The theme has low contrast and is abstract in order to be boring on the long term or agressive for the user's eyes.
Done with the Gimp.
No other source image than the Debian logo.
The original picture has been done in 1920x1080 in order to be resized more easily. For the same reason, the main colors of the theme can be changed easily if a blue version is wanted (or other main colors). The main color is only on one layer).
As GRUB, SysLinux, ... need a low definition (colors between from 4 to 24bits), the picture has a simpler design for these cases. It need only two colors (800*600 because it's a Grub requirement):
If it's possible to change the text color I would prefer to have the grub output in black so the swirl could be in grey like the main wallpaper.
Source: the xcf file (10MB)
Author: Stéphane Blondon