|When you scan pencil drawings, sometimes the scan will turn up too light. We will sometimes remove artwork if the linework is too light so be sure to adjust the image so that the artwork can be easily seen.|
Doing this in GIMP is a very simple process. Start by opening your file by going to File > Open and navigating to your image file. Below is our light pencil drawing example:
The first thing you should try is the auto image adjustment capabilities of GIMP. Start by going to Colors > Auto > Normalize in your artwork window:
In most cases this will work beautifully on pencil work as shown below:
When that doesn't yield ideal results, try doing some manual adjustments. Go to Color > Levels... Adjust the ▲ sliders in the Levels dialog box to try and get the darkest colors even darker. You'll have to experiment with the sliders until you get something that looks good. I usually like to drag the leftmost input level far to the right and drag the right most slider to the left a tad as shown below. This makes the lines darker and takes out some of the pencil smudging.