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http://www.acc.umu.se/~patrikax/amiga/others/schematics/1084.zip

Get going

First of all, I have to clear up what I was looking for. I didn't want a "correct" palette, or what the developer saw, or what the developer may have intended. I just wanted a palette that exactly mimicked the NES-compatible RGB PPUs, no matter how incorrect those may have been for games compared to the NES' NTSC PPU.


So I guess this is what I was looking for. I wasn't sure if Nestopia's RGB palette was correct, though, since the browns were way too red, as you noted. But (according to you ), it is the exact palette that I'd find on the RC2C05-99 PPU or any of the Rx2C03x PPUs.

Also, you say I should set my monitor to a color temperature of 9300K. Is that because of Nestopia's implementation of the RGB palette, or is that something inherent in the RGB PPU itself?

Neither. Because we haven't yet invented perfect invincible electronics, even PC monitors vary in terms of what colors they'll display given a particular input signal. That doesn't matter for email or Clippy or even Vista Aero, but it's huge for people doing professional image work (photo or video editing). If your monitor is at a known color temperature than you can certify that RGB values X/Y/Z will match Pantone color A or whatever.

In this case, if your monitor is set and calibrated to 9300K the Nestopia RGB palette will exactly match the nominal output from the RGB PPU on an arcade RGB monitor. It's really that simple.

For NES games too? Do you have that on good authority? I find that hard to believe.

The RGB PPU. It assumes a white point near 9300K in the display monitor.

Only if the red/green/blue primaries are the same as well. And the gamma. And there are several white points commonly described as "9300K". Sorry, it's not THAT simple.

I have it on good authority from friends for the NES era, and I personally programmed several dozen commercial games on those things for 16+ bit systems. There were no decent consumer TVs under 20" with composite inputs until the mid-90s, and fitting everything in an average cubicle was an issue. The Commies were relatively cheap, reliable, and compact. And they had one final trick up their sleeves for the PS2 era: you could turn the vertical height down far enough to get real anamorphic 16:9 once that became a feature in games.

And Don Quixote here will only settle for exact RGBPPU colors for some deranged reason, so if that's the case just link the En Vogue video ("never gonna get it") and I'll lock the thread :-)

-_-

I just like screwing around with things, so I wanted to see what the games would look like with the RGB PPU!

Also, I understand that it would take quite a bit of effort to get a monitor's settings to display the exact colors that the RGB PPU is generating, if it's even possible at all for any particular monitor. That's not my real concern, though...I mean, when it comes to the emulator's color palette, I just want the emulator to generate the exact colors. As far as what my monitor does to those colors, that's an entirely different issue.

So for anyone that still wants to put up with me, what's it like for the SNES PPU, which is natively and normally RGB? I mean, is the SNES PPU also designed for a color temperature of 9300K on the monitor side, among other things?

P.S. So what's up with the color palettes that come default on other NES emulators? If none of them are the "true" RGB palette, and none of them are made to look close to the NTSC PPU, are they just random colors the emulator designers decided might look good??

For all intents and purposes natively-RGB programmable-palette PPUs like the SNES are the same as a PC video card with an NTSC encoder slapped on the back end. Of course, that wasn't literally true until the original Xbox ;-)

Aha. Because looking at the schematics and the ICs used, that monitor would have by-the-book NTSC decoding, and if you also have the Hue knob at the detent position, you'll get very greenish yellows on the NES. It's because most NES games assume color #8 is yellow. However, color #8 is not actually yellow, it's 180 degrees phase, whereas true yellow is at 165 degrees phase, so it's greener than it should be. Which is why I would assume that either most didn't use that monitor after all, or they at least turned the hue knob minus 15 degrees.

Well, now you know. It's not a pretty sight, in my opinion. Theoretically, I could take the raw RGB PPU values and convert them to display properly on an sRGB display.

I should clear things up a bit I guess.

The RGB NES PPU outputs hard-wired RGB voltages from values chosen by the chip designer. The SNES PPU outputs software-set RGB voltages from values chosen by the software developer.

RGB values are always *relative* to a color space, or color profile, defined by a monitor's red/green/blue/white primary chromaticities and gamma. The "correct" profile is whatever the designer/developer's monitor had, he chose the RGB values to look good on his monitor.

The NTSC broadcast system defines a particular color profile for North America, and different one for Japan. However, that only applies to broadcast video, there's no guarantee that a video game developer actually used a monitor of those specifications, because broadcast-quality "Grade 1" monitors are VERY expensive.

In reality, unless we ask the developer what monitor he used, it's only conjecture. However, a *rule of thumb* is that if a picture's reds and browns are too bright on sRGB with the 6500K white point, it's *probably* designed for 9300K. This certainly applies to the RGB PPU palette, as well as the old Nesticle one. On the other hand, we know that most monitors from the MS-DOS era had a 9300K white point, so most DOS games on sRGB look (slightly) wrong, not that most people notice.

While most standards, including sRGB, NTSC and PAL call for a 6500K white point, monitor makers liked and like the 9300K one because it 1) seems "brighter" to most people, and 2) it looks good even when the surrounding light comes from a fluorescent lamp. 6500K is the color of daylight and looks kind of reddish when the surrounding light comes from a fluorescent lamp.

Unfortunately, the schematics don't tell us what color chromaticities the 1084 has.

I don't think the following question was answered yet, since I'm still wondering about it, so here it is again:

Where did the YUV color palette in Nestopia come from? Who made it? How did they go about choosing which colors to use, in order to approximate an actual NES RP2C02 PPU's output (as I assume that's what this YUV color palette was designed to approximate)?