Hi Steven, thanks for info.
I just did a new test with a CMYK pattern instead (printing all single C M Y K colors separately). Paper set to Epson Premium Glossy.
I printed a dense test pattern on Jetstar Premium material from Mega. Ink: Epson Claria.
I found that C M Y were not neas as resistant to UV light as K.
K (black) was definitively the best (black).
Exposure 60 secs in a tube UV exposer (semi professional type).
I have attached an image of the result when developing. 
