LIS 523 - GIMP Lab

This lab will give you some hands-on experience with using GIMP 2.2 to manipulate photographic images. Instructions will emphasize keyboard shortcuts and menu items, but you may also note that there is a pallette of tool buttons in the main window.
  1. Download your picture from the FIMS intranet site. (This should be a JPEG file, typically 150x150 pixels and about 4 KBytes.)
  2. Run GIMP 2.2.
  3. Open your picture file by selecting "Open" from the main "File" menu. In the "Open Image" dialog, navigate to the right directory, click on the filename, and then click on "Open". (One glitch in GIMP is that it will fail to display directory names starting with .; but you are unlikely to encounter this.) The image from the file should now appear in a separate window.
  4. To enlarge the image, press the + key on the main keyboard (Shift-=, not the + on the numeric keypad) (press the hyphen key if you want to shrink it). To see the entire image at once, you can then enlarge or maximize the window in the normal Windows fashion.
  5. Select "Tools"+"Color Tools"+"Color Balance". In the "Color Balance" dialog, try adjusting the color levels to about 32 on the cyan-red scale and about 16 on the magenta-green scale, using either the spin edits or the sliders. This will give the image a warmer tone. You can select "Shadows", "Midtones", or "Highlights": the results are fairly similar. Click on "OK".
  6. Select "Tools"+"Color Tools"+"Hue-Saturation". In the "Hue-Saturation" dialog, lighten the image by setting the "Lightness" value to 32. Click on "OK".
  7. Select "Tools"+"Color Tools"+"Posterize". In the "Posterize" dialog, set the levels to 16. Click on "OK".
  8. Select "File"+"Save As". Save the file under the name 523gim01.jpg. In the "Save as JPEG" dialog, set the quality to about .80 and click on "OK". Close the image window.
  9. Open the original image file as before.
  10. To scale the image, select "Image"+"Scale Image". In the "Scale Image" dialog, select "Percent" instead of "Pixels" from the top drop-down list, change the "Width" value to 75. When you tab out of that field, the ratio may adjust slightly, and the Y ratio will adjust to fit (unless you have turned off ratio linking by clicking on chain icon to the right). Click on "Scale".
  11. Select "Tools"+"Selection Tools"+"Ellipse Select" or press the E key. Drag out an elliptical selection box around your picture. Select "Select"+"Invert" or press Ctrl-I. You should now have selected everything except the eliptical region. To feather the selection, select "Select"+"Feather"; in the "Feather Selection" dialog, set feathering to about 50 pixels and click on "OK". Select "Edit"+"Clear" or press Ctrl-K (normally, this would do what you would expect, clear the selection; but, because you have just selected to feather, in this case the clearing is fuzzy). You should now have a cameo with a feathered border. Click outside the image to cancel the selection and work again with the image as a whole.
  12. To rotate the whole image, select "Select"+"All" or press Ctrl-A and select "Tools"+"Transform Tools"+"Rotate" or press Shift-R; in the "Rotate" dialog, adjust the center point if you wish, set the angle to about 5 degrees, and click on "Rotate". This will leave a "floating" rotated selected area. For some reason, "Select"+"None" does not work at this point, and clicking outside the image just brings up the "Rotate" dialog again; so, you should first select a selection tool and then click outside the image to cancel the selection.
  13. To add some text, select "Tools"+"Text" or press T; click in the white space near the upper left; in the "GIMP Text Editor" dialog, type your name and click on "Close". Select "Dialogues"+"Tool Options". You should now see a "Text" panel at the bottom of the main GIMP window. Use this panel to select a serif font, such as Times new Roman, and to adjust the size to 8 points. Then return to the image window and select "Image"+"Flatten Image" to cobine the new text layer with the image layer.
  14. To pick a color, select "Tools"+"Color Picker" or press O and then click on a pixel in the image that shows the desired color. Make a note of the color's hex triplet in the "Color Picker" dialog and click on "Close". Repeat this process for three thematic colors in the image.
  15. To smudge part of the image, select "Tools"+"Paint Tools"+"Smudge" or press S; drag the mouse across the area that you want to smudge. Before smudging, you may want to adjust the brush size: select "Dialogues"+"Brushes" or press Shift-Ctrl-B; in the "Brush Selection" dialog, click on the size and shape of brush that you want and then close the dialog.
  16. Select "File"+"Save As". Save the file under the name 523gim02.jpg. In the "Save as JPEG" dialog, set the quality to about .80 and click on "OK". Close the image window.
  17. Open the original image file as before.
  18. To apply a filter to the image, select "Filters" plus the specific kind of filter, set any options that you wish in the dialog that comes up, and click on "OK". Save the results of applying one of the "Artistic" filters as 523gim03.jpg.
  19. To apply a filter to a part of the image, first select the part that you wish to be affected then select "Filters" and proceed as above. Save the results of applying a blur (except "Tileable Blur", which does not work correctly) to the area around an elliptical area as 523gim04.jpg.
You should now have three hex triplets for thematic colors plus 4 files, all modified by the GIMP: (1) in warmer colors, posterized, (2) reduced in size, with a cameo effect, tilted by 5 degrees with your name in the upper left, (3) showing an artistic filter applied to the whole image, and (4) showing blurring of the area around an ellipse. Submit your three hex triplets by e-mail with the graphic files as attachments.

Last updated September 1, 2005.
This page maintained by Prof. Tim Craven
E-mail (text/plain only):
Faculty of Information and Media Studies
University of Western Ontario,
London, Ontario
Canada, N6A 5B7