Adding noise to layer masks

[Alexandru Cojocaru]

Hi, is it possible to add noise (destructively or non-destructively) to a layer mask? (this can be helpful to reduce banding when using smooth gradients inside a layer mask, in an 8 bit document). I did try it by selecting the mask and adding a Noise Live Filter Layer (and also adding Filters-Noise-Add Noise) but it didn't seem to work. Thanks!

[lepr]

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[DWright]

You can also place a live add noise filter layer above the mask in a group as shown in the screen shot below

[Alexandru Cojocaru]

1 hour ago, owenr said:

A tedious workaround: 

 

Layers panel: select the mask.

Channels panel: right click on "Mask Alpha" and pick "Create greyscale layer".

Add noise to the greyscale layer.

Layers menu: "Rasterize To Mask" while noisy grey layer is selected.

 

You will have a new noisy mask which can be used instead of the old mask.

 

 

Thanks for your reply @owenr, this seems to be the only way to do it.
It's a shame that you can't apply any filters directly to a mask (like you can in Photoshop). 

[R C-R]

4 minutes ago, Alexandru Cojocaru said:

Thanks for your reply owenr, this seems to be the only way to do it.

??? Is there some reason the non-destructive method @DWright just mentioned will not work for you?

[Alexandru Cojocaru]

1 minute ago, R C-R said:

??? Is there some reason the method @DWright just mentioned will not work for you?

I did try it and it dosen't work. The Mask Layer get's applied to the noise, instead of the other way. I want the noise to be applied on the mask.

In the method shown by @DWright the noise affects the layer underneath (and it get restricted by the mask).

[lepr]

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[lepr]

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[R C-R]

1 hour ago, owenr said:

As presented, it creates a masked noise adjustment layer on top of the image underneath the group, and that noise will be affecting colour in pixels instead of opacity .

OK, I see that is different from what is desired, which is opacity applied to the noise filter layer, right?

 

If so, have you considered going about this the other way around, so to speak? By that, I mean creating the noise filter layer first (which already has a built-in mask). Next, make a selection using the usual selection tools (with or without the noise filter layer visible, whatever works best for you) on the Background layer. Then, select the noise filter layer & use the Paint Brush or Flood Fill tool to change its opacity. Or skip making the selection & just use the Paint Brush directly on the noise filter layer. Either way, by changing the opacity of the Paint Brush tool or its grayscale color, or its hardness; or maybe by refining the selection if you use one, you can get a variety of effects besides 'all or nothing' noise opacity.

[lepr]

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[Alexandru Cojocaru]

2 hours ago, owenr said:

 

Yes, I previously suggested in some thread that we should be able to attach all adjustments and filters to a mask as if the mask was a regular greyscale layer.

You can attach Curves and Levels adjustments to masks - set their target channel to Alpha instead of Master.

 

I think I'll post a proper request for the ability to handle masks in every way that we can handle a pixel layer.

  

 

It would be amazing to have that functionality in a future version of Affinity Photo. (Curves and Levels work great this way, we just need the rest of adjustments and filters to work in the same way).
A small note regarding layer masks: would be great, after you Alt+click on the mask to see it, to be able to Alt+click again on it to come out (instead of clicking on another layer or pressing Esc) (I guess I'm just used to the 'Photoshop way' and it's hard to break the habit)

[lepr]

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[R C-R]

4 hours ago, owenr said:

 

No, the desire is to add noise to some existing layer's mask and thus make that layer's opacity be noisy.

But a noise filter layer already has an existing mask. Why do you need yet another layer mask to make anything noisy?

[lepr]

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[R C-R]

40 minutes ago, owenr said:

No extra mask is being added. Some object already has a mask, but the mask contains offensive banded gradients, so noise is being added to that mask to make that object's opacity less banded.

Now I am really confused! As I understood it, in the first post the idea was to make 8 bit gradient banding in a mask less noticeable. But that is color banding, not opacity banding, is it not?

 

Are we still talking about that or something else?

[lepr]

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[R C-R]

14 minutes ago, owenr said:

A mask modulates opacity.

Banding in a mask causes banding in opacity.

Technically, a mask modulates the opacity of whatever it masks. But we can't actually see the opacity of a mask -- it can be represented by a grayscale image but that it is not really what it is. So what we see is banding in the underlying layer(s), which is manifest as color banding of that or those layers.

[lepr]

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[R C-R]

7 hours ago, owenr said:

Now you understand why Alexandru wants to add noise to a banded mask.

I still do not understand why the mask built into the noise filter cannot be used for that.

[anon1]

15 hours ago, Alexandru Cojocaru said:

It would be amazing to have that functionality in a future version of Affinity Photo. (Curves and Levels work great this way, we just need the rest of adjustments and filters to work in the same way).
A small note regarding layer masks: would be great, after you Alt+click on the mask to see it, to be able to Alt+click again on it to come out (instead of clicking on another layer or pressing Esc) (I guess I'm just used to the 'Photoshop way' and it's hard to break the habit)

Very much 

[lepr]

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[R C-R]

31 minutes ago, owenr said:

Don't worry about it. Maybe if you do some experiments with making masks noisy, then it'll all come clear (pun not intended).

If I want to add noise to an image, I am going to use a Live Add Noise filter for that. This allows me to control the opacity, intensity, & blend mode as I see fit, as well as choosing between monochrome & color noise, whichever suits my purpose. It is also non-destructive & updates in real time, so there are no regrets or surprises to worry about.

 

If I need to mask the added noise for some reason, I am going to use the mask already built into the filter for that, using the methods already mentioned. Together with the filter options, this gives me a tremendous amount of fine grained control over both the effects of the filter & where it is applied.

 

What I am not going to do is add a large scale (in opacity range or image area) gradient to a transparency mask that introduces banding to 8 bit images. To me that is just creating a problem that I will have to solve with some awkward workaround. Metaphorically, I regarding it like swatting a fly with a sledgehammer & then having to fix the dent.

 

As always, your mileage may vary.

[lepr]

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