What’s a raw.tiff?

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    Topic: What’s a raw.tiff? Read 135 Times
  • Hugh Sakols
    Hugh Sakols
    Silver Member
    Posts: 73
    Film and Photo Digitizing
    on: May 19, 2022 at 12:59 pm

    I’m scanning some historic photos for a museum using an Epson V750 pro and Vuescan.  I’m outputting to tiff files, but I’m also getting raw.tiff as well.  What is a raw.tiff file?  How is it possible to have raw and tiff in the same file?   If you ever come through Yosemite, make sure to check out the Yosemite Climbing Museum.  The historic photos are amazing.

     

    Mark D Segal
    Mark D Segal
    Silver Member
    Posts: 671
    Re: What’s a raw.tiff?
    Reply #1 on: May 19, 2022 at 1:47 pm

    If you can make head or tails of this you will understand it; I don’t by the way:

    https://www.hamrick.com/vuescan/html/vuesc24.htm

    My guess is that this is the image produced from raw scanner data [being the three primaries (RGB) + IR per pixel], embedded in a TIFF file format, preserving linear gamma and without any built-in editing to enhance colour or contrast. But I may be wrong. If someone has a more accurate explanation, please write – would be good for Vuescan users to know.

    Mark D Segal Author: "Scanning Workflows with SilverFast 8, SilverFast HDR, Adobe Photoshop Lightroom and Adobe Photoshop". Please check the PhotoPXL Store for availability.

    Andrew Rodney
    Andrew Rodney
    Participant
    Posts: 294
    Re: What’s a raw.tiff?
    Reply #2 on: May 19, 2022 at 2:34 pm

    Most raws are based on TIFF. But the data from a true raw and a rendered TIFF (from trilinear scanning) is very different.

    Scanners do not create raw data. It seems the new ‘rage’ to suggest they do. They can produce a TIFF that’s minimally processed, is that what you really want? Yes if the scanning software kind of sucks and can’t produce, globally, the color rendering you desire. You hand this off to Photoshop or similar and use the tools there. But this isn’t raw rendering.

    This is really what raw data from a camera sensor (which massively differs from a scanner) looks like (attachment 1):

    The gamma encoding from a scanner is moot. Some say linear images appear dark; they only do when the linear profile that defines them isn’t used. Which no one should ever do. A linear scan or capture, with the linear profile, doesn’t appear dark or ugly unless it was scanned too dark.

    Here is a linear capture of a Macbeth. The dark image appears that way because it isn’t using the correct linear profile to define the data. The other does, and looks fine (attachment 2)

    Author “Color Management for Photographers" & "Photoshop CC Color Management" (pluralsight.com)

    Andrew Rodney
    Andrew Rodney
    Participant
    Posts: 294
    Re: What’s a raw.tiff?
    Reply #3 on: May 19, 2022 at 2:58 pm

    “VueScan internally keeps all samples in 16-bit linear format, even when a scanner only supports 10-bit samples, ….

    It is like saying, “I can pour a cup of water into my pint container”.

    Author “Color Management for Photographers" & "Photoshop CC Color Management" (pluralsight.com)

    Mark D Segal
    Mark D Segal
    Silver Member
    Posts: 671
    Re: What’s a raw.tiff?
    Reply #4 on: May 19, 2022 at 3:05 pm

    But you still only have a cup! 🙂

    Mark D Segal Author: "Scanning Workflows with SilverFast 8, SilverFast HDR, Adobe Photoshop Lightroom and Adobe Photoshop". Please check the PhotoPXL Store for availability.

    Hugh Sakols
    Hugh Sakols
    Silver Member
    Posts: 73
    Re: What’s a raw.tiff?
    Reply #5 on: May 21, 2022 at 10:06 am

    Mark, Andrew:

    Thanks for taking the time to answer my questions.  Yes, I always take my scanned tiffs to Photoshop for adjustments.  The tiffs I got look quite good.

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