Latest Vuescan and color neg problems

Discussion in 'Digital Darkroom' started by ron_hacker, May 14, 2021.

  1. Interesting video on histograms. I learned a lot. Thanks. Now trying to apply it to scanning, I still have questions.

    I adjust the levels sliders on Epsonscan to expand the range of the prescan. (I scan at 16 bits grayscale for BW film and 48-bit color for chromes). So if let's say the image runs from 20-210 on the Epsonscan pre-scan, I set black and white levels arrows to 15 and 215. What should I do with the Output settings if 0-255 is counterproductive? Set them to the same that I set the input: 15 and 215 in this case so they match? Something else?

    As a separate procedure, does it make sense to just scan "flat" and do all the level adjustments in Lightroom? I've tried it this way and haven't noticed the difference. But someone said I lose data this way. Is that true?
     
  2. digitaldog

    digitaldog Andrew Rodney

    Nothing. Or you use one and not the other depending on what the prescan needs to fit your desires. I explained it's a yin/yang (or teeter-totter if you must). You absolutely do not need to adjust one or the other but maybe you do to make the image appear better; but both makes no sense. You're making a set of dark grays black, then making a set of those dark grays lighter gray; pointless. It is like clipping to black (using other tools), then making them less than black. Why?

    Open some images in Photoshop and play with the Levels command. Try on a black to white gradient or similar and you can see what Input and Output do to the image. Should be no different in the scanning software.

    It makes no sense to make a scan 'flat' unless you have really poor scanning tools and you wish to then adjust in Photoshop in high bit with its better toolset. Even if there's no data loss, if the toolset is more or less equal, why do this later when the scanning software can give you what you wish at the scan stage? If you can't adjust in high bit after the scan, then you want to do this at the scan stage (or find better scanning tools to do so). It doesn't take the scanner any longer to scan a color or tone appearance you wish before it even creates and saves the pixels. After the fact, not so much. But again, if the scanning tools are subpar and you can get high bit data out to adjust afterwards in better software, that's what you should do.
     
  3. Thanks for the suggestions. I'll work on some scanning to see how input and output settings work against each other.

    Regarding scanning flat, it's quicker way to scan since you don't have to adjust each photo before the scan. Of you're going to do some editing in LR anyway, you might as well do the leveling there. Also, like raw vs jpeg, scanning flat leaves you more options in the future especially as software is improved. Also once you make settings before the scan, you're locked in to those afterwards like a jpeg.
     
  4. digitaldog

    digitaldog Andrew Rodney

    Tutorial 3 - Page 1
    If we begin by considering the "Input" slider bar we find three triangles, black, grey and white. These triangles represent the "shadow", "midtone" (brightness/contrast or gamma) and "highlight" adjustments. Moving the "shadow" and "highlight" slider towards the centre will increase image contrast. Moving the "midtone" slider to the left brightens the image, whilst moving it to the right darkens the image.

    The levels "Output" slider bar allows us to reduce image contrast by compressing the data and making a dark pixel less dark or bright pixel less bright. The "Output" control can be used for targeting an image for particular print characteristics, e.g. setting the maximum black at level 5 and minimum highlight at level 250. This feature can be quite helpful when the user finds that their particular printer model tends to "block" what should be perfectly printable "shadows" or "blows" well detailed "highlights" out to white .

    You know the old saying? "You can pay me now, or you can pay me later". I told you when scanning flat and fixing later is a bad idea and when it is a good idea.
    I'm not alone:
    Out of Gamut: The Skinny on Scanner Color | CreativePro Network

    It isn't anything like raw vs. JPEG. You're locked in with JPEG, or not locked in with raw, either way with a JPEG sir; it doesn't support high bit!
    You can edit a high bit TIFF after the scan without any issue.
    You can allow the scanner to produce a more ideal high bit TIFF at the scan stage and edit after the fact as well.

    Once again:
    Out of Gamut: The Skinny on Scanner Color | CreativePro Network
     
    Last edited: May 21, 2021

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