Brush as Eraser (Painting into Alpha)

[whitehead]

Hello - I was quite an enthusiastic supporter of the Affinity Photo Windows beta but the absence of being able to use the brush as an eraser was a bit of a deal breaker for me. I had hopes that by now this might've been implemented, but downloading the current trial seems to indicate not.

 

Painting into the alpha is pretty ubiquitous elsewhere - Clip Studio, Paint Tool Sai and so on include as a standard - but I don't know whether its absence is a 'won't', 'in the pipeline', or a 'can't'. Artrage is probably an example of the latter, I suspect, with a complex brush engine perhaps unable to handle the complexity of alpha removal on a 'live' canvas surface. I haven't used Painter in years and I can't recall if it can or not.

 

I'm probably not alone as a digital artist who partially relies on flipping the current brush into eraser mode as part of their workflow - as lovely as Affinity Photo is, particularly with the inbuilt Daub brushes, without for me it doesn't absolutely offer the alternative to the rest I'm looking for, which is frustrating given the integration with Designer.

 

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[Henry Stahle]

This "erase with any brush" / "paint with aplpha" is easy done in Affinity. First select the eraser tool, next select the paintbrush you use, and off you go! Switch between keyboard E and B to erase or paint. :)

[Julian23]

Sorry, I was also looking for this, since I am really used to this functionality.

 

with (E) - Eraser I can select an eraser and change its size - but I cannot select a Brush style.

 

with (B) - Brush I can select a brush tool and I can paint, but it does not paint into the Alpha channel but simply paints the current color. 

 

So using this technique the above "painting into Alpha" cannot be done. 

 

The only possibility is to NOT use the the eraser and create a masking layer.  With the brush I can paint transparency which way and I can also remove it by toggle foreground/background. (Surprisingly the eraser is ignoring the mask and erases the bitmap, logically it should unerase while the mask is the active canvas.)

 

But the mask not really a replacement for the eraser, because

a) extra layer is required

b) switching of color to erase/unerase is cumbersome (hotkey available?)

c) most important: that tool is incompatible to the automatic eraser tools, such as the background eraser.

 

It would be good to be able to paint into the alpha channel - to unerase!  At least a short while after the erasing/automatic erasing as long as the non-alpha pixel are still intact. (they are probably lost after load/save)

 

I would favor this behavior with the eraser  

a) I can select a brush as well

b) use a hotkey (Alt?) to unerase (=restore the alpha channel)

[whitehead]

Thanks Henry - my Affinity Photo trial has expired at this point so I can't quite give it a flight test but I think you know precisely what I'm talking about. I guess Julian either didn't see your reply or hasn't had chance to try out the select Eraser/select Brush technique - I know it works, however, as the Affinity team were kind enough to reply to me the other day via email, a nice bit of all-too-rare customer support!

[Julian23]

This "erase with any brush" / "paint with aplpha" is easy done in Affinity. First select the eraser tool, next select the paintbrush you use, and off you go! Switch between keyboard E and B to erase or paint. :)

 

 

Sorry - I cannot reproduce the desired behavior - with I can paint any color and with [E] I can erase - but I cannot "unerase" with the brush.

 

This means I cannot use the brush to restore image content which was removed by the eraser.

Other programs, such as Photoline can do this. There you can use the eraser to remove bits from the alpha channel and the brush to add it - without changing the R-G-B channel.