HIGH POWER a Review! Part 1 - Page 121

Well I had approx 1/5 of the top of my screen darker. Not lines, the entire screen area. It could be especially seen on a white projected image. I first noticed it watching hockey. Taking a flash photograph clearly showed it as well.

I initially thought it was the screen damaged maybe by the rollers as mine is a manual pulldown. Another poster suggested cleaning it.

After a careful cleaning the dark area was completely gone.

I have just received my brand new high power screen but it does seem to me what I have received is not high power even though on the box it says so!

The screen I have received has jut a plastic fabric painted with a glossy white paint. There is nothing on the fabric other than the paint. This is different from the older 2.8 version I used to have a couple of years ago. It had that tiny particles glued into the fabric. It did have a rather rough and coarse surface. My Panoview Graywolf II screen material also has that coarse surface. These must be the glass beads glued to the surface. The new High Power screen I have received doesn't have that surface. Moreover, it does not have the bright punchy image I remember from memory my previous high power used to have.

I am wondering if this is about the new 2.4 version or, is it possible they have mistakenly put another type of screen in the box? This is not matte white I think. Maybe this is a video spectra screen?

Any idea where the problem could be?

Thanks in advance.

Take a flash picture of the screen next to a white wall and it will be very obvious. The high power fabric will look like it's glowing in comparison.

Also, the high power screens come with a little tool to help stretch the fabric onto the snap studs because the fabric is a lot less stretchy than other fabrics and it's very difficult to snap the screen on without using the tool.

--
Steve

Flash picture is one of the best ways to tell. You can hang a piece of printer paper on the screen and the flash should make the screen light up and paper look much darker. This photo and description can help identify the HP 2.4 but was originally to figure out if you got 2.4 or the now discontinued 2.8.
http://96.227.248.64:999/dalitehp/photos/Texture.html

Hello,
This is the manual pull down version. I guess it is not supposed to have the little tool you mention.

Thanks, Ramin

So I understand the new one is quite different though from the sixth picture I could still infer they are essentially of the same texture though the new version has finer beads, right?
The one I have got does not seem having any beads on it. It looks like just a painted screen fabric.

Sounds like someone screwed up, time to call the people you purchased it from.

Steve,you can put a light behind you and walk close to the axis of that and see the increase in gain as your eyes get close. There should be an immediate increase in gain.

The original 2.8 is smooth to the touch as well as the 2.4. There are big particle glass screens that are not washable and rough to the touch, but the 7 micron sized 2.8 gain was a completlely different animal and washable. You must have been mistaken here.

Regards
David

Regards
David

New material has sort of a grid pattern to it. Old is smooth.

Right, I forgot there are other types of screens Plus it would still be possible they included the right tool but the wrong screen fabric.

Here are some pictures I took when Da-lite sent me samples. The first one shows what they look like with light coming from the side, and the second one was taken with a flash, showing the magic of the high power fabric.

http://www.datamagic.com/da-lite/off-angle.jpg

http://www.datamagic.com/da-lite/on-angle.jpg

How did you clean it?

The official cleaning process can be found on the Dalite website.

I used a clean, white microfiber cloth that I dampened with the distilled water. I then lightly rubbed the screen going in one direction from the top - down. I did this process in "rows" all the way across the screen surface.

I then let it dry for about 2 hours and repeated this process twice more focusing more on the darkened area.

After that the screen looked brand new. The dark area was completely gone.

The main thing to remember is you want to cloth damp enough to clean but not soaked so water is dripping off it. Also don't use a lot of force when wiping.

Good luck.

Quick question...

I have read that the High Power material is about the best to get for a manual screen, as apparently it doesn't warp over time like other materials... it apparently keeps its shape better. Is this true?

Warp? You mean waves? It does often have waves but they are usually not visible. There are more important things to consider when selecting a High Power. For example, will it work in your setup? The geometry is pretty restrictive, eliminating many fixed offset DLP's from consideration, for example.

Yes and no.
There are 2 ways a screen wrinkles.. well probably more...
But for this discussion lets stick with 2.
First the screen material will stretch, the HP does not stretch so we are good there.
Second the roller will sag , the bigger the screen the longer the roller and the likely it is to sag.

In this case, the HP is better than most, the waves are not as likely to be seen when viewing content do to the nature of the micro beads. Under certain lighting you will see them but a lot less than other types of screens.

