I have been doing fluorescence microscopy on microfluidic devices fabricated in SU-8. I have found that SU-8 fluoresces in the blue-green range. More green than blue. This has not been problematic for the fluorescences of the dyes I am using are much brighter at relatively low concentrations of dye. (43 uM aqeous flourescein) There seemns to be no fluorescence in the red wavelengths.