How to Clean Up a Line Art Scan in Photoshop CS6
When you scan line art, you may need to clean it up using Adobe Photoshop CS6. You don’t want to see the background color of the paper. Often, the paper appears as a dull gray, and you may see other artifacts you don’t want, such as wrinkles or spots in the paper.
Luckily, Photoshop has a handy Threshold command that you can use to determine which tones appear as black and which are dropped altogether. You end up with a nice black-and-white line art image with all the intermediate tones removed.
Follow these instructions to clean up a piece of line art:
Open a line drawing in Photoshop.
Choose Image→Adjustments→Threshold from the menu bar.
The Threshold dialog box includes a chart called a histogram. The histogram includes a series of vertical lines showing how many of an image’s tones are represented by a certain brightness level. You can see that a relatively small number of tones are represented by a brightness value of 93, marked by the gray triangle at the bottom of the histogram.
Move the slider to the right until the tones you want to appear in the image are shown.
The more you move the slider to the right, the darker the image gets. A threshold of about 170 seems about right for this image.
Click OK to apply the modification.
Some small artifacts may remain in your image. These are spots and parts of wrinkles that are darker than the page background, approaching the darkness of the line art itself.
To clean up these slight defects, use the Eraser tool.