RGB Values for PAL and NTSC Colours

[snicklin]

Hi all,

 

Where can I get a list of the R, G and B values for all 128 / 256 colours for the Atari.

 

I'd like to use them to write a tool in my Go/Golang tool chain.

 

Thank you!

[matosimi]

There are several palettes available.

I have been using laoo.act taken from g2f or atari800winpl.

The act file is a binary of 128*3 bytes of I'm not mistaken... So it is fairly easy to use.

 

There are more advanced palette options in altirra, many profiles and sliders... I'm pretty sure there is a way to save/export the palette, but i cannot tell you the format exactly because I'm typing this message on a phone.

Edited February 27, 2022 by matosimi
Typo

[snicklin]

9 minutes ago, matosimi said:

There are several palettes available.

I have been using laoo.act taken from g2f or atari800winpl.

The act file is a binary of 128*3 bytes of I'm not mistaken... So it is fairly easy to use.

 

There are more advanced palette options in altirra, many profiles and sliders... I'm pretty sure there is a way to save/export the palette, but i cannot tell you the format exactly because I'm typing this message on a phone.

Thank you for this, I will take a look.

 

I need to ask a question which has puzzled me for a long time. Why is there more than one palette? Surely the colours that an Atari produces is are fixed RGB values for each colour? (Forgetting that PAL is different from NTSC). Why are different palettes interpreting these differently?

 

For example, the darkest black on an Atari must be fixed at 0,0,0 surely? Why would one palette maybe make it 0,0,0 and another would make it potentially 1,1,1? 

 

Perhaps the RGB values are different peoples interpretations? Is that the answer? But if they were analysed scientifically, they'd only be one set of R, G and B values surely? Or do different Atari models have slightly different colours?

[+Stephen]

1 hour ago, snicklin said:

Thank you for this, I will take a look.

 

I need to ask a question which has puzzled me for a long time. Why is there more than one palette? Surely the colours that an Atari produces is are fixed RGB values for each colour? (Forgetting that PAL is different from NTSC). Why are different palettes interpreting these differently?

 

For example, the darkest black on an Atari must be fixed at 0,0,0 surely? Why would one palette maybe make it 0,0,0 and another would make it potentially 1,1,1? 

 

Perhaps the RGB values are different peoples interpretations? Is that the answer? But if they were analysed scientifically, they'd only be one set of R, G and B values surely? Or do different Atari models have slightly different colours?

Unfortunately, it is not.  The colour circuitry in these machines is purely analog in nature (a resistor ladder DAC of sorts).  Varying voltages and phase shifts determine how far "around" the colour wheel to deviate.  It's not like a modern graphics card that literally uses fixed RGB values for what it produces.

[snicklin]

15 minutes ago, Stephen said:

Unfortunately, it is not.  The colour circuitry in these machines is purely analog in nature (a resistor ladder DAC of sorts).  Varying voltages and phase shifts determine how far "around" the colour wheel to deviate.  It's not like a modern graphics card that literally uses fixed RGB values for what it produces.

Aah I see! OK, quite a simple answer at the end of it. Thank you Stephen.

 

I am thinking then that the best values to use are an averaging of the different palettes, providing all palettes are known to be reasonable representations of the colour output. Or is there a palette already conceived that is known to be an averaging of the other palettes?

 

Interesting subject, I am loving this conversation.

[Rybags]

Not really fixed values at all - 2 different machines of the same model or among the different models, you get different results.

Then you have TV vs monitor and the interpretation there, not to mention NTSC vs PAL.

 

I reckon just pick something you like and run with that.

[matosimi]

For instance Fandal is using default.act on his website, it is a default palette of Atari800WinPlus emulator, which is quite oversaturated and too vivid...but he started to build his archive by creating screenshots using that palette and still doing it same way these days:

this is same screen with altirra default palette, which is my favorite one:

laoo.act palette was used by g2f (no idea if that is still true) and it is more accurate... i am also using this palette in atari fontmaker and atari mapmaker:

also there is real.act palette, which is (I guess) made by photographing the atari TV screen and extracting colors from the photo, the main visible difference is that $00 black color is greyish:

...

These are PAL versions, NTSC palettes are different. Commonly known is that black-white gradient stays at its place (colors $00-$0f).. and rest of colors are shifted by $10 (so the HUE is shifted by 1) ...this technique is used in couple modern games that are explicitly stated as NTSC compatible. Also NTSC does not have red color but multiple orange-brownish ones.

 

In order to make a game PAL/NTSC compatible with respect to palettes it requires using indexed color palette in the code instead of constants in order to switch between PAL/NTSC color scheme... so it complicates the code and slows it down. It is possible to replace all the constants between PAL/NTSC (by self altering code) but that requires list of addresses of each color register change in the code... to be honest I did not do that yet in any of my projects so far (I'm always focusing on 50/60Hz timing recalculation and removal of glitches caused due to missing offscreen VBI time on NTSC).

