the density is off. By eye I'd say 1/3 of a stop maybe a little more. The colours are fine but the printing is just too light. What I'm guessing is the analyzer is being fooled by the large amount of white the same way a reflective light meter might.

    I could just spot the other areas in the print more but usually the white area is the important one. The nicest thing with the analyzer is I can just expose a drum full of paper and then go process. Knowing that the final result will be right. The only two areas I'm having any problems are the white images and cross processed ones. I can't get any wierd colours out of the cross processed stuff. Stuff looks way too normal-)
     
  15. b.e.wilson

    b.e.wilson Member

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    Blightly,

    Your experience with color negatives matches mine with color negatives: color is troublesome.

    But my experience with printing color slides on Fuji Type 35 or Kodak Radiance is very different. Once the filter for the type of paper is established (it's typically 5-10 of two colors, ie. 10C5Y for my current box of Fuji Type35), then all prints are made with that filter. Of course, I change it for artistic reasons, but if I want a print to match the slide, I print it with one setting for that box of paper and find the results match quite well if I don't mess up the exposure.