GIMP Version: 2.8
Operating System: Windows
OS Version: XP - Windows 7
GIMP Experience: Beginner Level

List any relevant plug-ins or scripts:
Script-FU
G-Mic
Gap

List any ERROR messages you received:
None Function does something but not what I saw in the tutorials.

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Hello. I am fairly new at GIMP, so I have been learning about how it works by following online tutorials and general just playing with everything. My problem I think is with the function color to alpha. In two tutorials now the person said to use color to alpha to remove either all white or black which would have left the other colors on the clipboard. One was like a swirl of colors on a white background. The person's clipboard just showed the swirl. I tried the same thing...colors>color to alpha>set at white... and the white still showed. I am using GIMP 2.8 and the tutorials were on both 2.6 and 2.8.
Is the function broken?

Welcome to Gimp Chat.
If it is an off white that looks white, it will leave white on your layer.
Try using the color picker to identify the white you want removed and use that code. There are so many shades of white we don't notice unless we see them side by side. You can see where I used the color picker on this layer and it shows as ffffee so that will a bit of a yellow cast that looks white.

also, be sure your layer has an alpha channel and you are on the right layer. I have found this out by my own errors.

2-ton, When you are using color to alpha, you don't use an alpha channel. This filter changes it to one.

lol, I always double check to make sure I have an alpha channel but never knew I didn't need to do that! I just assumed that it wouldn't change it to alpha if it didn't have an alpha yet. I am always over-thinking things, lol

If you have a white background layer under the layer that you are trying to apply the "Color to Alpha" filter on, you will still see the white 'showing' underneath making it look like nothing happened. Look over in your layer stack to check or simply turn off the visibility of the white background layer.