While the hot debates of preference are confusing, we at least seem to have figured out some sort of representative ballpark of how the NTSC palette works. PAL, on the other hand, I can find very little about. I also do not own a PAL NES to test for myself, unfortunately.
I did make palette test ROMs a few years ago, which made it easy for me to take a quick video capture of a few setups I had, but I do not own a PAL system to test in the same way for comparison. All that is needed is a short video containing each of the 8 emphasis settings. Obviously a single capture setup isn't definitive, but it's at least an objectively measured point of reference.
However, even a set made by careful "by eye" comparisons of a CRT vs. the RGB on an LCD, as compromised as that might be, would be much better than the little I have been able to find.
So, here is what I've gathered. Please correct me if I get the details wrong:
The PPU has 12 hues available, in columns $1 through $C. Each step is a 30° rotation in UV chroma space, where the colourburst begins at 0° (a greenish yellow).
According to our Wiki, on NTSC the colourburst is generated by a column 8 pattern, placing that column's hue at exactly 0°. On PAL the colorburst alternates between 6 and 9 each line, giving an average of 7 + 1/2. This effectively places column 8 at 15° rather than 0°, and the rest proceed in 30° steps from there.
There's a few details I haven't reconciled with this. I've read that NTSC is YIQ and PAL is YUV, and that these two spaces are the same but 33° rotated. However, videos I can find of vectorscopes seem to be showing an NTSC colourburst on the U axis, and PAL as a pair 45° from it. This leaves me confused about where the 33° rotation of YIQ is relevant. The wikipedia article about YIQ suggests that there's an alternative decoding called R-Y and B-Y but I'm unclear about what way it's an alternative. Should the difference really be 33° - 15°, rather than just 15°?
Anyway, this leads to a theoretical set of hues, compared here against a Vectorscope diagram indicating standard angles for colours calibrated with a colour-bars picture. In this chart: blue, magenta, red, yellow, green, cyan.
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Column 1 2 3 4 5 6 7 8 9 A B C
NTSC angle 150 180 210 240 270 300 330 0 30 60 90 120
PAL angle 135 165 195 225 255 285 315 345 15 45 75 105
BMRYGC 168 240 284 347 62 104
Using Drag's NES palette generator, I generated two palettes with the default settings except for hue. I used 0 hue for NTSC, and -0.262 for PAL (-15° in radians). I believe this adequately matches the theoretical difference between NTSC and PAL which I outlined above, but I do not know if this is a good representation of the difference. Essentially the hues are just shifted by half a column.
Just below this are two palettes I derived from the only emulators I could find that so far attempt PAL NES colour emulation. FCEUX 2.6.5's PAL filter (FeosTAS) at default settings, and Nintendulator 0.985's PAL palette. I don't know to what degree either of those should be considerd representative, but they're the only thing I could find to go on.
- Drag's generator at 0° (NTSC)
- Drag's generator at 15° (PAL, theoretical)
- FCEUX 2.6.5 PAL filter
- Nintendulator 0.985 PAL palette
Also I've completely ignored discussing gamma, saturation, sRGB, etc. here. These are all relevant to generating a good representative palette, but as far as I know those factors should be equivalent between NTSC and PAL? Not sure if that's really true, but I've made that assumption because I've seen no information to suggest they should really be treated differently in that respect, at least.