Colour correction/ness

[flame]

Hey

 

I am seeing a pretty strong difference in colours between emulators, especially Javatari and Stella. Does anyone know specifically why this is and if there is a preferred source for actual colour values ?

 

This is a comparison with both NTSC, I am aware that there is a major difference with PAL.

 

I was basing my colours on this page http://www.qotile.net/minidig/docs/tia_color.html

[flame]

Here are some comparison images from Legacy of the Beast.

OpenEMU seems to use Stella core yet seems wildly different from Stella's standard. The stream from last night also used Stella but has a closer palette to OpenEMU or Javatari

 

this is maddening to me.

[+splendidnut]

Well, you do know that the colors will vary from console to console and from TV to TV right?  NTSC = Never The Same Color

[+splendidnut]

Also looks like you have timing issues (or something more elusive) going on with the numbers in the upper left.

[flame]

1 minute ago, splendidnut said:

Well, you do know that the colors will vary from console to console and from TV to TV right?  NTSC = Never The Same Color

but between emulators, and this different ?

Just now, splendidnut said:

Also looks like you have timing issues (or something more elusive) going on with the numbers in the upper left.

there's a colour cycle happening there, that's intentional.

[+splendidnut]

27 minutes ago, pvmpkin said:

but between emulators, and this different ?

Yes... because they rely on different palettes.   Stella has multiple palettes to choose from.  So far I haven't see any emulator palettes that exactly capture what I've seen on my TVs.  Stella has come close to matching my LCD TV, but not my CRT TV (understandable as CRTs have that nice glow that no one has captured yet).

 

(This is all based on my experiences with NTSC consoles)

The Atari 2600 color generation is a bit loose, users are able to tune their consoles for colors to their liking.  $1x is almost always yellow, but relies mainly upon a TVs tint control setting.  $Fx is dependent on what the user has set the color delay control (in the console itself) to, which usually ranges from a greenish yellow to a brownish-orange color.  Brightnesses can vary a bit also, but not as much.

 

Looking at the palette in the link you posted, it looks wrong to me... I've never seen $4x as a nice red with having $Fx as brown.  Usually $4x being red involves $Fx being green, and if $Fx is brown, then $4x is more of a magenta color.  Usually I end up using $3x for my reds.

 

If you are a perfectionist in colors, take a deep breath, you're in for a ride

[RevEng]

3 hours ago, splendidnut said:

(This is all based on my experiences with NTSC consoles)

The Atari 2600 color generation is a bit loose, users are able to tune their consoles for colors to their liking.  $1x is almost always yellow, but relies mainly upon a TVs tint control setting.  $Fx is dependent on what the user has set the color delay control (in the console itself) to, which usually ranges from a greenish yellow to a brownish-orange color.  Brightnesses can vary a bit also, but not as much.

Try using $Fx somewhere, and watch the console start cold and warm-up. $Fx and nearby values will shift through the color space a bit. How much they shift varies from console to console.

[tokumaru]

The problem with consoles like the 2600 or the NES is that their colors aren't internally defined in RGB, and that their video chips output composite video signals directly. The problem with this is that there's no definitive correct way to decode colors from a composite signal, specially when they're slightly out of spec, as was common in these old consoles.

 

With each TV decoding the colors differently, everyone has a different notion of what colors appear correct to them, so emulator authors have to make the tough call of selecting a specific color conversion formula or selecting a manually created palette so they can display the graphics in RGB.

 

Later consoles such as the Master System, the Genesis and the SNES had their palettes internally defined in RGB, so even though the colors also got mangled as the video signal was encoded into composite and decoded by different TVs, emulators can simply rely on the original RGB values as the intended colors and use those.