Blur brush foxes me.

[Patrick Bell]

I have loaded a photo, duplicated the layer, selected the blur brush and started painting but it seems to do nothing. The inpainting brush fwiw leaves a red trail and does work. Opacity, flow and hardness are all 100%.

So after some searching I tried a live filter with gaussian blur. Nothing happens when I brush over this except that when the mouse button is not pressed I can see the un-blurred image through the brush.

Clearly I am doing something wrong. I have attached a screenshot and the image up to now.

 

kookaburrah.afphoto

[iconoclast]

Hi Patrick!

You don't need the Live Filter for the Blur Brush. The filter is for global bluring. The strength of the Blur Brush can be adjusted in the context bar. You find it under the menu bar if the Blur Brush is selected.

Take care that you are on the right layer and that it is a Pixel Layer.

[GarryP]

This seems to be two different issues.

In addition to the advice above...

For the first issue, try selecting a different brush.
Some brushes – those with some transparency, for example – are not great for this sort of thing in all cases.

For the second issue, in the screenshot you seem to be painting with white onto a mask – the Live Gaussian Blur Filter Layer itself has its own mask – and that will cause no effect to the blur.
Painting with white onto a mask says “let the background ‘through’ the mask”, and painting white onto a Live Filter Layer says “let the filter do its job here”.
Try painting with black/grey and maybe choosing a different brush, as above.

If none of that helps then it might be best to stick to one issue at a time and get advice for that before asking about the other, otherwise it could get very confusing.

[Patrick Bell]

OK lets simplify it. I have loaded the image, clicked the blur brush and it has no effect. The inpainting brush works but that isn't what I want to do here.

I have attached a screen shot of my settings. and the aphoto file. I tried black or white and the checkered circle is my brush when not holding the mouse button

 

[Patrick Bell]

Kookuburrah.afphoto

[PaulEC]

46 minutes ago, iconoclast said:

The strength of the Blur Brush can be adjusted in the context bar.

It's worth noting that the opacity setting does nothing (the effect is the same at 0% as at 100%). The strength of the effect can only be changed using the flow setting.

 

[GarryP]

That checkered circle should not be shown when using the Blur Brush.
The checkerboard is where the image has been (or will be) given transparency, which shouldn’t happen with the Blur Brush.
That’s very strange; maybe I’m missing something which should be obvious.

[PaulEC]

The Blur Brush and the Inpainting Brush do two completely different things, so there is no point in comparing what they do or how they work!

I assume you want to blur the background and keep the bird sharp. If so, the way to go is to use a Gaussian Blur filter to blur the whole image, then paint on the blur layers mask, using a brush from the "Basic" set of brushes, using black to "paint" back in the area that you want to be sharp. (Hint: In the Gaussian Blur filter dialogue, enable "Preserve Alpha" so that the blur goes up to the edge of the image.) Of course, you could do it the other way, fill the whole mask with black, then paint with white on the area you want blurred.

[iconoclast]

It's a very subtle effect. I know that even from other programs like GIMP, in which Forum there also have been discussions about it. So it is possibly meant to be this way. I don't use this brush very often.

The main influence seems to have the "Length" setting, as far as I can see. That makes sense in the meaning of Blur Radius, I think. (Edit: This was bullshit, because the "Length" only influences the Stabilsator)  . But as I said, the effect is subtle. You will not get a totally blurred image by using this brush.

What you can do to get a stronger blur is to use the "Gaußian Blur" Live Filter, adjust the blur factor you want and use a normal brush with the Foreground Colour Black. to resharpen the areas you don't want to have blurred. Unfortunately it doesn't seem to work vice versa, by filling the Gaußian Blur Live Filter with white and then blur it with a brush.

At least this is how that brush behaves in my case. I see this checkerboard too (if the background is set to Transparency - otherwise I see a white point). Don't really know why. Can't exclude that it is a bug.

[PaulEC]

11 minutes ago, iconoclast said:

I see this checkerboard too (if the background is set to Transparency - otherwise I see a white point). Don't really know why. Can't exclude that it is a bug.

If this happens when using the Blur Brush then something is definitely wrong somewhere! (Unless you are using some really weird settings, only the Erase brush should show transparency.)

11 minutes ago, iconoclast said:

The main influence seems to have the "Length" setting

The length setting only works when using the Stabiliser, it controls the distance between the brush itself and the point you are dragging. (Sorry, I'm not sure what the correct name is for that!)

[iconoclast]

6 minutes ago, PaulEC said:

If this happens when using the Blur Brush then something is definitely wrong somewhere!

You're possibly right. I don't know why a Blur Brush should show up like an Eraser. I'm on Windows 10 with AfPhoto version 1.10.5.1342. But anyway, the Brush creates a very subtle blur effect. I doesn't erase.

[PaulEC]

I'm also on Windows 10 and the Blur Brush looks like a blur. As you say the effect is quite subtle! I usually find it's easier, and more effective, to use a blur filter with a mask, as mentioned above.

EDIT: Just a thought, but I wonder if it has anything to do with the Open CL setting in Preferences, (mine is off.)

[Patrick Bell]

well, 100% or 0% flow makes no difference either. PLus "That checkered circle should not be shown when using the Blur Brush."

Not filling me with confidence in the blur brush. This is a mature program now and yet it doesn't fill me with confidence - I am often foxed when tools just don't work as I'd expect them to.

