Feature request: color correction option for masks

[surajrv6]

In photoshop, there is an option where it is possible to curve adjust or level adjust the black and white values of the masks. This comes handy when I need to adjust the alpha of a 3d render. I miss this feature a lot.

[Beatriz Castillo]

I second this request  It's a must when working with mask and luminosity mask. For now I load the mask (alpha channel) as grey, apply curve or level and rasterize it like mask again. But this option can save a lot of time.

Edited March 2, 2021 by Beatriz Castillo

[xuxing]

aye aye, I need this too.

[smadell]

This same technique will also work with Curves.

[Beatriz Castillo]

The main idea of this request is to refine a luminosity mask. The level or curves use is the first step. After that you will apply brush with blend modes like overlay  to the combined mask and level or curve for get the right mask. With the smadell tip you can modify the luminosity of the mask using curves or levels, yes, but you lost the effect when try combine with the mask or you can't see what is happening if use a brush with a blend mode to refine the final mask.  For now I load the mask (alpha channel) as grey pixel layer , apply curve or level, work with brush set as overlay to get the right mask  and rasterize it like mask again. 

[kirk23]

What's the problem with that ?    I thought it always been possible:

 

 

Contrary to Phs you can make a huge non-destructible mask editing only stack here.   Well, In Psh it's possible too  but you need groups clipping for that. Not a mask technically.

Also you can "release" the mask,  edit it separately, then make it back with  "mask to bellow" again 

 or you can put embedded document in a mask and if it's copy stay in the  main layer stack somewhere  you could edit that embedded doc  with the mask updating interactively

 

ps, the black fringe my example shows  is not a mask issue. it;s  8-bit per pixel  typical sRGB issue.   Switch the doc to linear 32 -bit and  and it will be correct.  Psh has same issue.

mask stack.afphoto

[surajrv6]

1 hour ago, kirk23 said:

What's the problem with that ?    I thought it always been possible:

 

 

Contrary to Phs you can make a huge non-destructible mask editing only stack here.   Well, In Psh it's possible too  but you need groups clipping for that. Not a mask technically.

Also you can "release" the mask,  edit it separately, then make it back with  "mask to bellow" again 

 or you can put embedded document in a mask and if it's copy stay in the  main layer stack somewhere  you could edit that embedded doc  with the mask updating interactively

 

ps, the black fringe my example shows  is not a mask issue. it;s  8-bit per pixel  typical sRGB issue.   Switch the doc to linear 32 -bit and  and it will be correct.  Psh has same issue.

mask stack.afphoto

Can you try adjusting the alpha of this image? I am not able to adjust alpha
https://us-browse.startpage.com/av/anon-image?piurl=https%3A%2F%2Fi.pinimg.com%2Foriginals%2F19%2F8d%2Fae%2F198daeda14097d45e417e62ff283f10e.png&sp=1615123961T5ebf27b8b1a9db51a2710103956de568b73935130237103eebcd5c9491b162cc

[NotMyFault]

1 hour ago, surajrv6 said:

Can you try adjusting the alpha of this image? I am not able to adjust alpha
https://us-browse.startpage.com/av/anon-image?piurl=https%3A%2F%2Fi.pinimg.com%2Foriginals%2F19%2F8d%2Fae%2F198daeda14097d45e417e62ff283f10e.png&sp=1615123961T5ebf27b8b1a9db51a2710103956de568b73935130237103eebcd5c9491b162cc

Hi surajrv6,

just as kirk23 explained:

1. Open the PNG file from your link (you must use "save link as", do not copy the image from browser)
2. add a "levels" adjustment
3. switch from "master" to "alpha" channel
4. drag any of the sliders
5. check with "info" panel and see that A will change

[surajrv6]

13 hours ago, NotMyFault said:

Hi surajrv6,

just as kirk23 explained:

1. Open the PNG file from your link (you must use "save link as", do not copy the image from browser)
2. add a "levels" adjustment
3. switch from "master" to "alpha" channel
4. drag any of the sliders
5. check with "info" panel and see that A will change

Hi NotMyFault,

Thank you for the detailed explanation. Adjusting the luminosity of the mask is working now. But there is a limitation here.. What if I want to test the transparency behind a background? or with all the layers turned on? It Will not work in that case. I just tried putting a black BG to see the how the mask look. the adjustment layer just adjusts the transparency (alpha) of all the layers

 

Also attaching the affinity photo file

clouds.afphoto

[kirk23]

3 hours ago, surajrv6 said:

What if I want to test the transparency behind a background?

see in file I posted earlier , just put the levels on top of an object mask.   Or rather put the mask beneath levels

 

 

ps. also you can use erase blending  to replace the whole idea of masking

 

and use  blend option to adjust the transparency without levels at all .

It's same as if you would make a clipping group in Photoshop  and use "blend if"  sliders   .

 

erase as mask.afphoto

[surajrv6]

1 hour ago, kirk23 said:

see in file I posted earlier , just put the levels on top of an object mask.   Or rather put the mask beneath levels

 

 

ps. also you can use erase blending  to replace the whole idea of masking

 

and use  blend option to adjust the transparency without levels at all .

It's same as if you would make a clipping layer in Photoshop  and use "blend if"  sliders   .

 

erase as mask.afphoto

Hmm... erase blending option is something I was looking for. Thank you!

[surajrv6]

7 hours ago, kirk23 said:

see in file I posted earlier , just put the levels on top of an object mask.   Or rather put the mask beneath levels

 

 

ps. also you can use erase blending  to replace the whole idea of masking

 

and use  blend option to adjust the transparency without levels at all .

It's same as if you would make a clipping group in Photoshop  and use "blend if"  sliders   .

 

erase as mask.afphoto

Consider this example. Suppose I want to fix the alpha (mask) of this sphere. (I have attached the image for anyone who would like to test) I want to remove the shadow alpha near the border so that when I place the image in a presentation I dont get this sharp edge on white BG

This hard edge. I know this can be fixed using brush but photoshop makes it way easier by allowing to edit alpha. I just adjusted the levels. Below is the photoshop result. Now the erase blend does not work here because it works on all color and not just the mask's luminosity. I know this is possible with adjustment layers. But also consider that there are many solid layers stacked

[Max P]

Hi surajrv6,

 

Put a pixel layer  on the top, put it in erase mode

paint on the edge witl a brush about 22 % opacity, (you can  adjust with %)

Also you have with level or curve, alpha option

[surajrv6]

I just realised today that even Gimp allows to level correct alpha mask