Luminous Landscape Forum
Raw & Post Processing, Printing => Digital Image Processing => Topic started by: wmchauncey on June 16, 2015, 05:05:34 pm
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How do I avoid the banding that occurs when using the gradient tool in PS CC?
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How do I avoid the banding that occurs when using the gradient tool in PS CC?
Perhaps if you gave more info and posted an example .... ?
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I can do that...working in ProPhoto/16-bit...check out the histogram
(http://i329.photobucket.com/albums/l383/chauncey43/banding.jpg) (http://s329.photobucket.com/user/chauncey43/media/banding.jpg.html)
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I can do that...working in ProPhoto/16-bit...check out the histogram
Hi,
The histogram shows a triangular warning symbol you need to click on if you want to see the data from all pixels, instead of one of the cached levels.
The screen print may show the effect of the (large gamut?) display profile and the video card driver, but is the file itself also posterized, e.g. when you look at it in another viewer? Is proofing switched on, and which profile is chosen?
What is the level, or are the levels/histogram, of the original Layer 1 before adjustment? What does the Adjustment Curve look like? Maybe there are just not enough levels for a smooth gradient?
Cheers,
Bart
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I can do that...working in ProPhoto/16-bit...check out the histogram
Does anybody know if the gradient tool works at 15 bits in CC?
One way you can try to tell whether the 15-bit data is posterized or whether it's just your less than 8-bit video path's fault is to apply a large USM to the merged layers (e.g. 500% 10+ px). If the data is posterized this will bring out contour banding. If the data is not posterized you will instead get weird but smooth shapes. You can see a recent example of the effect of this procedure here (http://www.strollswithmydog.com/iq-raising-iso-vs-pushing/) (scroll down to the section 'Taking the Video Path Out of the Equation').
Jack
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Had some time on my hands this morning...created a new image>10x255 inches filled with black>
duplicated image (CNTRLl J) filled with white>applied gradient mask...see notched histogram.
There is definite banding...I can only assume that there is 256 different bands.
Applying 50 pixel Gaussian blur/changing bit depth or color space... has no effect.
To add another monkey wrench...when I watch this video...https://www.youtube.com/watch?v=4yEumr1tg5s I see banding
(http://i329.photobucket.com/albums/l383/chauncey43/histogram.jpg) (http://s329.photobucket.com/user/chauncey43/media/histogram.jpg.html)
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Okay...I think that I found the reason but, I don't know the why...it concerns the Cache Levels within
the Preferences>Performance section. Default is set to 2, I had been using 6 (don't remember why).
Anyway...when you choose anything twixt 2 and 8, you get banding. But, if you set it to 1 and repeat
the whole process...banding is major league reduced.
As a reminder, I opened an image>filled it with 05, 05, 05>duplicated with CTRL J>
filled with 250, 250, 250>applied gradient mask...very minimal banding with Cache Level set to 1.
Now, before you assume that I'm an effing genius...I found this...http://feedback.photoshop.com/photos...assive-banding
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Sorry, bad link, i think.
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The banding is probably a result of the display, display path, not the data. One thing to try is turning OFF GPU in PS, some have reported it causes banding on-screen.
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You mean the Graphics Processor, right?
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You mean the Graphics Processor, right?
Yes, in Preferences>performance.
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Okay...I think that I found the reason but, I don't know the why...it concerns the Cache Levels within
the Preferences>Performance section. Default is set to 2, I had been using 6 (don't remember why).
Anyway...when you choose anything twixt 2 and 8, you get banding. But, if you set it to 1 and repeat
the whole process...banding is major league reduced.
As a reminder, I opened an image>filled it with 05, 05, 05>duplicated with CTRL J>
filled with 250, 250, 250>applied gradient mask...very minimal banding with Cache Level set to 1.
Now, before you assume that I'm an effing genius...I found this...http://feedback.photoshop.com/photos...assive-banding
I am looking forwards to trying tour solution with the reduction of cache. I have had the same issue for years when trying to place a solid gradient in a layer I photoshop. Banding.
The link you listed in this post is dead. Is there another link for that page?
Thanks.