Entering the dark mode on the C64

Dark theme for applications and operating systems is one of the most requested features over the past time. Both Apple and Google made a dark theme an essential part of user interface/UI. Dark theme reduces luminance and provides safety in dark environments, typically suitable the retro man cave. Interestingly enough the color scheme was already very popular in the 60’s as the monochrome display was flashing its characters in green or amber.

The first monitor which i got for my C64 was a monochrome green CRT (i think it was a Thomson VM3101G\Commodore 1201) and the green glow of the display has made a massive burn-in impression on my heart.

Not much later my C64 and 1541 got upgraded by installing DolphinDOS 2.0. The DolphinDOS kernel (or as Robert Russell misspelling: kernal) sported the ‘green on black’ color scheme.

The memory area where the kernal resides is $E000 – $FFFF. This ROM needs to be dumped or downloaded as a file prior to the modification. Altering the kernal isn’t much of a deal if you know how to handle a hex editor, such as HxD by Maël Hörz. Just load the kernal file and change the following values at the correct offset while using the hex editor.

Now you can use the new kernal either by configuring it in your favourite emulator/FPGA board or for the real hardware fanatics; burn the image in an (E)EPROM.

ColorOffsetDefault value
Characters$0535#$0E█████
Border$0CD9#$0E█████
Background$0CDA#$06█████

As a reference the color scheme from C64-wiki.com

ColorHex valueAppearance
Black#$00█████
White#$01█████
Red#$02█████
Cyan#$03█████
Violet / purple#$04█████
Green#$05█████
Blue#$06█████
Yellow#$07█████
Orange#$08█████
Brown#$09█████
Light red#$0A█████
Dark grey / Grey 1#$0B█████
Grey / Grey 2#$0C█████
Light green#$0D█████
Light blue#$0E█████
Light grey\ Grey 3#$0F█████
C64 color scheme by https://www.c64-wiki.com/wiki/Color

This entry was posted in C-64, Hardware and tagged , , , , . Bookmark the permalink.

Leave a Reply