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.
2.5.2 Scanning Your Image
As mentioned earlier, a separate program (usually the scan program that came
with your scanner) actually processes a scan, even though you're capturing
the image within the image editing program. Because scan programs vary
according to the make and model of the scanner, the example dialogs may
be slightly different than what you will actually see on your computer screen.
To scan an image from within GIMP, select
File > Create
in the Toolbox.
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