Maybe on this view color would be a subjective mental entity, as Rodrigo suggests. But, then, there is a problem of what it is that we perceive. It seems that if you make color into a subjective entity, the seeming perception of an independent world of objects collapses. One thing that suggests that color and pain are not both qualities perceived to be inhering in something is that we have a notion of a surface appearing to have a color that it doesn't really have, of color illusions. That is, if you shine a yellow light on the wall, you'd say the wall isn't really yellow.
Nothing is really yellow in that situation.
But if you have a pain in an arm that was amputated, you still have the pain. So, if the pain is just as real, as far as we are concerned, whether the arm exists or not, this suggests that pain is not attributed as a quality to the arm. For if it were, it would follow the pain wouldn't exist in the phantom limb case. I haven't read the Putnam piece, tho, so maybe these comments are off-course.