How do I remove black lines from an illustration / artwork?

Question

Hi all! First ever post on this great site so, please be kind :-)

I have a panoramic shaped image of buildings that I have studied which I created using ink on paper. The original piece is just that: black ink outlines on white paper.

Using Photoshop (after scanning the whole piece) I have separated out each building, printed them separately, and coloured in (as seen in the image).

In order to print as one connected piece, I now want to add the colour work, piece by piece, back into the scanned linework layer I have in Photoshop. But, I want to add only as much of the colour work back in as possible - and NOT the black outlines. So, almost like sliding the colour underneath the black outline work.

What is the most accurate way to achieve this?

Hope this makes sense and thank you for any help with this.

Answer 1

If you wish to color on paper by hand, using the printed key line (black outline) as a guide, then the best option would be to use translucent paper for coloring such as Layout Bond.

You place the printed key line under a sheet of Layout Bond - it will show through the paper - and color. When you are done coloring, scan the colored layout bond and you won't have any key lines to deal with.

You can then add the scanned color to a layer in Photoshop under the key line layer and subsequently mask areas of color you do not want.

In short, you don't color in the key line prints. You use them as a guide.

(And alternatively, you could paint directly on layers under the key line layer in Photoshop.)

Trying to remove the key line after you've colored in everything is about 500% more work than you should be assigning to yourself.

Answer 2

To remove the black outlines it'd be easier if they were pure black (0,0,0,100) you could knock out the black channel then—I suspect though they're probably composite and so the way I'd attempt it would be to increase the image size (if the resolution's low (this makes for more accurate selection)) then go to select>color range and sample a heavy part of what appears black in your image. Toy with the fuzziness and range till your preview appears to have selected what you want. Then okay your way out. Go then to select>expand (by a pixel or two) and okay your way out of that. Next hit delete—it ought to have then removed your outlines and left just the lighter shades.