Colour fill in JPEG image

Hi,
I have an old photo with lots of light black in it and I'd like to change it to a dark black. Is there any way of converting/filling the light to dark, or could the background be changed to another colour ??
I know it's something simple but I cant seem to find anything in the manual about it.

Many thanks.

That is what the Image->Adjust menu is for.

Play with the options there.

Or, duplicate the image and change the blending mode to Multiply. Also check adjusting Curves.