This is enough to fit small size .txt file
Support. To be more precise, I believe the ctype should occupy 33 bits; this allows 1 buffer bit, which is necessary since a ctype of 0 means no signal. Furthermore, the new 4 bits of ctype should occupy "infared" colours on the spectrum - the infared spectra are absorbed at lower temperatures, and reflected at higher ones (over a spectrum of, say, 0 to 80 degrees Celsius). (This both ensures compatibility and adds a cool new feature.)
...That's because I need one more as a buffer bit.
Alternately: Allow a ctype of 0 to exist. It behaves just like other wavelengths, and carries SPRK like normal. Its colour would be 0x202020. Furthermore, to preserve compatibility, two new FILT modes would be needed: zero filter and nonzero filter. The former blocks all BRAY/PHOT with wavelengths other than 0, and the latter blocks only zero wavelengths.