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Sapiento
03-23-2010, 02:57 AM
I need some help.
I used a while ago a technique in PS with Quick mask to remove the white from a black outline drawing. Something with copy and past and cut, or so. But I haven't done it for some time and even if the fate of mankind would depend on it, my brain refuses to remember how I did it. The technique didn't use any brush or lasso tool, just cut or copy in some way with the activated quick mask function at some point.

I'm not sure, but I think I read in one of the subforums about this.

Thanks in advance for any hints.

waldronate
03-23-2010, 03:15 AM
I just use the Select>>Color Range tool to select the background color (adjust fuzziness to get the whole thing) and then cut to remove it. Usually there's not too much need to do for map elements because a blending mode of multiply works well for black and white overlays.

Sapiento
03-23-2010, 03:30 AM
I just use the Select>>Color Range tool to select the background color (adjust fuzziness to get the whole thing) and then cut to remove it. Usually there's not too much need to do for map elements because a blending mode of multiply works well for black and white overlays.

Thanks. I know the technique you described, but the one I can't remember (lousy brain) worked somewhat better than this.

Daelin
03-23-2010, 04:03 AM
Background Eraser Tool?

Sapiento
03-23-2010, 04:16 AM
Thanks, Daelin. What was so nice with the quick mask method was the simplicity. Three or four clicks and the white was gone. Dammit, if I could only remember....

Daelin
03-23-2010, 05:10 AM
But the Background Eraser Tool is basically: set background color to white, 2500px brush, click once on canvas...

Sapiento
03-23-2010, 05:41 AM
But the Background Eraser Tool is basically: set background color to white, 2500px brush, click once on canvas...

I'll try it as soon as I get to my PC.

Dain
03-23-2010, 08:03 AM
I've got the same problem and find the easiest way to do it with ... Gimp
Menu Colors/color to alpha
It removes the white background and makes all transparent in 3clics
save and open with PS and do what you have to do

I wish i could do it with PS but ... not the case

tilt
03-23-2010, 09:25 AM
I'm not 100% sure I understand your question - but here goes ... try going to alpha channels (its by your layers) and CTRL click on the black channel - this should select the black colors. Then, returning to your layer you can add a layer mask for non-destructive editing or you can inverse selection and delete. :)

Ilwan
03-23-2010, 01:35 PM
http://aoi-hoshi.deviantart.com/art/Remove-White-Photoshop-Action-103785705

Photoshop action that does it nice and clean.

Sapiento
03-23-2010, 02:28 PM
Thanks, Ilwan. But my INCREDIBLE brain has finally remembered!!!:o:D
Open outline in PS > select all > cut > fill with black > quick mask > paste > disable quick mask > delete...Voila!

Oh my brain, my brain...;):D

torstan
03-23-2010, 02:47 PM
Interesting, that looks like it basically turns the brightness into an alpha channel, so the lighter the colour, the more transparent it is. So it works for white, but not if it's a black background. It also seems to grey out a lot of the image, as (unless the image is 100% black) the quickmask masks some of the coloured regions.

Another way to do something similar is:

1. duplicate layer
2. Desaturate
3. Use a levels adjustment and pull the white and the black sliders in to increase the contrast. You can use threshold, but that will give jagged edges.
4. Copy the layer (and then turn it off).
5. Add a layer mask to your original layer.
6. Option click the layer mask (your screen should now be white) and paste.

You should now have a mask that corresponds to the layer you created. You probably need to invert this to get what you want.

You can start with the red, green or blue channels instead of your full image to get some better results.

Carnifex
03-27-2010, 12:03 PM
So it works for white, but not if it's a black background.


Couldn't "Inverse" (ctrl+I) solve this?