I want to increase the color depth for my user account in kde. I cannot edit the configuration in /etc/X11. Is it possible?
No, it is not possible to change this outside of the xorg.conf configuration. You can look here:
If the variables are available for run-time configuration they will say:
"and the value can be changed at run−time with xset(1) ..."
You can see the Depth settings don't have run-time configurations:
specifies which color depth the server should use by default. The −depth command line option can be used to override this. If neither is specified, the default depth is driver−specific, but in most cases is 8.
specifies which framebuffer layout to use by default. The −fbbpp command line option can be used to override this. In most cases the driver will chose the best default value for this. The only case where there is even a choice in this value is for depth 24, where some hardware supports both a packed 24 bit framebuffer layout and a sparse 32 bit framebuffer layout.
I've looked into this and although what I found didn't solve my problem, it answered my question. The simple solution is to build a xorg.conf file
Xorg :1 -configure
this produces an xorg.conf.new file. You can then modify it adding
Section "Screen" ... DefaultDepth 24 ... EndSection
Then you place that file in
/etc/X11/ or similar
This worked in so far as it made the color depth 24 but it seems my issue was an incorrect driver or something of that sort.