Hello all.
I'm trying to implement a palette generator so that I can do a better job on the colorimetry of converting from a mid-90s television's gamut/color correction behavior/EOTF/etc. to sRGB.
I've run into a few places where I'm unclear on what the behavior of the NES is. Help would be greatly appreciated!
I'm trying to implement a palette generator so that I can do a better job on the colorimetry of converting from a mid-90s television's gamut/color correction behavior/EOTF/etc. to sRGB.
I've run into a few places where I'm unclear on what the behavior of the NES is. Help would be greatly appreciated!
- Both Drag's generator and palgen-persune have a knob for setting a phase offset on hues 0x2, 0x6, and 0xA, but default to 0 with no documentation for what a sane value is. Searching this forum, I found this discussion, and also a continuation here that sounds like it nails the root cause. Eyeballing this image, it looks to me like the offset is about +4.5degrees, maybe a bit more. Does that sound right? Is there more discussion/explanation of this somewhere? In particular, any discussion about what the numerical value of the offset is?
- palgen-persune has a knob for setting a luma boost on hues 0x4, 0x8, and 0xC, but again defaults to 0 with no documentation for what a sane value is. I have failed to turn up any reference for this at all. Why do these hues get a luma boost, and what's a realistic value for it?
- Both Drag's generator and palgen-persune have a knob for setting a phase offset that increases with the luma step. Drag documents this as about -2.5 degrees per luma step for the 2C02E chip, or -5 degrees per luma step for the 2C02G. Searching this forum turns up this original discussion, and this, and this, and finally this. Is -2.5 (or -5) degrees per luma step still considered correct?
Statistics: Posted by ChthonVII — Mon Oct 28, 2024 8:11 pm — Replies 0 — Views 44
