[Gimp-user] transparency puzzle

[Roy_Pittman <forums gimpusers com>]

I am presently unable to do something I have done many times. It is embarrassing
but:
1) I have a scan that is in grayscale. I want to keep the black "text" and make
the white background transparent.
 2) I t has only one layer.
3)I have added an alpha channel.
4) The "color to alpha" remains grayed out!
5) I am stuck here. I want to send the background color (approximately white) to
alpha channel.

I have sent a screenshot. I am obviously missing something. Any suggestions?

Attachments:
* http://www.gimpusers.com/system/attachments/1049/original/transparency_puzzle.png

-- 
Roy_Pittman (via www.gimpusers.com/forums)