I read your other Thread. Seems that if your "just wanting a DIY screen", your gonna get the "Boot" onto this forum. Now had you also been asking for other HT Building advice as well....perhaps you might have garnered a better response. No matter. Here you are. Most everyone on DIY Screens is in the midst of building, or has built their own Theaters anyway, and few offer up any bias against the sharing of HT construction details "not related" to the actual building of screens. True DIY'er share and share alike.....everything.
Lemme lay it out for you.
I'd suggest an inexpensive "Pull Down" or Electric screen. Your Acer PJ is a veritable Atomic Light Cannon. (2960 lumens @ Econ
) For such a Blazer, it still manages to sport a dynamic Contrast of 2500:1, but after it's calibrated and on Low Lamp that amounts to approx. 500:1 So your "without a doubt" best choice will be a
dark Gray surface, and judicious use of the PJ's Contrast & Gamma controls to maintain White levels and retain Color vibrancy. But you'll have an easier job than most because of your Uber-Lumens.
Your room and PJ throw location (20' from lens to screen) requires a screen size that is at minimum 120" diagonal in 16:9 (59" x 105") or 132" diagonal in 4:3 mode (79" x 105") The latter would show 10" "Format bars" at the Top & Bottom of the image, but OMG...... what a visual presentation a 6' 4:3 image provides. Could a DIY "16:9" masking system be in your future?
The budget versions og Mfg Screens that offer "Dark High Contrast Gray" surfaces are certainly affordable, even in larger sizes, and most likely there is one that is sized rightly for your purpose. Those sizes will run about $280-375.00 in a Electric version, and I'll put it as gently as I can.....anything else (manual) would be silly given the Screen must mount above the top edge of the Window's Trim.
If you desire to provide a better reflective surface than such "Gray" screens offer, (...ie: a Gain of 1.0 or more...) then of course there are DIY options on what to use to coat such screens, and instructions on here as to how best to apply said coatings. The difference would be that you would instead order up a "matte White" Screen and apply the DIY Paint of choice. Matte White Screens are almost always cheaper anyway by about 20%.
And by your opting to recoat the surface of any such matte White screen, that is where the DIY aspect saves the day as far as your getting help from those who care.
Now if your industrious enough, and willing to put some real DIY'ism effort out, you could construct a reasonably lightweight screen out of Framing/Tubing and stretched Black Out Cloth that also would have a special Gray paint applied. Such a Screen could be taken down, or moved aside.
Drywall?
At your needed size, any DIY Screen made out of a sturdy Frame and a solid material for the screen's surface would weigh in a far more a load than you'd want to manipulate.
Nope. It's either a "DIY ramped up" Mfg. Screen that can easily disappear at a touch, or a lightweight Fabric Screen that you can move without fear of becoming a Model for Mens' Truss Support Wear.
PM me if you'd like some specific suggestions as to which "el cheapo Mfg Screens" might be to your liking, and if you do not wish to further your search for a usable (...as in "affordable"...) Mfg Screen via the "Screens" Forum. Hereabouts we are committed to low cost options if possible, and you can be sure (...and advised...) that my suggestions will be firmly rooted in that mandate.
But if you decide not to paint the damn thing.....