Lots of jpeg artefacts. The image maybe exported at low quality / scaled up from a tiny image.
Try:
1. Duplicate the image layer Layer -> Duplicate Layer and in the new top layer use the Threshold tool Colors -> Treshold Move the center slider a little to the left to make white areas whiter.
2. Paint out in black all of the background leaving the text.
screenshots https://i.imgur.com/vu0xF3F.jpg
3. Apply a small (values = 3) Gaussian Blur Filters -> Blur -> Gaussian Blur
4. In the layers dialogue change the mode of the top layer to Screen
5. Exporting as a new jpeg? Untick all the exif stuff. Do you need that comment? Otherwise default values give a file size much the same as the original.
screenshots https://i.imgur.com/ujAUYSo.jpg
edit: I wish I could give some simple way to improve that overall. Guessing at much of the jpeg artefacts actually come from over-sharpening. A partial reconstruction, scale the image up 400% then clean up, scale back down to original size, new borders to finish. Not a quick process. Gets this.
Try:
1. Duplicate the image layer Layer -> Duplicate Layer and in the new top layer use the Threshold tool Colors -> Treshold Move the center slider a little to the left to make white areas whiter.
2. Paint out in black all of the background leaving the text.
screenshots https://i.imgur.com/vu0xF3F.jpg
3. Apply a small (values = 3) Gaussian Blur Filters -> Blur -> Gaussian Blur
4. In the layers dialogue change the mode of the top layer to Screen
5. Exporting as a new jpeg? Untick all the exif stuff. Do you need that comment? Otherwise default values give a file size much the same as the original.
screenshots https://i.imgur.com/ujAUYSo.jpg
edit: I wish I could give some simple way to improve that overall. Guessing at much of the jpeg artefacts actually come from over-sharpening. A partial reconstruction, scale the image up 400% then clean up, scale back down to original size, new borders to finish. Not a quick process. Gets this.