This tutorial will discuss how to make color fixes using the GNU Image Manipulation Program, otherwise known as GIMP. Quite often you will take a great shot, but the colors may appear faded or a bit too much contrast. The problem with many of the commercial photo editing packages is that it applies universal correction to the entire photograph. Sometimes this works well, but other times you are left with less desirable effects after applying the correction. GIMP is very well suited to manage this problem by using layers to apply color correction. In this tutorial we are going to make some simple color corrections by using layers, making a selection, adjusting colors using curves, flattening the layers, and saving a final product. Does this sound complicated? It is actually much easier than it sounds.
1. Start the GIMP application.
2. Once GIMP is loaded, select FILE from the menu the click OPEN. Locate a photograph that you would like to make color corrections. I am going to use a portrait taken outdoors for the purpose of this demonstration, so it may be beneficial to find a similar photograph to work with.
3. We don’t want to work with the original version of the photograph, so we are going to duplicate the layer by selecting LAYER from the menu bar, then DUPLICATE LAYER. You should see two thumbnails of your photograph on the right side of the screen in the floating box.
4. Select the lasso tool from the toolbox; it is the icon toward the top that looks like a rope. We are going to create an exclusion area around my subject’s face since I don’t want to alter his complexion; I only want to adjust the dark colors.
5. With the lasso tool selected, drag the mouse around the desired area you want to exclude from the adjustment. Try to get as close to the edges as possible. You will need to end at the starting point in order to complete a full path. You will know you have it right when you have a “dancing ants” selection around the desired area.
6. If we were to make any adjustments now, the only area that would be altered would be the selected area we drew. Since we want to make adjustments to everything except our selection, we must invert our selection. We do this by selecting SELECT from the menu bar, then INVERT. You won’t notice anything, but what happened was the selected area was swapped with the unselected area. Now we can make changes and the subject’s face won’t be altered.
7. Open the curves tool by selecting COLORS from the menu bar, then CURVES.
8. Now, select tow or three points on the graph and move the points up and down until you are satisfied with the results. Select OK when you are happy with your corrections.
9. We can now deselect our previous selection by choosing SELECT from the menu bar, then NONE.
10. Now we can “flatten” our layers so we can save our final product (you cannot save a layered image to a transportable file, such as.JPG when there are active layers). Select IMAGE from the menu, then FLATTEN IMAGE.
11. We can now save the file by selecting FILE, then SAVE AS (you may want to save the image to a new file rather than saving over the original file). You will be given an option to select the quality of the file you want to save. Naturally, the higher quality will be a larger file. Make your choice, then select SAVE.
That’s it, you have successfully opened an image file in GIMP, duplicated a layer, made a selection, inverted the selection, adjusted the colors, flattened the image, and saved the image to a new file. If you have used Adobe Photoshop in the past, then this process may have been familiar to you. You will find there are thousands of tutorials available on the Internet for Photoshop, but very few for GIMP. Once you become more familiar with the application, you should be able to apply the tutorials you find for Photoshop to GIMP with ease. Now, take a few minutes to repeat this tutorial until you are able to do it on your own without referring back to the instructions.
Good luck and enjoy using GIMP.