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Fixed Aspect Ratio Crop Using GIMP

fixed aspect ratio cropAspect ratio is the proportional relationship between the width of an image and its height. All images before print should be cropped to the output aspect ratio. If you simply capture a photo and print without properly crop it, you may get unexpected stretched or cropped result done by the system automatically.

The image below simulate the automatic stretched result of a scanned 8R-sized photo (A) to be printed on 4R size output (B):
simulation of photo printed with auto stretching by system

The image below simulate the automatic cropped result of a scanned 8R-sized photo (A) to be printed on 4R size output (C):
simulation of photo printed with auto cropping by system

Table of common sizes’ aspect ratio:
(may be varied in some countries)

ANSI A 17:22
ANSI B 11:17
ANSI C 17:22
ANSI D 11:17
ANSI E 17:22
Arch A 3:4
Arch B 2:3
Arch C 3:4
Arch D 2:3
Arch E 3:4
Business Card 7:4
Credit Card 27:17
Paper A0 – A10 1:1.414214
Paper B0 – B10 1:1.414214
Paper C0 – C10 1:1.414214
Paper Fanfold 17:24
Paper Folio 1:1.5719
Paper Junior Legal 8:5
Paper Ledger 17:11
Paper Legal 17:28
Paper Letter 17:22
Paper Quarto 9:11
Paper Tabloid 11:17
Photo 3R 10:7
Photo 4R 3:2
Photo 5R 7:5
Photo 6R 4:3
Photo 8R 5:4
Photo 10R 6:5
Photo 11R 14:11
Photo 12R 5:4
Screen VGA 640 x 480 4:3
Screen WVGA 768 x 480 8:5
Screen SVGA 800 x 600 4:3
Screen XGA 1024 x 768 4:3
Screen WXGA 1280 x 720 16:9
Screen WXGA 1280 x 800 8:5
Screen SXGA 1280 x 960 4:3
Screen SXGA 1280 x 1024 5:4
Screen HD 1366 x 768 16:9
Screen UXGA 1600 x 1200 4:3

 

How to Do Fixed Aspect Crop Using GIMP

Before you do it, you need to know the aspect ratio of the print output or the target screen resolution. If you can’t find it on the table above, you need to measure the width and height of the output size. For example, if the output size of the image is 180 mm x 150 mm then the aspect ratio is 180:150.

Start the GIMP, here I’m using GIMP 2.6.11. Choose Crop Tool (Shift+C key). On the option setting, tick the “Fixed:” and make sure “Aspect ratio” is being selected. Put the aspect ratio on the box below it. You may choose to switch between “Portrait” and “Landscape” layout by clicking the small icons beside it. Use your mouse to click and drag the area you want to crop, double click to finish it.

Fixed Aspect Ratio Crop - how to tutorial

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