Converting color photos to RGB images

[Harini Nagendra]

Hi everybody,

I have a query I am hoping someone can help with. I have a series of old
color photographs of an area which I need to scan and study to see how it
has changed. Is there any algorthm to convert a composite color photograph
into individual RGB intensities? Is there a unique way of doing so? Or
even a heuristic which may have some (hopefully estimatable) degree of
error in back-converting? How do people usually deal with this?

Thanks,

Harini Nagendra