Image Processing Reference
In-Depth Information
In European countries, the resolution for print output is measured in
lines or dots per centimeter. For our image, let´s select a target resolution of
60 dots per centimeter, which is multiplied by 2.54 to convert it to dpi. The
other settings remain the same.
Calculation by the formula:
• Printer resolution (selected) for 1 is 60 dot/cm; for 2 it's 60 dot/cm
• Resolution (calculated) for 1 is 60 × 2.54 = 150 dpi; for 2 it's 60 × 2.54 =
150 dpi
• Scaling factor for 1 is 8 in: 0.8 in = 10; for 2 it's 10 in: 8 in = 0.8
• Scanning factor (selected) for 1 is 2; for 2 it's 2
• Scanning resolution for 1 is 150 dpi × 10 × 2 = 3000 dpi
• Scanning resolution for 2 is 150 dpi × 0.8 × 2 = 240 dpi
2.5 Scanning and Editing an Image
2.5.1 The Procedure
• You decide you want to scan an image and import it into GIMP.
• The image is tilted, so you need to rotate it to make it upright.
• Next, you want to remove the moiré effect (using the Gaussian Blur filter)
and correct the contrast and the brightness (using tonality correction
and curves).
• You'll save the image in a high-quality format using the name miami-
impro .
• Finally, you'll create a copy of the image for use on the Internet and email,
so you'll lower the resolution and save a copy in a compressed JPEG file
format.
I'll also provide an overview of the functions in the Image > Colors menu
item.