clouds

SoD,
A question on the nature of clouds and albedo. Does all water vapor reflect SW or does there need to be an aggregate size with a boundary to give refection? The reason is that clouds may be a misnomer for water vapor in general. That is that the albedo effect may be directly correlated with the amount of water molecules in the air. Hence there would be a cloud effect even when there are no clouds. What could be more important is just the humidity level itself which I presume is workable out by the satellites.
I presume this has been investigated but would value your input.