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Participant
January 4, 2020
Answered

Why my gaussian blur is like that?

  • January 4, 2020
  • 2 replies
  • 2569 views

Hey guys, I've been using my PS lately, but I noticed that my Gaussian Blur isn't normal.

It looks like a bug or something related.

Can someone tell me what to do?

https://prnt.sc/qj46if

This topic has been closed for replies.
Correct answer D Fosse

This is standard 8-bit banding. If this is a 16-bit file, it's in your display system.

 

The display path, from video card to the screen itself, works in 8 bit color depth. That means you only have 256 discrete steps per channel. This is a narrow gradient, so you may have only, say, 15 steps from the darkest to the lightest. That's what you're seeing.

 

The only way to avoid this is to get a 10-bit capable monitor and a 10-bit capable video card. Both are somewhat more expensive than your standard off-the-shelf consumer product lines.

2 replies

D Fosse
Community Expert
D FosseCommunity ExpertCorrect answer
Community Expert
January 4, 2020

This is standard 8-bit banding. If this is a 16-bit file, it's in your display system.

 

The display path, from video card to the screen itself, works in 8 bit color depth. That means you only have 256 discrete steps per channel. This is a narrow gradient, so you may have only, say, 15 steps from the darkest to the lightest. That's what you're seeing.

 

The only way to avoid this is to get a 10-bit capable monitor and a 10-bit capable video card. Both are somewhat more expensive than your standard off-the-shelf consumer product lines.

Participant
January 4, 2020

Oh, but I used to do some smooth Gaussian Blur effects on brushes. But when  i switched my computer this problem appeared.

D Fosse
Community Expert
Community Expert
January 4, 2020

Unless you have a 10 bit monitor and a 10 bit video card (both expensive) I can guarantee you that you had this before, you just didn't notice it. With a standard GPU and a standard display, there are only 256 discrete steps to display in total. There is nothing, no data, between those steps.

 

Perhaps you see banding that I don't see in these screenshots. Perhaps you have a display with inherent banding, or banding introduced by calibration adjustments in your video card. I won't see that here. I only see the normal and expected 8-bit banding in your screenshot.

SCP173
Participant
January 4, 2020

Hey,

I'm trying to take a look at the screenshot, but all I see is black. Is there any way you can take a screenshot again, possibly with your native computer settings? 

Participant
January 4, 2020

I'm sorry, I'm gonna to upload another screenshot
https://prnt.sc/qj5n8l

As you can see, the Gaussian Blur effect is not doing a smooth blur, the layer is doing a kind of lines.

I want to do a smooth gradient using the Brush and the Gaussian Blur 

SCP173
Participant
January 4, 2020

First, I would take a look to see if your computer screen is condensing the blur and creating the lines. I'd zoom in a lot and see if the lines get bigger, or disappear. If they disppaear, when you export the file to a PNG, there should not be any lines. 

 

If that doesn't work, it might also be because the brush size you are using is really large. Just to clarify though, you are using a soft brush and then applying a Gaussian Blur filter on it?