Alpha masking scans in Gimp and PS

[Jaxilon]

I figured something out, oh, I don't know about a month ago, that I should have known about a year ago. I wouldn't say anything except it might help someone else coming along the same path.

If you use a scanner to import your drawings you always have that annoying white background that isn't much help. Personally, I like to strip all my lines off of that background and put them on their own transparent layer. This used to involve me trying to select all the white areas and delete them. That always left a bit of white fuzz around the actual pencil lines. I was left with having to delete by hand or use the grow tool and shave off portions of my sketch. Alas, what a noob!

'Color to Alpha' is your friend. Now it may have been explained at some point but I missed it until I stumbled upon it. By selecting "Colors>Color to Alpha..." you can strip out every bit of white that is left over from your scan. It's very clean and does a wonderful job especially if you have already tweaked the contrast of your image. If you had other colors you wanted to be rid as well, just select the proper color within the "Color to Alpha" pop-up and bang, you are done.

It makes me wonder what else I'm doing the hard way. Sheesh!!

[jtougas]

Brilliant.

[Jaxilon]

LOL, I feel like an idiot but oh well. If you can't laugh at yourself you deserve the ulcer coming your way.

[Gidde]

if you don't want to actually delete the white, you can also just change that layer's mode to multiply, or grain merge will increase the contrast but still let you see through the scan. Thanks for posting; it took me awhile
to figure that out when i started as well, and i'm sure we're not the only ones

[Ghostman]

Alternatively you could just set the layer blend mode to 'Multiply'.

EDIT: Ninja'd by Gidde!

[Gidde]

Mwahahahahaha.

[Hai-Etlik]

My preferred method is to use inverse of the image as a layer mask.

[ravells]

My preferred method is to use inverse of the image as a layer mask.

OMG that's genius!!! So simple and it never occurred to me and I've never seen it suggested anywhere in 9 years of using photoshop! Then all you need to do is merge the masked image with a transparent layer below to 'commit' the transparency.

I'm going to beat you with my rep stick till you die, Hai-Etlik!!!

[Hai-Etlik]

OMG that's genius!!! So simple and it never occurred to me and I've never seen it suggested anywhere in 9 years of using photoshop! Then all you need to do is merge the masked image with a transparent layer below to 'commit' the transparency.

I like to leave it as a mask in case I wanted to say recolour or otherwise edit the lines. That's the primary reason I favour it over using multiply.

[RobA]

My preferred method is to use inverse of the image as a layer mask.

That is also the easiest way to turn a B&W image into a mono-tint. After creating the layer mask flood fill the layer with a desired colour.

-Rob A>