 

 

[iconoclast]

26 minutes ago, PaulEC said:

I'm also on Windows 10 and the Blur Brush looks like a blur. As you say the effect is quite subtle! I usually find it's easier, and more effective, to use a blur filter with a mask, as mentioned above.

EDIT: Just a thought, but I wonder if it has anything to do with the Open CL setting in Preferences, (mine is off.)

Checked it: Yes, you are right, with OpenCL deactivated it doesn't show this annoying Eraser-like point. There is already a thread about this problem.

[iconoclast]

14 minutes ago, Patrick Bell said:

well, 100% or 0% flow makes no difference either. PLus "That checkered circle should not be shown when using the Blur Brush."

Not filling me with confidence in the blur brush. This is a mature program now and yet it doesn't fill me with confidence - I am often foxed when tools just don't work as I'd expect them to.

 

 

In fact I can't see any way to influence the behaviour of the Blur Brush too - except the brush size and possibly the Hardness (but I'm not sure about the last point). In fact a small brush seems to create a stronger blur effect than a big one. But that might be an optical illusion. The annoying checkerboard/white point can be deactivated by deactivating OpenCL in the Preferences. But I suppose there is a bug in this tool anyway.

EDit: But the effect gets stronger if you paint repeatedly. So it is not completely useless, I think. It is more for fine and subtle retouching. I think we should try to get a statement of a developer about it.

[PaulEC]

29 minutes ago, Patrick Bell said:

well, 100% or 0% flow makes no difference either.

It does, but the change is very subtle. The Blur Brush is not really intended to be used on large areas, more to touch up small items. It really does need to be rethought and improved! (As does the Sharpening Brush.)

[iconoclast]

9 minutes ago, PaulEC said:

It does, but the change is very subtle. The Blur Brush is not really intended to be used on large areas, more to touch up small items. It really does need to be rethought and improved! (As does the Sharpening Brush.)

I compared it with the same tool in GIMP some minutes ago, and the effect in GIMP in fact is even more subtle. And I can't find any ways to get a stronger effect with it there too. Generally, I think, that this tool is really not made for bigger operations. For things like that it wouldn't really make sense. It's for subtle, well targeted retouching. But of course it confuses if you don't see any effect when you first try it.

[h_d]

The blur brush is very very subtle and quite slow. If you want to paint an immediate, strong blur effect onto your image, start off with a Gaussian Blur filter layer masked to the image (as you did to start with), then set an overall blur:

 

In the video above, I invert the blur layer to black, then paint on the blur layer with an ordinary paint brush (not the blur brush) set to white with fairly soft edges. You can make the effect more subtle by reducing the opacity of the brush (Add:  or indeed by adjusting the parameters in the Gaussian Blur layer).

 (I think the bug with the Blur Brush preview has been reported before...)

 

 

 

[iconoclast]

11 minutes ago, h_d said:

The blur brush is very very subtle and quite slow. If you want to paint an immediate, strong blur effect onto your image, start off with a Gaussian Blur filter layer masked to the image (as you did to start with), then set an overall blur:

 

 

In the video above, I invert the blur layer to black, then paint on the blur layer with an ordinary paint brush (not the blur brush) set to white with fairly soft edges. You can make the effect more subtle by reducing the opacity of the brush (Add:  or indeed by adjusting the parameters in the Gaussian Blur layer).

 (I think the bug with the Blur Brush preview has been reported before...)

 

 

 

That's what I was looking for some time ago. But one thing is not clear to me: How did you invert the Gaußian Blur filter to black? Can't find a way to do it.

[PaulEC]

48 minutes ago, iconoclast said:

There is already a thread about this problem.

It has been mentioned a few times (over the years!) - no improvement yet!

[PaulEC]

4 minutes ago, iconoclast said:

That's what I was looking for some time ago. But one thing is not clear to me: How did you invert the Gaußian Blur filter to black? Can't find a way to do it.

It's shown in the video: Select the mask then,  "Layer - Invert" (or Ctrl/Command + I)

[iconoclast]

@ h_d

OK, thanks, I got it. Really cool. I think that's the solution.

[R C-R]

6 hours ago, PaulEC said:

If this happens when using the Blur Brush then something is definitely wrong somewhere!

FWIW, I see the transparency 'preview' when using the Blur Brush too, & I am using a Mac running Catalina, not windows. What is weird about it is if I do not move the brush then after a second or so it reverts to showing a blur preview but as soon as I move it even slightly it goes back to the transparency checkerboard. The Sharpen Brush Tool works normally.

Similar to (I think) the Windows behavior, if I disable Metal Compute Acceleration, the Blur Tool works normally so this seems to be related to hardware acceleration somehow.

[iconoclast]

22 minutes ago, R C-R said:

...What is weird about it is if I do not move the brush then after a second or so it reverts to showing a blur preview but as soon as I move it even slightly it goes back to the transparency checkerboard...

Yes, the same to me on Windows. But it seems to be even weirder (if this comparative exists in english): as I went back some steps in the History and moved the mouse, it first only showed the blur preview - as it should, I think. Not before I pressed the left mouse button/the related button of the stylus, the background shine-through reappeared. I think that this is definitely a bug, because it doesn't make any sense and is very annoying.

[R C-R]

2 minutes ago, iconoclast said:

I think that this is definitely a bug, because it doesn't make any sense and is very annoying.

I think it is a bug too, one related to hardware acceleration ... at least assuming that for you on Windows like for me on my Mac that disabling it makes the brush preview behave as expected.