I got a question on deviantart about how I get my sketches to scan so nicely. If you’ve ever scanned a pencil sketch especially a light one, and then tried to bump up the contrast by playing with levels or contrast in photoshop then you know the results usually leave a lot to be desired.
Here’s what I do to give my sketches contrast without losing much quality.
I’m going to use a non-photo blue pencil sketch to demonstrate, since these can be especially tricky to get good results from.
Scan at a high DPI, I normally scan at 600DPI.
You will probably get something that looks like this:
ie. barely visible.
Next, select the whole canvas (ctrl+A) and then copy (ctrl+C) and paste (ctrl+V) a couple of times so that you have the same image in three or four layers.
Next set each layer above the background to multiply:
Flatten the image now and you should have something like this:
If you’re scanning normal pencil you can experiment with adding and multiplying more layers, or playing with the levels to darken the lines at this point.
Since I’m working with colored pencil, my next step is to adjust the hue (ctrl+U) to add more contrast:
Simply move the hue slider to wherever it looks best to you.
After adjusting the hue I adjust the levels to bring the white of the paper back up, and I’ll have this:
If you play around with the hue and levels a little bit you can even get a pretty decent monochrome from “non-photo blue” sketches:
Some people also like to add a very small amount of gaussian blur to smooth the lines a little bit before resizing. Note all of these steps produce better results when performed on an image before it has been resized. Only resize after you’ve fixed the contrast!
I hope that helps anybody who’s been looking for ways to get good quality images out of light pencil sketches.
