https://www.epson.nl/viewcon/corporatesite/products/consumables/overview/paper/gprp/ccffePET film so equal to Mylar. With a coating.
SP WT7900 is mentioned as a suitable printer as it has a white ink too;
¨witte inkten op de SP WT7900, samen met UltraChrome HDR-inkten C, LC, M, LM, Y, Or, Gr,"
Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htmJuly 2016 update, 700+ inkjet media white spectral plots