I may have been the one to introduce Fidelio to the AV world some years ago. Trust me, I did all the tests and Fidelio was overall superior. Once upon a time Jo Ann carried it at $25/yd. They no longer carry it so my on-hand supply has become something of a hoarded treasure... funny to see me handle a 4-inch square scrap and wonder if I should toss it or keep it! “I could stick this somewhere...” ; - )
The thing about Fidelio is its behavior at shallow angles of incidence or grazing angle, when the light is sort of skimming off the surface like it would if it makes a right-angle junction at the screen.
The little fibers that make up the plush are key. The "shinier" more glassy synthetic fibers tend to make the better traps, as the light gets bounced deep into the material where it is more completely absorbed. But that behavior is tied directly to how those fibers lay and their end cut, which also gives a greater or lesser sheen. We of course want no sheen at all, but that's not what they make the velvet for!
Typically a true velvet has a main axis that shows its magic, one direction in which it typically shows the greatest amount of sheen, that sheen being light bounced back to the observer. The opposite direction usually is the "dead flat" orientation, with little retro-reflection (sheen). THAT is what we seek. You would align the fabric so that direction faces the light source you need to control.
Fidelio has excellent performance on that main axis. The unique thing about it is that it also has a second axis perpendicular to the main that also can be factored into your plan... not as stellar as the main axis, but it's worth considering since it's there!
Since a Hobby Lobby has opened in town, I checked out their best velvets. Certainly less expensive and even more inviting with those “40 percent off” coupons that seem to happen every week! Just giving a quick once-over in the store I could see that it was no Fidelio. I bought a yard, took it home, did a perfunctory test, called it crap and put it away. I have been fully spoiled by Fidelio! Begone, underachieving velvet!
Looking at it with a less harsh eye, it’s certainly adequate on the main axis. Heck, I dug out a really bad stretchy-velvet that I nearly threw away and found it wasn’t so bad on the main axis. I now use it on the floor in front of the screen like a scatter rug ("anti-scatter" rug??) during “serious” viewing sessions, then roll it up and stash it until next time! Why not... it’s better than the bare floor and gray rug, I don't care if it's stepped on and I have no other use for it!
Some other minor points:
Velvet is a challenge to adhesives... many tapes just don’t seem to stick to the backing fabric! I don’t use spray adhesive because as my needs change, I’d like to be able to reconfigure and reuse materials, especially expensive ones! I have discovered a really good “permanent” transfer tape at Jo Anns that just bites into the velvet and gives a great bond but still can be pulled away if needed (keep in mind that this also pulls out some plush fibers). Unfortunately, I can’t find the package... if you prefer a tape go check it out if you can figure which one it is! Typically I'll prepare a support panel out of plastic-clad foam board or insulation foam board, apply tape around the backside perimeter and a few "dots" on the front surface for added stability, then lay the fabric, pull it slightly snug around the edge, secure firmly to the tape and trim.
With many velvets, you can sweep over the surface in the "dead flat" direction (just your bare hand can work) and like steeling a good knife back to a keen edge it aligns the fibers and really improves the light-sucking power of the material.
I like aircraft. I like stealth aircraft. I like the old F-117A because it used what was available at the time and made it work. Flat facets. Simple and effective.
I have a stealth credo for light control, sort of prioritizing my approach based on ease of implementation. “Avoid what you can. Deflect what you can’t. Absorb the rest.” Here’s a few things I’ve done to give you some ideas.
If my projector had an adjustable iris (fixed-variable, not auto) to reduce output further I’d use it. But it doesn't. I do have an ND2 filter on the output lens. It’s stuck inside a lens shade I stole from a camera lens, which I in turn stuck to the proj lens assembly to kill side-scatter. Needs some velvet lining, though!
From cable box to receiver to clock, everything has some stupid BRIGHT display. It adds up to a big puddle of light in the room. I don’t need or want something with doors. When I do a cal run with my laptop, it’s got some big ol’ green status leds and a screen that can’t be dimmed to less than “supernova” (well, it’s a little too bright...) Since I don’t want to go so far as wearing a black cloak there’s a lot of bounce off me. I picked up a roll of dark window tint film at WalWort and presto! A little neatly-trimmed overlay and we have some control. Makes a nice temporary screen damper on the laptop, too. I layer it in areas that aren’t showing essential data for more dark goodness.
My room has a suspended ceiling with a 2 x 2 foot grid. I picked up some black “blackout” (as opposed to white blackout...) drapes at WalWort and using binder spring clips (those black metal “C” shapes with the two silver handles?) hung them from the grid. Though time consuming, they are easily taken down for more formal events. I could stick some hooks in the drapes and hang them via the hooks, or turn them into Roman shades if I needed a new hobby. As they are, they are snug to the ceiling and prevent light leaks from the other side. Other stuff (shelves, gear, RPTVs) is along the walls so the drapes are 2 feet out and hide all that. It creates a little shoe box cinema. The drapes are nowhere near as effective as velvet, but more on that later.
The back wall where the projector lives had black fleece or felt straight across. It wasn’t so great. Using stealth tactics, I hung it in a W shape (think of the saw tooth trailing edge on a B-2 bomber.) Now, instead of being bounced right back at the screen, light gets redirected to the side walls etc. for further absorption at each “hit.” From the screen, this looks almost as dark as an expensive velvet at a fraction of the cost. “Don’t use a nuke if a rock will do.”
In a “duh” moment, I was calculating where to cut my opening for the image passthrough... I had turned on the proj to warm up... I looked up and saw the image in “rear-projection” on the fabric. Picked up my scissors, cut away and was done with it in 15 seconds with great precision!
There are areas that cannot be fully addressed with “avoid” or “deflect.”I have “the good velvet” right up at the screen area and around the proj where it yields the best performance-per-unit for controlling scatter. The side wall drapes are candidates for getting some better localized absorption at the seating zone first-reflection points (just like setting up speakers... use a mirror to precisely locate the first bounce point for the screen. The back of the speakers (facing the screen) get attention as well as the tops which are piano-black acrylic. Pretty, but they mirror the screen, so I just lay a piece of fabric on top for the session.
Not wanting to go so far as make the entire ceiling and floor black (I do have my limits!) I use baffles and gobos.The ceiling has several baffle sheets to prevent direct paths from the screen to the white ceiling. A large semi-cylindrical baffle is hung side-to-side from the screen plane to 4 feet back. Straight-drape baffles don’t hide the ceiling from the screen at this proximity. It should be a sharp-edge V with the screen-facing surface angled to prevent bounce-back to the screen but I’ll do that later with some triangular formers cut from pink insulation foam panels.
Gobos are portable panels. I picked up some really cheap garment racks with two-piece vertical poles. Using just one section gives me a roughly 2 x 2 foot frame with built-in stand. These are draped with WBFIH (Whatever Black Fabric is Handy) and set on the floor about four feet back from the screen and angled to redirect any bounce into the V-trap formed at the intersection with the side wall. If I find scattered localized areas where I can kill some light without extraordinary effort, I can make more simple gobo panels from insulating foam board wrapped with WBFIH.
In my available space it’s really just advanced turd-polishing, but meeting the challenge is really fun in a McGuyver kind of way. “Ok, this a spoon. What else can I use it for?” “Tangental bearing surfaces?”