No announcement yet.

LightEQ interesting observation

  • Filter
  • Time
  • Show
Clear All
new posts

  • LightEQ interesting observation

    I thought this was interesting. Look at the patterns I get on homogenous grey boxes when applying LightEQ ! Ultimate 2022... weird!

  • #2

    Yes, Interesting.
    It can also be produced in Ultimate 2021 too.
    Also interesting is that it isn't just a display effect. If you export the image the export has the effect baked in.

    If you turn on the Exposure warning and adjust the curves to right on the edge of clipping, it's also interesting to see how the warning is not uniform over a standard black filled background
    The green warning of course is only a visual effect and not passed on when you exit LightEQ..

    Click image for larger version

Name:	LightEQ.jpg
Views:	98
Size:	114.1 KB
ID:	57601
    Using a 16 bit image doesn't overcome it nor does using different color profiles


    • #3
      This is really quite an interesting "feature" of the Light-EQ tool, which I also sort of noticed slightly occuring sometime ago while editing

      I started a question on the DPReview science and technolgy forum with the hope of diggging deeper into it.
      link--> How an image editing software works?: Photographic Science and Technology Forum: Digital Photography Review (
      Quite a long and a partially geeky technical discussion followed.

      After the general discussion I summarized what was considered to be a possible explanation here
      link--> Possible explanation for the ACDSee Light-EQ effect: Photographic Science and Technology Forum: Digital Photography Review (

      It would be interesting to here if ACDSee have any inputs to that ?

      In normal use of the Light-EQ tool it would be definitely be prudent to avoid any such very sharp transitions of the sliders to avoid this. I use Light-EQ a lot and think it works well. I always try to keep the adjustments of these the 9 tone band slider quite “smooth”; meaning not too much difference between any two adjacent sliders.
      Last edited by Trevor; 10-13-2021, 05:38 AM.


      • #4
        I also noticed something else a bit strange but quite related about the Light-EQ tool that you can see when looking at the histograms

        If I create a new (.tiff) image with a white background and a grey box
        then the histogram of that image viewed in Edit mode is like this (photo 1)
        -- you can see as expected, the single clean white spike at the right for the background and a single spike in the middle for the grey box

        If in edit mode I now select the Light-EQ mode but make no changes with the sliders whatsoever, the histogram immediately changes to this (photo 2)
        -- notice how we now have a set of extra tiny little spikes added.
        I'm assuming these little spikes are caused by that extra sharpening (local contrast enhancement) that is possibly applied automatically by Light-EQ in addition to any tone curve changes you make.

        Also, on the the histogram type of display shown in the Light-EQ tool itself, that single spike is shown, not as a spike but, as a very wide box (photo 3)

        Interestingly when the image is opened in Develop mode, the histogram shows up immediately like in photo 2, already with those extra little spikes, seemingly because Light-EQ is always applied in develop mode (with zero slider adjustement at first, but already always with the local contrast enhancement)

        I think this supports the conclusions made over in DP Review about the Light-EQ tool adjusting the tone curve and in addition applying a "local contrast enhancement"

        Good or bad?, I have no idea?

        Attached Files