If it's that you want a screenshot with a transparent background, something you can try is to export to .ai format with the "Shaded background" option turned on.

The shaded background will be a PNG image with a transparent background that will be saved alongside the .ai file. You can just take the .png and delete the .ai file.

That will also happen with SVG or PDF export as well, except for PDF the pixel data for the shaded background image is contained inside of the PDF and not as a separate .png file.

- Michael

An Alpha is not a grey level image ?

Hi Pilou,

re:
> An Alpha is not a grey level image ?

Usually "alpha" is transparency information that can be stored in an image in addition to color image data.

There are often tools or modes that can show you the alpha channel temporarily as a grayscale image as another way to work on it though.

- Michael