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Can anyone explain to me why, within the gradient adjustment line box, I have a perfectly smooth top-to-bottom, black-to-white gradient, but the actual gradient in my shape object is a frumpy, unsmooth mess with smooshed color blends?

Driving me NUTS@^*$%!!!
 

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thebestcpu

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Hi Agentmuller

Doing an examination of a slowly varying gradient from a highly compressed jpg that is not at 100% viewing is pretty limited for analysis so I suggest posting a PNG snippet that is viewed at 100% (or the whole thing as a PNG hosted and linked if it is too large)

So without the better images, here are my best shots at the issue and they are based on my thoughts that the issue is not in the gradient itself yet rather in your monitor calibration or as an illusion in your eye (don't scoff yet :) )

With my Mac, when I take a screen shot, it uses the actual data from the screen after color management and also includes the ICC profile of the monitor (I have it set to record in PNG). I don't think that is the case for the supplied image (its is sRGB) and I don't know that even if you did a 100% screen shot that I would be able to reproduce any monitor issues on my screen since not all issues arise from problems in the ICC profile.

I am not sure it is a monitor issue at all yet maybe instead an optical illusion. Below are two images of your supplied JPEG blown up to 3200% and high contrast put in just one section area. Note that the banding that is seen is the same outside the gradient adjustment line box as well as inside (other than some JPEG artifacts). The first image is directly from your image with the color and the second is only looking at a luminosity version of the image. The higher level of banding in the color version is also an artifact of JPEG compression so I suspect you won't see that on your monitor either.

There is a third factor which is also an optical illusion that happens at inflection boundaries of gradients where tones can be amplified and the eye will not precieve the right tone (in case you are referring to the bunching at the inflection points in the gradient) named the Cornsweet illusion. The last image is an extreme example of that illusion where the upper and lower tones of the chips in the image on the left are identical. Just covering the middle section between the chips (done on the exact same image on the right) reveals the deception to the eye. If you don't believe this just cover the same area for the image on the left with your finger or a dark piece of paper. The same issue happens to a lesser degree at inflection points on a gradient where sometimes they seem a little extra bright or possibly too dark.

Lastly, you can take the image with a color picker with the info panel and go along the gradient inside and outside the adjustment line and probably prove that there is not difference and the it actually does follow exactly what you created in the gradient.

That's my best guess without a better image.

John Wheeler

Screen Shot 2017-06-06 at 5.57.05 AM.png

Screen Shot 2017-06-06 at 5.55.19 AM.png

Cornsweet-illusion.jpg
 
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