Why is hue/saturation greyed out?

[caligula]

Hello, I am trying to colorize an old vintage photograph from the 1920's. I am wondering why the hue/saturation layers adjustment is greyed out? (The icon next to the mask icon at the bottom of layers palette in CS3.) Is this normal? Thanks.

[NEMESIS]

Check the Color Mode of the document. For example at Grayscale Hue/Saturation won't work...

[caligula]

Thanks, Nemesis. As you suspected the image was in greyscale and after I changed it to RGB the hue saturation adjustment was available.