Graphics Tutorials: Scanning Line Art
As a comic artist and cartoonist, I work with scanned line art just about every day. This tutorial will explain the proper way to scan artwork and "fix" the problems that can occur in scanning.
Workflow. My typical workflow for creating artwork is as follows:
- Draw artwork in pencil.
- Ink the pencil artwork and erase the pencil lines.
- Scan the inked line art into Photoshop.
- Use Photoshop to add colors and effects.
Some artists draw their artwork directly on the computer with Wacom tablets. While I have tried it, I find my preferred method of working is draw by hand and scan. But to each his or her own. 
Penciled Artwork. So let's assume you've completed step one above... you've drawn your artwork in pencil. Some people scan in penciled artwork and colorize it. Some comic studios these days are experimenting with going straight from pencils to colors without inking, or doing the inking digitally. You can certainly try this, but I definitely prefer the strong crisp lines that come with inking. Moreover, I find that the process of choosing which lines to ink and making some lines thicker and some thinner enables me to create a more smooth, sharp result. But you can achieve different effects with pencil work.
I should also mention that some many professional comic book artists use a blue pencil, which makes it easier to remove the pencil lines later.
Inked artwork. I typically use black Micron pens with a thickness of .03 or .05 for a standard width line, .01 for fine lines, and .08 for thick lines.
I also use a brush type pen with a felt tip such as the Marvy 1314 to artistically thicken certain lines. And I usually have a Sharpie on hand for filling in large areas of black. No need to waste my good pens for large black areas. It is important to have variation in the thickness of your inked lines.
Scanning your line art. Now that you have inked your artwork, you are ready to scan. I use an Epson Perfection 1200 U scanner. (I love my scanner and can recommend Epson as a quality scanner company. I did have some serious difficulty getting it to work when I upgraded to Windows Vista.) you can scan with the proprietary software, but you can also run the scanner software from within Photoshop by choosing File > Import > [scanning software name]. For example, I choose File > Import > Epson Twain 5.
When the scanner software initially opens up, the scanner will typically do a preliminary preview scan to show you what you have on the scanner bed. While scanners software may vary, there are typically three major settings you can choose from... Line Art/Text, Black and White Photo, and Color Photo. If I click the Image Type button in my Epson scanner software, I get this dialog box.
If I am scanning a color photo or an image that I have colored by hand, I would use color photo. I once recommended using the Text/ Line Art setting because it produces a high contrast image that has only black or white pixels. But now I don't. I recommend using the black and white Photo setting for scanning line art these days.
Resolution. The resolution should be set to 300 ppi (your scanner software may call it dpi but trust me, it's PPI. A scanner produces pixels, not dots.) 300 ppi is about as high as you're likely to need if you will be adding color. You can always lower the resolution but you never want to have to increase resolution. That's a big no-no. So start with the highest resolution you think you're likely to need and lower it as necessary in Photoshop.
Clean up the scan with Levels. After you have scanned in your artwork, you will need to clean it up a little in Photoshop. Specifically, you'll want to make sure that your white background is solid white and your black lineart is solid black.
Right now, your line art will have blacks that are not totally black and whites that are not solid white. Have a look at this scan from Shanehai. Note how you can see the marker lines in the solid black areas, and that the white background isn't pure white.
You can fix this by using a Levels adjustment in Photoshop. Open the Image menu and select Adjustment > Levels or use the shortcut Ctrl L to display the Levels dialog box.
The histogram shows that you have a cluster of pixels in the darker range (the hill on the left), but they are not solid black. You also have a cluster of pixels in the lighter range on the right. To make your blacks a more solid black, drag the Black input slider (the black triangle on the left) to the right of the hill. To make your "near-whites" become pure white, drag your White input slider to the left.
As you adjust your levels, you will see the darker shades become solid black and your lighter shades become pure white.
