Resin Starvation?

The appearance of the panels I've been wet laying and and vacuum bagging has me a bit concerened. I'm using epoxy and 24oz triaxial 45,45,90 on 3/4" 5lb pvc foam. I believe the 90 layer is double the weight of the 45 layers and appears lighter in color after cure. I've seen this in nearly all my vacuum layups with this fabric including those in a mold and those with and without breather/bleeder. The only layup that it hasn't been apparent is one single layer without peel ply. My typical resin content is averaging around 37%, 63% fabric. I stopped using bleeder because my resin content was dropping below 35%. I've seen some commercialy availabe panels laid on PET core and the glass also has a lighter color. Is this glass apearance typical for vacuum layups?