Light and dark fringing that doesn't look like chromatic aberration

Discussion in 'Digital Darkroom' started by russellcbanks, Jun 17, 2021.

  1. These are details of a raw image (with no camera raw tone adjustments) made with a Canon 6D Mark II and Canon 24-105 L series lens. One has no sharpening and the other has Amount: 40, Radius: 1, Detail 25, Masking 10. (Lightroom defaults, I think)

    Can anyone advise me on why I got the white line on the left side of the purple shape, and the dark line on the right side? As you can see, they're visible in the unsharpened file, and get worse with the sharpening.

    Chromatic aberration removal was checked, but the amount was zero, and there's no hint of the purple/green fringing I usually see with chromatic aberration. When I tried increasing the amount, a dark gray fringe quickly appeared.

    With tone adjustments and subsequent work in Photoshop, they become even more apparent, especially on a 20x24 print.

    Also, any ideas on the most efficient way to get rid of the lines in Photoshop? I was under deadline and resorted to manually painting them out with the clone stamp tool. Uggh. I know there must be a better way!




    Russell-C-Banks-01-Yellow Slide, 2019.jpg
    Full image

  2. digitaldog

    digitaldog Andrew Rodney

    Without the raw, it isn't possible to state if this is part of the raw processing or not. And there are all kinds of settings, sharpening and otherwise affecting the raw in this converter. There is no true 'off' sharpening for one. Even if you turn 'off' or set all sharpening to zero. So it would be useful to see the raw data itself in say RawDigger to know what is really going on here.
  3. Thanks, Andrew. I've download a RawDigger trial. Should I have it create some kind of report for you to see? Or would you like me to upload the DNG file somewhere?
  4. digitaldog

    digitaldog Andrew Rodney

    RawDigger should allow you to view the raw data without processing (within limitation); do you see the white line?
  5. The white line appears to be light reflection off a ripple in the canvas material. There's a few more white lines just like it in the blue as well as the purple. They're nothing to worry about. You could perhaps paint along them with the paint brush set on a low opacity until the stark whiteness of the lines disappears. Eye-drop the color next to each line first.
    Last edited: Jun 18, 2021
  6. How about reducing the LR clarity around those boundaries? I suspect it may be artifact of sharpening or of excessive contrast when applied overall. My general reaction however, is like kmac's: nothing to see here. I doubt any normal (non-pixel peeper) will notice anything amiss, and in the context of the image as whole pretty insignificant. One complication is that the lens is not focused (and rightly so) on the bottom of the pool, so you are seeing out-of-focus effects added to the mix.
  7. I do see a small amount of what looks like edge fringing on the edge of the shape. It looks a bit like haloing from sharpening except it seems present before sharpening. But in the full image, it doesn't seem a problem. Sometimes looking at an image at high magnification will reveal problems that the eye doesn't see at normal viewing distance.
  8. OK, it's been said above but I will amplify. I see radial waves spreading out from the child, like a rock into water. The peaks of the waves cause variations in color, all natural and part of the image. It looks good to me as is.
  9. Here's a screenshot of it opened in RawDigger. No black line, but the white one is clearly there.

    Probably just an instance of physics and digital imaging, and there's nothing to do but fix it in Photoshop. I'll look for a way to remove it without literally painting within the line. I saw a reference to adding an empty layer above the image, set to color blending mode... There appears to be several ways to approach this...

    digitaldog likes this.
  10. How does this look ? Two minutes to clone the line out in PS

    White line cloned out.png
  11. digitaldog

    digitaldog Andrew Rodney

    I think you worked on the 'wrong' white line.....
  12. Not sure how this improves the picture overall, and I didn't think you were worrying about the perfectly normal ripples.
  13. Oh ok, my mistake, but the white fringe line on the edge is so negligible in the full image, It's perplexing why you're concerned about it, it really can't be seen to the naked eye. Even expanded to fit a 20x24 print size, it's only vaguely noticeable in a few spots.

    The black fringe line is more noticeable and my attempt at cloning failed because the clone tool itself left a black fringe line. I'm demonstrating it by cloning right into both the blue and the purple with two clone circles so you can see what they did, in PS. Cloning other images I have didn't produce the black fringe so IMO the processing of your image was done with poor quality software, either in the camera, externally, or both. Or perhaps the resolution of the shot was far too low to start with. The "black" line is not really black, but dark purple and dark blue, the software, whatever it was, somehow made the pixels dark where the two colors join.

    Your image is also very vulnerable to different software programs. If you look closely again at the image below, you'll now see a "black" fringe where your white fringe is, or was.

    Black fringe line .jpg

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