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Colour temperature adjustment query.

Discussion in 'Help Team' started by Footloose, Feb 18, 2017.

  1. Footloose

    Footloose Well-Known Member

    I'm going to be given some images taken on a Phase One P20 digital back, taken indoors where the colour temp on the P20, was left set on 'Daylight'. I will also be getting the colour temperature data from a Raw image (E-M1 camera) taken at the same time, under the same lighting conditions.

    It's at this point, that my brain has become 'frazzled' because I'm not too sure what the best way of converting the P20 files so they have the same colour temp as those from the E-M1 ... Do I just input (using PSP x10) the setting from the E-M1 image, into the 'box' showing the P20's colour temp, or the 'difference' between the two readings, or do something else? It's just that I'm seriously doubting my limited knowledge of this procedure!
  2. PeteRob

    PeteRob Well-Known Member

    This is a jpeg file that you are processing in Paint Shop Pro? If there is a neutral tone then you can use that to set the colour balance (I assume PSP can do that) else indeed move the colour temperature until it looks right. I'd adjust on the basis of what it looks like rather than matching the colour temperatures but the temperatures should end up having similar values if the two images look the same. If the shots are just "indoors" as opposed to "indoors with artificial light" then daylight might be OK. If the lighting is artificial but not tungsten then you may find a colour cast and have to adjust for tint too. Wait and see what you have before worrying too much.
  3. peterba

    peterba Well-Known Member

    If you have access to Photoshop, then you could try the "Match color" function. It's far from perfect:rolleyes:, but it can be tweaked with sliders to get closer to the image that you wish to match.

    There's also a free-ware thing called the "Metrix plug-in" (Google it) which claims to work with many editing programs, including PS and Paint Shop Pro, and also claims to be more accurate than PS's "Match color" function. NOTE: I have not tried it, so all the usual caveats apply!
  4. Footloose

    Footloose Well-Known Member

    The images are 48-bit (!) Tiff files that automatically open up as RAW files in PSP x9. The owner of these images is also going to be visiting me later today and bringing along the camera and back, so I'm going to have a look at what settings the P20 offers and also taking some test shots with it. I'm rather intrigued by what this back is capable of since the P20 was first sold in 2004!
  5. PeteRob

    PeteRob Well-Known Member

    Pretty big file then. The Phase One backs have come a long way since 2004. I'm on their mailing list having once bought a copy of the "lite" version of Capture One when it existed so I get regular email updates for their hardware and software and invitations to buy new or refurbished kit.
  6. GlennH

    GlennH Well-Known Member

    A 48-bit file is a 16-bit per channel RGB file, FWIW.
  7. Footloose

    Footloose Well-Known Member

    Thanks for that Glenn.
    As an update on what I'm doing, we've encountered a problem ... My friend turned up and he decided that using the 80mm instead of the 40mm would make using the camera a lot less unwieldy; Took this off, but looks like the coupling pin on the 80mm isn't aligning properly with the body, so can't attach it! He decided not to try putting the 40mm back on, in case we make things even worse - 40mm lens and body jammed together! - so it's off to a repairer to sort things out.

    We've obviously looked up this issue on youtube and although it looks like it's 'possible' to sort things out ourselves if this didn't work, our 'messing around' might lead to a much more complex and expensive repair job ... It's just not worth running that risk!

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