The .xcf you posted (low res ? print size 1.4" x 1" @ 300 ppi) is 32 bit floating precision, so first thing is change back to 8 bit using Image -> Mode -> Precision
Then you can select and fill, as PixLab indicated (or whichever way you favour)
However, my guess is at some stage it was a vector or at least had vector shapes. Not impossible to re-create, a little tedious, helps if you know the font but with a bit of tracing, attached as a scaleable vector graphic (svg) Why this format ? Open in Gimp at any size / resolution and maintain quality for sending off to a printer.
If you include the paths during import, then easy to change colours to whatever you require. example: https://i.imgur.com/KYTHmTd.mp4
Edit: I did find a match for the font: https://www.wfonts.com/font/nova-mono
Still a SVG with the text as a path. An improvement on the traced version.
Then you can select and fill, as PixLab indicated (or whichever way you favour)
However, my guess is at some stage it was a vector or at least had vector shapes. Not impossible to re-create, a little tedious, helps if you know the font but with a bit of tracing, attached as a scaleable vector graphic (svg) Why this format ? Open in Gimp at any size / resolution and maintain quality for sending off to a printer.
If you include the paths during import, then easy to change colours to whatever you require. example: https://i.imgur.com/KYTHmTd.mp4
Edit: I did find a match for the font: https://www.wfonts.com/font/nova-mono
Still a SVG with the text as a path. An improvement on the traced version.