Adjustment Mask Layers

[Davg]

I hope someone can explain something which as a newbie is puzzling to me.

From what I can gather, adjustment layers come with built-in masks and having added an adjustment, one can then begin painting on a mask. But in a couple of tutorials I've looked at they suggest creating an adjustment and then adding a mask to the adjustment. The screenshot shows a Black & White adjustment, which I've painted on without adding a mask and it seems to work as you would expect it to.  So my question is: Why add a mask to an adjustment if the adjustment already has a mask attached to it and is there a difference between the two methods? Or am I misunderstanding something?

I would appreciate any help with this as it's driving me crazy! 

[Old Bruce]

1 hour ago, Davg said:

Why add a mask to an adjustment if the adjustment already has a mask attached to it and is there a difference between the two methods?

The mask you add could be, for instance, a text layer, or a precisely sized rectangle/ellipse. These are things which are impossible to paint/draw.

[Bri-Toon]

Think of a mask as to hide something on your layer. If you were to get a picture of a man walking and another picture of a door, the mask would allow you erase part of the man to make it look like half is in front and the other half is behind walking through. It allows you erase areas of the mask without erasing any actual pixels. Adjustment layers are more for correction.

[Davg]

Thanks for your replies. I can understand what Old Bruce says about a text layer or shape, but I was referring to adjustment layers, and the example I gave was adding a Black & White adjustment layer. If I was to add such an adjustment does it come with a mask already attached or would I need to add a mask?

[Gnobelix]

 

Hello Davg,

in my understanding, the built-in masks only works on this one adjustment level.
A masking layer can affect all levels, or just one level
See also answer from Old Bruce and Bri-Toon.

 

Cheers

[lepr]

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[Davg]

I have just watched this official Affinity Photo-Mask Layers where the annotator says "...I'll just clarify that adjustment and filter layers inherently have there own masks. So there is absolutely no need to add a separate masking layer to them", which is what is what I understood to be the case. But the point I was making was that a couple of tutorials I had looked at suggested adding an adjustment layer and then adding a mask which didn't make sense to me. I now know that I can add an adjustment layer and paint straight on the mask instead of adding a separate mask. Thanks for all your replies.

[Bri-Toon]

Hi Davg, I think I understand where you're confused.

You want to know the reason for adding an additional mask when adjustment layers already have masks built in to them. The best way to answer is that different types of masks have different benefits. If you were to create an adjustment mask on an image and then recolor it, you could use a selection tool to subtract areas you don't want colored. (That only subtracts color.) Whereas, if you use a pixel mask, then using a selection tool to subtract areas will subtract the pixels (everything in the selection). I hope this helps.

[firstdefence]

You can use separate masks for organisational reasons so different masks, mask different areas and you can turn the masks on or off without affecting the other masks, else masking on the actual adjustment or live filter layers would be a job lot affair.