Coloring Cat's Goddess (1)
This is selected translation from my article in book "HOW to Digital ART Vol.1" (Kadokawa Co. 2001)

1-1
First, I scan in my drawing art, which cleaned up with 0.5 mm mechanical pencil on tracing box. The scanning condition is 300 ppi resolution of gray scale. You may be able to scan at higher resolution (e.g., 600 ppi). But you should keep these in mind that color mode of the scanned data must change to RGB and many layers will add later. "Heavy" data will slow down response of your computer. In this case, the actual data size is 2800 x 5700 pixels and it seems to be enough for expected final print size (about 30 cm height).

1-2
Then I open the scanned data with Photoshop and correct contrast of the picture by selecting Image->Adjust->Levels from menu. In dialog box, I change a black point level (black triangle) to 100 and a white point level (white triangle) to 200. These make the scanned paper color complete white and make the pencil line sharper and clearer. In addition, I change a gamma value (gray triangle) to 0.9. By this change, the detail of the picture a bit thicker and avoidable being faint when the finished data size will be reduced.

1-3
After making the contrast higher, traces of eraser and other "stains" of paper appear as small but clear dots. I carefully erase this garbage with Eraser tool. Fainted lines are also corrected with Airbrush tool at this point but you have to mind not to make the line too fat.

1-4
Cleaning up and correction of lines are finished. This data is still in gray scale mode at this point and saved in Photoshop format (.psd).
When you scan your line art at high (above 300 ppi) resolution, sometime the rough appearance of the scanned line may make you nervous. But there is no need to worry about it. Any beautiful ink line looks rough when you scan it in high resolution and magnify on screen.