Edited February 28, 2022 by matosimi

[ClausB]

Even the same machine's pallet can vary with the potentiometer setting. There is disagreement over how to set it properly. Should hue 15 match hue 1, go beyond it, or fall short?

[Thelen]

I've used these RGB values for the colors in my Mode4 tool. Off course their probably not perfect, but had to use something ?

First row=color 0, last is 15. the eight colums are hue's 0-14 in Hex values RGB.

PALcolors.txt NTSCcolors.txt

[EddyFree]

On Sunday, February 27, 2022 at 4:14 PM, snicklin said:

Where can I get a list of the R, G and B values for all 128 / 256 colours for the Atari.

Dim Shared RGBTable(1 To 768) As UByte => _
  {0,0,0,0,0,0,29,29,29,29,29,29,59,59,59,59,59,59,89,89,89,89,89,89,119,119,119,_
  119,119,119,149,149,149,149,149,149,179,179,179,179,179,179,209,209,209,209,_
  209,209,48,20,0,48,20,0,77,49,0,77,49,0,107,79,0,107,79,0,137,109,21,137,109,_
  21,167,139,51,167,139,51,197,169,81,197,169,81,227,199,111,227,199,111,225,229,_
  141,225,229,141,65,0,0,65,0,0,94,18,0,94,18,0,124,48,5,124,48,5,154,78,35,154,_
  78,35,184,108,65,184,108,65,214,138,95,214,138,95,244,168,125,244,168,125,255,_
  198,155,255,198,155,69,0,0,69,0,0,98,0,0,98,0,0,128,19,30,128,19,30,158,49,60,_
  158,49,60,188,79,90,188,79,90,218,109,120,218,109,120,248,139,150,248,139,150,_
  255,169,180,255,169,180,60,0,1,60,0,1,89,0,30,89,0,30,119,0,60,119,0,60,149,28,_
  90,149,28,90,179,58,120,179,58,120,209,88,150,209,88,150,239,118,180,239,118,_
  180,255,148,210,255,148,210,38,0,31,38,0,31,67,0,60,67,0,60,97,0,90,97,0,90,127,_
  20,120,127,20,120,157,50,150,157,50,150,187,80,180,187,80,180,217,110,210,217,_
  110,210,247,140,240,247,140,240,9,0,55,9,0,55,38,0,84,38,0,84,68,0,114,68,0,_
  114,98,25,144,98,25,144,128,55,174,128,55,174,158,85,204,158,85,204,188,115,_
  234,188,115,234,218,145,255,218,145,255,0,0,68,0,0,68,8,0,97,8,0,97,38,12,127,_
  38,12,127,68,42,157,68,42,157,98,72,187,98,72,187,128,102,217,128,102,217,158,_
  132,247,158,132,247,188,162,255,188,162,255,0,0,68,0,0,68,0,9,97,0,9,97,11,39,_
  127,11,39,127,41,69,157,41,69,157,71,99,187,71,99,187,101,129,217,101,129,217,_
  131,159,247,131,159,247,161,189,255,161,189,255,0,11,54,0,11,54,0,40,83,0,40,_
  83,0,70,113,0,70,113,24,100,143,24,100,143,54,130,173,54,130,173,84,160,203,84,_
  160,203,114,190,233,114,190,233,144,220,255,144,220,255,0,40,29,0,40,29,0,69,_
  58,0,69,58,0,99,88,0,99,88,20,129,118,20,129,118,50,159,148,50,159,148,80,189,_
  178,80,189,178,110,219,208,110,219,208,140,249,238,140,249,238,0,61,0,0,61,0,_
  0,90,28,0,90,28,0,120,58,0,120,58,29,150,88,29,150,88,59,180,118,59,180,118,89,_
  210,148,89,210,148,119,240,178,119,240,178,149,255,208,149,255,208,0,69,0,0,69,_
  0,0,98,0,0,98,0,21,128,28,21,128,28,51,158,58,51,158,58,81,188,88,81,188,88,111,_
  218,118,111,218,118,141,248,148,141,248,148,171,255,178,171,255,178,0,64,0,0,_
  64,0,20,93,0,20,93,0,50,123,4,50,123,4,80,153,34,80,153,34,110,183,64,110,183,_
  64,140,213,94,140,213,94,170,243,124,170,243,124,200,255,154,200,255,154,21,47,_
  0,21,47,0,50,76,0,50,76,0,80,106,0,80,106,0,110,136,21,110,136,21,140,166,51,140,_
  166,51,170,196,81,170,196,81,200,226,111,200,226,111,230,255,141,230,255,141,30,_
  14,0,30,14,0,77,49,0,77,49,0,107,79,0,107,79,0,137,109,21,137,109,21,167,139,_
  51,167,139,51,197,169,81,197,169,81,227,199,111,227,199,111,255,229,141,255,_
  229,141}

 

Not sure how accurate they are as I've never really compared them. Used them in a pic utility I wrote in 2008. Got them from an old version of Atari800win I think.