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  1. #1

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    Neutral colour film?

    I'd like some suggestions for colour film to make images of colour charts. They will be shot in lighting where the colour temperature is tightly controlled. I assume I need something that is relatively neutral/even in its spectral response, and not too saturated. Format is 120, and I'm looking for both transparency and negative.

    The choices for transparency seem to be rather limited these days, and I was thinking of Provia 100f. Any others? For negatives, I have some Reala - is this a good bet?

    Also, am I right in thinking that the colour temperature to aim for is 5500K?

  2. #2
    heterolysis's Avatar
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    Can't say I know much about colour temperature, but Reala seems to be one of the more balanced print films to my eye.

  3. #3

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    If they are to be shot "in lighting where the colour temperature is tightly controlled" then you probably need to find out to what standard this is set and check the filtration needed between your film(s) expected colour-balance and that of the lighting. Better to get this perfectly correct in camera than to try to compensate afterwards somehow.

    What film you choose will also depend on how much light there is and what you are photographing in it - are the colour-charts made of artificial paint, ink, natural pigments, a wide-range of colours vs a limited set, or ??

    What will be the final output that you require? RA4 prints, B+W prints, projected-slides ? Transparency-films are a bit of an orphan child for reproduction these days, especially as there are so few left, and you might want to stick with neg if you need prints at the end of the process.

  4. #4

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    Quote Originally Posted by MartinP View Post
    If they are to be shot "in lighting where the colour temperature is tightly controlled" then you probably need to find out to what standard this is set and check the filtration needed between your film(s) expected colour-balance and that of the lighting. Better to get this perfectly correct in camera than to try to compensate afterwards somehow.
    I have two choices of lighting - 5300K and 6500K. I'm assuming at the moment that colour film is balanced for 5500K, and have been working out the required filtration for the colour temperatures available. My calculations suggest that I need mired shifts of +28 or -7 depending on the source I use, which probably depends on which colour temperature adjustment filter I can find most easily/cheaply. Either filter (82 or 81B) will get me to a mired shift of about 3 from the 5500K ideal. I should also have access to a colour temperature meter to check the actual output.


    What film you choose will also depend on how much light there is and what you are photographing in it - are the colour-charts made of artificial paint, ink, natural pigments, a wide-range of colours vs a limited set, or ??
    Four 24" 18W fluorescent tubes with a high frequency ballast and brightness control, arranged in a square around the target. It's been a while since I last measured the output from such a setup, but I reckon something like f8 at a sensible (reciprocity-free) shutter speed will be no problem. The target is a ColorChecker Passport, opened at the colour patches (Gretag-Macbeth style grid) and warm/cool/grey patches. I don't know what the patches are made of, but would assume pigments of some sort.


    What will be the final output that you require? RA4 prints, B+W prints, projected-slides ? Transparency-films are a bit of an orphan child for reproduction these days, especially as there are so few left, and you might want to stick with neg if you need prints at the end of the process.
    No output - they are for comparison with other films (Velvia 50 and 100f, and Ektar 100).

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    Comprehensive replies! Yes, as you obviously know very well, the 'standard' daylight is 5500K, so you just have a small adjustment to make. We can assume that you aren't talking about household fluorescent tubes (in case anyone tried to use those after reading your description), and also that the colour patches won't contain odd dyes, brighteners or pigments as they are intended to be for reproduction testing purposes.

    You seem to be making a determined effort to check what is going on in your comparison - inevitably I'm curious about what you will be doing with the information! The only thing not mentioned so far is the processing but I doubt that you are planning to use an out-of-control lab for your work. How will you compare the Ektar and the transparency films, via an RA4 print (reflected versus transmitted light, oops)?

  6. #6
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    I would suggest that Portra 160 is better than Reala, even if only for the finer grain. They are both pretty neutral but they emphasise different things (Fuji has nicer green separation for example). I shoot a lot of Reala so I have nothing against it, but if accuracy of reproduction is the order of the day then get the Portra 160. But Reala would be OK if that's what you have on hand; it has no major vices except coarser grain.

    Provia 100F (RDPIII) is about all you've got in chromes now that Astia is gone. Neutral but the contrast is quite high.

    Beware the fluorescent bulbs unless you know their CRI is high (absolutely no less than 90, i.e. without problematic holes or spikes in the spectrum). Having the right colour temperature is not sufficient to achieve good rendering, you also need high CRI.

  7. #7
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    I second Portra 160 for a neutral palette.
    Provia 100F can have a slight bluish/cold cast in broad daylight. It is often used with a Skylight 1B (light pink) filter in such conditions, but for your use, no filtration at all. Your choices are indeed limited and the best option is to experiment and find out for yourself.
    .::Gary Rowan Higgins

    A comfort zone is a wonderful place. But nothing ever grows there.
    —Anon.






  8. #8

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    This could be a frustrating endeavor. Even if you always use the same film and filtration the color balance depends on the condition of the processing solutions. I would suggest a lab which maintains very close quality control. You may have to shop around a bit.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery



 

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