Graphics-editing software often separates images into single-color channels, allowing users to alter the balance of specific primary colors within the image. Like many graphics software titles, GIMP uses red, green and blue as its default primary colors. In addition to these color channels, a fourth channel known as an "alpha" channel can be added to images. The alpha channel represents transparency within an image and is used to make certain portions of the image appear transparent in the final saved image.
Instructions
1. Launch GIMP. Open the image you wish to add an alpha channel to or create a new image.
2. Open the "Image" menu. Mouse over the "Mode" entry to access the GIMP mode settings menu; click "RGB" to change the mode so that red, green and blue are the primary colors for the image if any other mode setting is being used.
3. Open the "Layer" menu. Mouse over the "Transparency" entry to access the GIMP transparency menu and click the "Add Alpha Channel" option to add an alpha channel for the image.
4. Click the "File" menu and then select the "Save As..." option. Save a copy of the image as either a .tga file or .png file, as both of these image formats support the use of alpha channel transparency. Most other formats will delete the alpha channel upon saving.
5. Click the alpha channel to select it. Erase portions of the image with the "Eraser" tool while the alpha channel is selected to create transparency in those areas. Save your work frequently to protect yourself from mistakes, software crashes or other problems that could result in loss of data.
Tags: alpha channel, primary colors, access GIMP, entry access, entry access GIMP, green blue
