List of the Old Skool palettes

[ptoing]

I just used Promotions Gray function in the palette box, which seems to do the trick. There are several ways to convert things to grayscale, so yeh, Promotions does it right in this case.

[Mathias]

Ai, what are you talking about!? Hehe, crappola. I had no idea simple greyscale conversion could be so complicated. The terms "ycbcr" and "rgbp" don't appear once in Photoshop CSIII's help docs or any other Adobe CSIII's help docs for that matter. I'll look into this more, later. I'll have to see what other imaging tools I can get t deal with pixel art projects more accurately.

But, can we at least define the actual colors for the C64 pal in easy to use hex codes?
When importing a palette into a working image document it's easy to accidentally ruin it with different color space conversions, which may sometimes impose very subtle dithering when converting, thereby increasing the amount of colors in your sprite or scene unnecessarily. Having defined hex to refer to would prevent that, here's my submission, can we all agree on this? :

[Helm]

It's not a matter of agreeing on one, every c64 differs a little on its actual color ramp because of some technical reasons.

[Mathias]

Didn't know that, how odd.
But does every C64 not target the same colors, despite the actual output differing?
How much difference are we talking about?

The #7 post in this thread by ptoing does contains an image with an alternate C64 palette with much more saturation, called VIC20, but I don't know where/when it occurs.

[saimo]

Ai, what are you talking about!? Hehe, crappola. I had no idea simple greyscale conversion could be so complicated. The terms "ycbcr" and "rgbp" don't appear once in Photoshop CSIII's help docs or any other Adobe CSIII's help docs for that matter. I look into this more, later. I just don't have the tools I guess.

Do not be scared, it's easier than it seems.
To obtain the grayscale value of an RGB value just use this simple formula: (R * 0.299) + (G * 0.587) + (B * 0.114).

F.ex.:

 orange: RGB #FF8000

 ->

 R = 0xFF = 255
 G = 0x80 = 128
 B = 0x00 = 0

 ->

 (255 * 0.299) + (128 * 0.587) + (0 * 0.114)

 ->

 76.245 + 75.136 + 0

 ->

 151.381

By rounding 151.381 you obtain the value of the RGB components of gray color that corresponds to the initial RGB color:

 R = 151 = 0x97
 G = 151 = 0x97
 B = 151 = 0x97

 ->

 gray: RGB #979797


saimo

[Ai]

Didn't know that, how odd.
But does every C64 not target the same colors, despite the actual output differing?
How much difference are we talking about?

I don't know all the reasons. I do know that YPbPr is a relative colorspace, and its meaning is dependent eg on the contrast setting of the display device. YCbCr is it's digital equivalent.

BTW, I later found out that GIMP supports decomposing an image to YCbCr (with various variants) -- see the menu item Colors->Components->Decompose and choose one of the YCbCr variants ending with '256'

Also, rgbp is a pixlab internal term, sorry. It just means standard gamma-adjusted sRGB, the colorspace practically everything uses.

The #7 post in this thread by ptoing does contains an image with an alternate C64 palette with much more saturation, called VIC20, but I don't know where/when it occurs.

On VIC20 computers, naturally.
http://en.wikipedia.org/wiki/VIC20

Saimo, thanks for showing a bit more presence of mind than me Yeah, the input actually doesn't need to be normalized (at least for calculating the Y channel) and you do only need to apply the first row of the matrix to get the desired data.

[ptoing]

One reason the colours on each C64 slightly vary is because they use resistors for the colourinformation, and those resistors are each slightly different because Commodore was being a bit cheap here.

Also, that image that Mathias posted up there wants me to go all OCD over the official names of the colours, but I wont *bites fist*

[Helm]

I think Mathias shares your ocd-ness so why not give him the actual 'official' color names ?

[Gil]

I find the C64 palette absolutely lacking in the darker shades. Is anyone agreeing here? You can't do a subtle dark scene with these colors...

[ptoing]

Official names are on this page.

http://www.pepto.de/projects/colorvic/

Gil: how about this?


Also, try and compare the C64 palette to any other limited colour fixed palette of the olden days. It may not be perfect, but it is by far the best.