gimp question

If I were you I'd covert it to 24b colors, apply some blur filter, then convert it back to 8b

Try using some of the filters, I think there is one to soften edges. If not then you could use some blur effects as Raduprv mentioned.

Blurring isn't the same as antialiasing, but I don't think you'll be able to do any better unless you take a large source image and reduce it.

One trick might be to convert it to RGB, use select region by color, click on something black, selection to path, path to selection, create a new white layer, set flood fill to fill then entire selection, and fill it in black. This will probably create a horrible mess if your image uses dithering, though, or you have really thin lines.

Example:



On one hand it introduces some artifacts of its own, but on the other, it isn't blurry.