Making an alpha channel in Photoshop

T

The Asylum

The poster/overlay tutorial tells you what to use as an alpha channel.... just not how to set one.

But anyway, it's like this:

Layer 1 is an image. Layer 2 is black, obviously what I want to set as a transparent alpha channel. Now what? :confused:
 

YM

LVL100 YM
aa
Dec 5, 2007
7,135
6,056
The "channels" tab

Create a normal black and white (with shades of grey for semi-transparent) (black is fully transparent) layer that represents the transparency of your image. if you use several layers to get the right transparency merge them all into one b/w layer and copy it all. (don't cut, you need to have a layer with stuff in it selected)
Then hit the channels tab next to the layers tab, hit the usual "new layer" button (only it's adding a new channel) and it should make a new channel called alpha 1
select just alpha 1 and paste your b/w image in.
Go back to layers, hide the b/w stuff so just your poster is visible (you need to re-enable the RGB channels to see stuff) then simply hit save as vtf.
 
T

The Asylum

The "channels" tab

Create a normal black and white (with shades of grey for semi-transparent) (black is fully transparent) layer that represents the transparency of your image. if you use several layers to get the right transparency merge them all into one b/w layer and copy it all. (don't cut, you need to have a layer with stuff in it selected)
Then hit the channels tab next to the layers tab, hit the usual "new layer" button (only it's adding a new channel) and it should make a new channel called alpha 1
select just alpha 1 and paste your b/w image in.
Go back to layers, hide the b/w stuff so just your poster is visible (you need to re-enable the RGB channels to see stuff) then simply hit save as vtf.

Don't take this the wrong way Youme, but..... I want to have your babies.
 

Altaco

L420: High Member
Jul 3, 2008
484
120
What you want to do is duplicate your image, place it on a layer below, and smudge the bottom layer outward a bit. Or just use the layer settings to make the alpha mask slightly smaller.
 

YM

LVL100 YM
aa
Dec 5, 2007
7,135
6,056
I always seem to get a slight white trim to mine, regardless of what I do.

make it float above a layer that is the same colour as thevery edge of the poster, that way the white trim will still be there, but be exactly the same colour as the poster itself, making it invisible
 

Pocket

Half a Lambert is better than one.
aa
Nov 14, 2009
4,694
2,579
I always seem to get a slight white trim to mine, regardless of what I do.

You don't happen to (a) be trying to resize the image while it's still in multiple layers, or (b) have antialiasing turned on in the paint bucket or selection tool, do you?