Wiki-The Starling equation is an equation that illustrates the role of hydrostatic and oncotic forces (the so-called Starling forces) in the movement of fluid across capillary membranes.

 

So is it water that moves out or do solutes dissolved in water move out as well. Simply is it water or fluid(including solutes) that move out.

Both water and solutes. Water and dissolved solutes can pass through 'leaky' junctions between endothelial cells. Capillaries also have fenstrations (holes) which allow bigger solutes to pass across, anything from 10nm to 100nm.