2 replies to this topic

[cd-w]

I am attempting to convert some colour values from NTSC to PAL using the TIA Color Charts.
This is proving to be a difficult process, and so I have two questions:
1) Has anyone already produced an approximate mapping of colour values between PAL and NTSC.
2) Is there really no PAL value for pure yellow?

Thanks,
Chris

[Tom]

I've fiddled around with this once.

My approach worked somehow like this:

1) Parse the NTSC and PAL RGB values from the TIA color chart

2) Say we want to find the PAL color that is closest to NTSC color # 66: Find the RGB value for color # 66

3) Find the RGB value of the PAL color that is closest to the RGB value of NTSC color # 66. I did this by calculating the distance of the RGB color triplets in the RGB color cube: d = sqrt((rn-rp)^2 + (gn-gp)^2 + (bn-bp)^2) (rn = red component of NTSC color and so on).
The PAL RGB triplet for which d is the smallest is the closest color.

4) Find the PAL color number that corresponends with the PAL RGB triplet found in the previous step.

This kind of worked, but not perfectly.

[Andrew Davie]

cd-w, on Mon Apr 18, 2005 7:54 PM, said:

2) Is there really no PAL value for pure yellow?

What's a "yellow"?