3 Replies Latest reply on Aug 17, 2015 9:18 PM by Gaurki

    Remove gradient banding

    StephenMcGowan

      Hi

       

      I'm using Photoshop CC and I am currently trying to remove some background gradient banding seen in some corporate style photographs I've taken recently. I've basically added a gradient circle of light to the black background.

      When viewed on computer the gradient works perfectly - but, when viewed on a mobile phone (which these would most likely be viewed on - on apps such as linkedin etc), the banding seems to be very apparent.

      I've tried various techniques such as creating a dithering layer while working in 16bit: following this guide (Photoshop Actions to fix the banding of Photoshop's gradients.):

       

      • Create a new layer (should be topmost).
      • Fill it with solid 50% gray.
      • Make some noise: Filter > Noise > Add Noise. The settings are Amount = 25%; Distribution = Uniform; Monochromatic = checked.
      • Now hit Command+F (Ctrl+F on Windows) to repeat the noise filter on the same layer (if you're curious why, watch the layer's histogram as you perform the noise filter the first and second time).
      • Set the layer to Linear Light. A great blending mode for this purpose. The darker half of the shades is implemented as inversed linear subtraction (like Linear Burn), and the lighter half as linear addition (like Linear Dodge).
      • In the Layers palette, set the magic values for the layer Opacity to 1% and the Fill opacity to 19%. You could (but don't, really) read the small note below about all the gory details*.
      • We're done. Now lock the layer (the padlock icon in the Layers palette) so it won't react to mouse input. You can forget it exists.

       

      I've also added noise to the gradient layer to see if that seems to help - but it doesn't really.

       

      I'd then merge all working layers together, resize to 960 x 640, convert to 8bit and save.

       

       

      Any advice would be greatly appreciated.

       

      Pictures below:

       

      Computer Image:

      mike1blue960.jpg

       

      banding1.jpg

       

      Thanks,

       

      Stephen.

        • 1. Re: Remove gradient banding
          ssprengel Adobe Community Professional & MVP

          What happens if you do the banding reduction process after resizing to 960x640 but before converting to 8-bits?  And if you're not, already, put the banding-reduction-noise layer below the photo but above the gradient.

          • 2. Re: Remove gradient banding
            norman.sanders Adobe Community Professional & MVP

            Without being able to test various approaches to solving the problem before posting one here, all that is available is to work with images you posted.  In both the original and in the second image (which has increased contrast that makes the banding more apparent), making a loose lasso selection of the offending area and applying a Gaussian blur eliminated the banding. Not fancy, but it worked as a final step. Perhaps it is worth a try.

            • 3. Re: Remove gradient banding
              Gaurki Level 1

              I think when you downsample to the small size Photoshop is automatically sharpening the image. It's great to help little details show up at tiny sizes but can increase banding. Maybe try resizing with "Bicubic" instead of "Automatic" in cases where gradients are messing up (and you don't have time to select and blur away the sharpened edges on small image).