Tweak the C64-style palette?

[DragWx]

Is it too late in the game to ask for an improved C64-style palette for colors 0-15? One that looks more like a VIC-II, I mean.

More specifically, the (later) VIC-II generates its colors using only 9 different luminance levels, and aside from black and white, each luminance level is shared by two of the remaining 14 colors:

{black}, {blue, brown}, {dark grey, red}, {purple, orange}, {medium gray, light blue}, {light red, green}, {light gray, cyan}, {yellow, light green}, {white}.

If you want, I can try to throw something together, but I don't have the means to try it out on hardware or on a CRT.

[ahenry3068]

I have both hardware and a CRT. I even have a good tool to do the tweaks.

I don't think the default's are going to be changed but bvload "mycustom.pal",8,1,$FA00 can always go in the Autoboot file.

My palette editor.
viewtopic.php?p=30608#p30608

There's already a C64.PAL file in the archive there. Desertfish thought it was closer to the original C64 I got those numbers from him.

If you save "DPAL.BIN" (be careful doing that) then the Palette you save there will remain when the Palette editor exits.

20231125_163642.jpg (2.55 MiB) Viewed 7935 times

[DragWx]

Oh hey, that's a pretty good palette in the archive, we could probably just go with that and call it a day. Still, here's my initial attempt at generating two palettes, which I've placed alongside it.

c64_palette.png (5.02 KiB) Viewed 7918 times

"Reference" is the palette from the archive.
"sRGB" is my palette, generated from YIQ into the sRGB space, so this is pretty much what the colors would look like if you hooked composite up to a modern LCD.
"FCC D65" is my palette, generated from YIQ into the colorspace described by the original FCC NTSC specification but with D65 as the white point. This tends to look closer to how old TVs displayed colors, and indeed, my 90s-era TV tends to boost the reds like this, at least with NES palettes.

And then both of my palettes are rounded to get 4-bit values for the VERA:

Code: Select all

sRGB -    0000 FF0F 2208 BC05 2909 A303 2B02 C40D 4009 3005 550C 4404 7707 E808 6E06 9909
FCC D65 - 0000 FF0F 220B BC02 390B A301 2B01 C30D 400B 3007 550F 4404 7707 E805 6F05 9909

For a more technical explanation, I made an NES palette generator a while back. I borrowed the measurements from Pepto's Colodore project, plugged them into my palette generator to make it create a C64 palette instead, and used similar settings to what I use for NES palettes.

Really I'm just doing this for fun, but I'm curious how close or how off I am.

[ahenry3068]

I'll throw it up on my Dell VGA later. Not sure how good a Samsung phone video will be to show you on the tube but I'll see what happens with that .