Hi, I received a Da-Lite screen and I just want to make sure that I have received the right type. I ordered a High Power, but there are several other kinds with high reflectivity offered in the model class that I bought (model B.)
Also there appears to be a small dent in the center of it, just over the handle. the anchor tube at the bottom of the screen is not dented, only the center of the main housing. should i be concerned by this or will things probably be okay?
Thank you.
EDIT: The only marking on the projector casing itself is, "DA LITE." The tiny little one-sheet "manual" that came with it only mentions that the screen is "model B" - nothing else about it, not even the size.
Joined: 08 Apr 2006 Posts: 7096 Location: Fort Collins, CO
Link Posted: Wed Jul 22, 2009 3:54 am Post subject:
High Power works fundamentally differently from all other Da-Lite screens, so it should be easy to tell.
High Power is a "retro-reflective" screen, meaning it reflects light back to the source -- like a stop sign.
The other screens are all "angular-reflective" screens of varying gains. These screens basically reflect light like a mirror, though obviously they scatter the light a lot more than a mirror.
Here's how you tell if you have a HP: hang it up on the wall. Turn off the lights and position yourself on one side of the screen, say at about the right edge or even further to the right. Now, shine a flashlight at the center of the screen and notice how bright it is. Have someone hold the flashlight over at the *left* side of the screen and shine it at the center. Which is brightest? If it's brightest when you hold the flashlight (so your eyes are close to the light source), that's a retro-reflective screen so it's a HP. If it's brightest when the flashlight is over on the other side, it's an angular-reflective screen of some type.
If it's an HP, you'll probably be able to tell a significant difference in brightness just by shining the flashlight on the center of the screen (while still standing off to one side), and moving it from "right next to your eyes" to "holding it at arms length," always shining it at the same spot on the screen. If it's brightest when the light is near your eyes, it's an HP.
For this reason -- the image is brightest when the light source is near your eyes -- HP doesn't work real well for ceiling-mounted projectors. The image will look FABULOUS when you're standing up, but sit down and it loses all its pop. If your projector's lenses are near your eyes, then the HP can work real well.
Joined: 08 Apr 2006 Posts: 7096 Location: Fort Collins, CO
Link Posted: Thu Jul 23, 2009 11:10 pm Post subject:
At least an HP is a good match for a pulldown. Waves are very visible on angular-reflective screens -- just like turning a mirror bounces the light somewhere else, waves in the screen bounce some of the light away from your eyes and you can see the waves by the variations in brightness. But the angle doesn't matter much for an HP, just like you can shine your headlights on a stop sign from almost any angle. It all bounces back to the light source. So the waves shouldn't be very visible.
Joined: 28 Aug 2006 Posts: 1682 Location: Northern Virginia
Link Posted: Thu Jul 23, 2009 11:14 pm Post subject:
atotaldoofus wrote:
EDIT:
Nevermind, I got it working right, it's obviously HP
the only problem now is that the screen is all wobbly/wavy, being a pulldown
You'll never ever see the waves in operation. Think about the theory - you have a material that will reflect light back at the source *no matter* what angle it comes from. To a degree you could tilt the entire screen up/down/left/right and you would not see a difference because the light would be reflected back in the same manner, always directed back towards the source which did not change position.
Theory aside, I used a HP for years and the theory was proven true
Joined: 08 Mar 2006 Posts: 5080 Location: Colorado
Link Posted: Wed Aug 05, 2009 7:33 pm Post subject:
garyfritz wrote:
HP doesn't work real well for ceiling-mounted projectors. The image will look FABULOUS when you're standing up, but sit down and it loses all its pop. If your projector's lenses are near your eyes, then the HP can work real well.
Gary I know you've studied this a lot but I've actually seen an HP screen with ceiling mounted Marquee and it didn't lose all of it's pop when your seated. AAMOF I remember it getting only a little brighter when I stood up. I've got a friend in firestone with an HP and he's been begging me to come and tweak his 8500 in. Let me know if you'de like to see one in action.
BTW, I just installed my Draper Onyx M1300 screen last weekend. Slight improvement over Goo painted DIY in terms of light output but OMG the Colors are so much better. I really like it but in overall perfromance it's not the equal to the HP I saw. Still, it's a beautiful screen and it's paid for so it is staying. _________________ MARQUEE HD MODS: Bring your Marquee CRT projector (or clone) back up to spec and offer even greater performance!
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I'll give the experiment a try tonight.
