View Full Version : Question about Photoshop for Sci-fi Bookcover

05 May 2011, 11:21 PM

I have a question about Photoshop. Maybe this is not the right place but I searched for the answer in the forums but I couldn't find it.
So here it is:
How can I make sketchlines white?
If I want to change the colors of my sketchlines I use cmd+U but I can't make the lines white...then they will dissapear. I tried to make a mask of it and inverse it, but this doesn't work. Maybe I have to make the selection of the hair 'negative'.
Or do you have a great tip to help me?
I want to work on it tomorrow, so hopefully somebody can help me a.s.a.p. Thanks a lot if you give me some advice..

Bbcode: (
Color_blue ( by marjoleincaljouw (, on Flickr
Bbcode: (
cleansketch ( by marjoleincaljouw (, on Flickr
I made the sketch with graphite and blue pencil because I thought it was easier to change the color this way in Photoshop, or I could have a better softer result.

05 May 2011, 02:02 AM

Assuming you have a higher resolution version of the sketch, and have more details of the blues lines, try this:

Use Select Range to mask the blues. It's in your "Select" menu, if you haven't used it before, learn how, it's excellent for isolating specific colors and ranges of color. It takes some practice, however. I use it all the time to create a base mask of intricate images, like hair, and then go in and tweak the selection by hand. Saves a TON of time!

When you're happy with it, save the selection as a channel in the colored document, or if you have both images in the same file.

Apply a black and white layer to the whole piece, and use the mask channel to create mask for the B&W adjustment layer. (Thus, you mask out everything but the blue lines.) Adjust the settings so the blues are dark, black if you can.

Then, apply an invert layer over that, with the same mask. You may need to tweak it to get pure white, and do some intricate masking, but it should work.

05 May 2011, 02:35 PM
Hey BillyWJ,

Thank you for the quick answer! I used color range several times, but I don't get it right with the blue sketchlines.
Let me show it here... (
Afbeelding 14 ( by marjoleincaljouw (, on Flickr
When I tried it with another sketch done with black graphite it works perfectly!
I did it like this:
Select -> color range
Fuzziness on 65.
Selection preview: none.
The selection was pretty clear and I could go further with:
Image -> Adjustments -> invert.
Then color the layer with white or other colors.

But when I tried to do the same with the blue lines, it doesn't seem to work out the same...
I still think that your way is a good way, maybe it's just the blue lines.
Here sampled colors are on 200. How do you select the blue lines percisely? (
2_sampledcolors_200 ( by marjoleincaljouw (, on Flickr
I also tried to select it with "cyans" (
1_Cyans ( by marjoleincaljouw (, on Flickr
It's hard to select the blue colors very percisely, because the blue tones are also in the background, although I leveled the original sketch. (
3_Bad_selection ( by marjoleincaljouw (, on Flickr
This (below)was definitely the best selection I could get, but it was automaticly, so I don't know how Photoshop calculated this. Or how the fuzziness was selected. (
4_Better_selection_automatic ( by marjoleincaljouw (, on Flickr
I made a mask on top of the sketchlayer to erase the blue parts.
I added a mask to the layer with the white color.
The hair looks still a little fuzzy as you can see...But I think this is the best I can get.
What do you think? (
6_Darkhairparts ( by marjoleincaljouw (, on Flickr
Close-up on the fuzziness... (
7_Fuzziness ( by marjoleincaljouw (, on Flickr

05 May 2011, 01:09 AM
Duplicate the sketch layer on top, invert it, reduce saturation to zero, use surface blur to remove background noise in the black regions, then switch blend mode to "lighten" and adjust "Levels" until the white lines shine through. Use a brush and manually blot out the linework you don't want to be white. Then tweak brightness/contrast etc. Finally merge the layer back down. Of course, there is no magic button to transform linework into a finished the hair should be repainted.

05 May 2011, 03:17 PM
Stuh - your solution has a lot of grey in it, which I think is not what he wants.

M-J-C - looking at your screen shots, the problem is the source is too low res. I've used Select Range for some very specific masking, but I was working on very high res files.

What size file do you work on? I generally start at 12 x12 @600 dpi, which might be overkill for a lot of people here, but you should be working at 300 dpi minimum, at a decent full size, like 8x10. I work in the publishing world along with being a designer and illustrator, and 300 dpi @ print size is mandatory.

Can you rescan your original sketch at a higher res? That would help. You can then blur and smooth the mask later to soften it up.

I played around with it a little after I posted. There's always a couple ways to do things in Photoshop, but I didn't get any better results, the resolution was just too low.

Honestly, at this point, What you've posted is as good as it's going to get, but you can try blurring it, and use a soft eraser to clean it up. I know it's going to be a lot of work, but I think the piece is worth it, no?

I'll be honest, too...I don't mind the blue lines. :)

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