Page 1 of Colour question....

Why can`t I adjust the colour on my telly when watching a dvd movie? Contrast and brightness seem no problem at all to adjust. Is there a "colour default setting" or something? My player is a Pacific 1002 and my telly a fairly old Alba.

I presume your DVD is connected to your TV using a SCART lead. The video signal can be encoded two ways on the SCART - composite or RGB.

The composite video signal has the luminance (brightness information - like a black/white photo) and chrominance (colour shade information) combined into one signal. The luminance is produced by adding together the separate Red, Green and Blue signals. The chrominance is more complicated but basically comprises two colour-difference signals (Red minus Green, and Blue minus Green). Your TV combines the luma and chroma signals to re-create the separate Red, Green and Blue signals.
The colour control on your TV adjusts the balance between the luma and chroma. At one end you will have a black and white picture (no chroma) and at the other you will have an over-saturated picture (too much chroma).
This is to compensate for transmission loss (the technical term is "differential gain") or frequency response problems that can occur when a TV signal is received off-air.

If your TV is receiving RGB signals from your DVD player then the colour control will not have any effect since the RGB signal is input into the TV after the colour control and colour separation circuits. There is no need for the colour control since the signal is not received off-air - a short SCART cable cannot introduce any differential gain problems. Hopefully your TV should not introduce colour errors. Most TVs are pretty good in this respect and have been for about the last twenty years or longer since the advent of integrated circuits (silicon chips).

I imagine that the new integrated digital TVs will not have colour controls either since digital transmission is also not susceptible to colour problems.

Sorry if this seems like an overly techy explanation - it is not intended to be patronising. I hope it answers your question.

Basically, to sum up: the colour control on your telly is to compensate for transmission problems with analogue TV signals (composite video). If you dont use the analogue composite video signal (ie you have an RGB source such as a DVD) then you dont need a colour control.

Regards
Jonathan Ellis

Thanks Jonathan!
A bit more detail would have been welcome........(only joking!)
Alastair