This page is a mirror of Tepples' nesdev forum mirror (URL TBD).
Last updated on Oct-18-2019 Download

Why is determining the correct palette so difficult

Why is determining the correct palette so difficult
by on (#58588)
Every NES emulator has its own color palette. I heard that it's because there are no definite colors somehow. That's why I have a suggestion: What about the colors that the NES games for the Game Boy Advance (that "NES Classic Series") use? Shouldn't they be the basis for the NES palette? I mean, the Game Boy Advance does have definite detectable color values. And the NES games are 1:1 conversions. So, their colors should be the real deal, shouldn't it?

by on (#58589)
Nintendo did the same thing everyone else did though. They came up with RGB values they liked and went with them. They aren't official though.

by on (#58590)
Are you writing color-blindness testing software for the NES? Or maybe something that could help someone get the correct paint at Lowes? Other than an application like that, I don't see what the value would be in finding "the exact" colors the NES creates. And besides, all the NES is doing is saying: "TV, please excite your red dots THIS much, your green dots THIS much, and your blue dots THIS much." It doesn't actually have any real colors stored (what would that even mean?) *edit*. Even if you could find the exact RGB values, the NES hardware governs how strong the resulting RGB signals (*edit* I have no idea how those signals actually work, just that they somehow communicate RGB information in one way or another) really are...so as far as I understand it (and I don't know much about hardware) the best you can do is some kind of an approximation (if you're writing an emulator or anything else that needs to replicate the NES' palette) unless you were to literally physically clone the NES hardware.

*edit* I wrote a custom graphics editor for developing NES games, and I used the rgb values depicted in NESDoc.pdf. For all I know, those are the correct values. Worked fine for my purposes!

by on (#58592)
What's so hard is that the original NES does not process RGB signals. Instead, it generates a video signal directly in the composite domain to be decoded into RGB by the TV's NTSC decoder. This causes a bit of a problem, as a lot of TVs don't decode NTSC according to spec; some models put more blue into the signal to make it look better on the showroom floor, and some models (especially those for the Japanese market) warp the decoding to try to make flesh tones look better-than-real.

A couple relatively rare Famicom versions (e.g. Famicom Titler and the one built into a TV) generate RGB signals directly, as do PlayChoice 10 arcade boards. Some of the colors in these palettes are so off that developers of some NES games rereleased in arcades had to change a few colors here and there.

MottZilla wrote:
Nintendo did the same thing everyone else did though. They came up with RGB values they liked and went with them. They aren't official though.

Moreover, the palette in the acNES emulator, used by e-Reader, Animal Crossing, and Classic NES Series, is gamma-corrected for the GBA's comparatively dark screen, not the more-or-less-sRGB display of a TV + GameCube + Game Boy Player accessory or a DS Lite. The palette in Virtual Console for Wii is probably closer to Nintendo's intent.

by on (#58595)
When in doubt, use the BMF 30 palette.
Re: Why is determining the correct palette so difficult
by on (#58596)
JohnJohn wrote:
Every NES emulator has its own color palette. I heard that it's because there are no definite colors somehow. That's why I have a suggestion: What about the colors that the NES games for the Game Boy Advance (that "NES Classic Series") use?

Using a color palette designed for a portable system with a possibly non-backlit LCD with different gamma depending on the hardware revision doesn't seem like a good idea.

by on (#58606)
Isn't the NTSC color simulation in Nestopia supposed to be pretty accurate? If so, just load one of the several PD ROMs that show all 52(?) colors on-screen at once, tweak the simulated TV knobs to your liking, take a screenshot, then extract each color one-by-one and place them into a new .PAL file. Load into your favorite emulator and enjoy. That's what I did, anyway.

by on (#58614)
Image

Is this one as good as any? It's what I've been using.

by on (#58623)
The main question of the thread is based on what I think is a false assumption - that Nintendo has any additional info about the NES that we don't have. I've checked before and there were always quite a few visits to this site from obvious Nintendo domains.

But I've been surprised before, one thing that comes to mind is the music engine in Star Tropics 2 doing funny stuff with the $4011 register.

by on (#58626)
I think the PPU is an open-and-shut case. We've captured the waveform and know it's a matter of how the TV decodes it, which differs across models. $4011 involved some at the time unknown behavior (non-linear output curve).

by on (#58628)
Memblers wrote:
false assumption - that Nintendo has any additional info about the NES that we don't have. I've checked before and there were always quite a few visits to this site from obvious Nintendo domains.

Unless they came to make sure we're not spreading "teh romz".