I have a Draper Access V. It is a vinyl based screen and the masking / borders are just as you indicated... some sort of black paint / vinyl dye and yes when the image is spread over the border (using an X1), you can clearly see it. In fact, I sometimes watch my 4:3 TV image on my 16:9 screen with the image clearly spread over the border and screen... it is very watchable. I don't think any other screen manufacturers are any different especially in rollups. On fixed screen, I think you will find the situation a bit more improved as some have a anodized or satin black finish which has better light absorption.