I don't do a lot of image editing, but when I do, I tend to use the GIMP. It is sometimes useful to edit an image to make one colour transparent. I'm a simple chap, and one thing I often want to do, is to make non-transparent images into transparent images, whether from a digital camera or editing an existing digital image.
The stuff I found indexed by Google related to older version of the GIMP, and no longer applied. The instructions here have been tested with versions 2.2.11 and 2.2.13 of The Gimp.
- Layer -> Transparency -> Add Alpha Channel.
- Select -> By Colour. (although you could use other selects if you want a different effect)
- Click on the colour you want to become transparent. The selection is highlighted with some dashed lines.
- Edit -> Clear
- Save the file as GIF or PNG.
There are two ways to achieve Select -> By Colour and the like; you can right-click on the image, and choose Select from the menu, then By Colour from the menu which opens up from there. Alternatively, you can choose Select from the menu bar at the top of the image, and then choose By Colour from that menu. The same goes for all the underlined text above.
What did you say? An example? Oh, okay then....