What does screen printing on vellum have to do with your portfolio cover? No one's looking for a screened cover that makes your portfolio cohesive and worth a damn. The work in the portfolio and what it accomplished is what matters.
I thought that screen printing the title of the project "Cleveland film festival" then maybe the project description under it. Then you flip the page and you see tw actual work which would be printed using a laser printer.
I thought screenprinting on the vellum would show another skill that I have, that others may not have. It's just an idea, that's why I'm
Obviously your concern is the paper buckling with the moisture of the ink. You could avoid this by using a higher mesh count to print less ink and instead of printing solid block letters you could play around with using bitmaps to get a halftone.