I am also not sure how well this holds true with the current HP2.4 since the fabric is not exactly the same as the 2.8.

Then the other type of wave is where they don't put the fabric on the roller straight to start with and it shows up with wave..

I have a couple of samples from dalite, and even with the projector mounted about 6'6"(sony HW30ES), the samples are brighter than my current 1.4 gain black diamond screen when seated. Also, i like the retroreflective screen, as i'd imagine it would have less light scatter than a regular angular reflective screen.

Well there you go! You've done the homework. Sorry, it just sounded like the warping was your primary concern.

BTW, airscapes response is a good one.

so the pulldown High power screens do get waves? how noticeable would they be? i'm getting a fairly big screen, around 125" 16x9.

You won't see the wrinkles or waves since it will reflect the light back to the source. What you'll see is the slight distortion due to the wave.

Example: Open up a book. Put your hands on either side of the page and push inward making a "hump" in the middle of the page. See how the words look? That's what a panning shot on the screen will reveal. How bad it is simply depends on how bad the wave it.

Great review!
[img]http://www.************/jie1.jpg[/img]
[img]http://www.************/jie2.jpg[/img]
[img]http://www.************/jie3.jpg[/img]

It took a few days but I finally read through the entire thread. It was epic, filled with fantastic stories of cones of light, betrayal, a cat speaker, and fly poop!

I was most interested to hear what people thought about black levels, as that was a concern of mine. I'm now satisfied that I won't have anything to worry about. While technically the black level is raised, it's not a problem in the big picture. Here's my understanding:

Let's say you have a projector which measures:
white: 10 fL
black: 1 fL

This projector has a dismal contrast ratio of 10:1.

Now on a 2.0 gain screen, it measures:
white: 20 fL
black: 2 fL

Is this correct? (I think some people, when they hear high gain screens raises both blacks and whites equally think that would mean 20 fL white to 10 fL black, which would certainly mean a washed out image.)

This preserves the contrast ratio of 10:1, but the perceived contrast (actual contrast?) has greatly expanded. While the black level has raised, it is now 18 fL dimmer than white, rather than just 9. In a high contrast image, the 2.0 gain screen actually shows more contrast (though the ratio is the same), and the black would probably appear blacker.

How does that sound?

So screen 4 looks good to summarize, top portion across the screen developed a darker horizontal area. Some suggested cleaning, I opted on warranty replacement and the new screen material was delivered on the roller in a crate. Had to swap the motor in, deal with some minor creases, which I am sure will work itself out, otherwise this looks good so far. I pressed for an answer on what I could expect being different here, and this is what I was told:

Airion >>> That is my exact understanding as well and keep in mind the human vision sensitivity to brightness; When displaying a full black image onscreen from a projector with poor contrast ratio the "black" will look more like dark grey but displaying an image with areas of black and white suddenly that "black" looks a lot more like you expect it to look because of your vision acquiring areas of white highligts at the same time, which "fools" your vision into seeing a darker "black".
You can do your own test at home by using a test dvd/blu-ray disc displaying a full black pattern followed by an ANSI pattern, which consists of 16 squares of adjacent black/white patterns.

this is mostly true. Although there are some of us that can't be "fooled". I can see bad blacks period. It doesn't matter if it's a solid black screen, or a mix of bright and dark, if there are bad blacks - I can see it regardless. This is why I was never happy with the Epson 8350 - a bright PJ with bad blacks.

I'm not sure if "fooled" is the right word. It's my understanding that the human eye, given the human iris, can only see a limited range of contrast at a single time. This is why CRTs look good despite low ANSI contrast due to reflections in the glass. If there is an image with very bright whites and even poor blacks, your eyes adjust to the whites, letting in less light. The whites are dimmed to a comfortable level and the blacks are dimmed to pure black in your eyes.

Perhaps the Epson 8350 suffered from poor ANSI contrast, elevating the blacks in a bright image? Was this a problem with the projector or a problem only when viewing it on a high gain screen?

Any users of Da-Lite high power 2.8 gain screen can sharing some snapshots to show its performance under ambient light?

Unfortunately there wouldn't be much point. The 2.8 fabric has been discontinued for a while now and the 2.4 replacement is manufactured differently. I can tell you from first hand experience that 2.8 was better in this area. The main reason was it is brighter in the sweet spot. Even with the 2.8, if I leave the viewing cone, the image quality will be that of a matte white screen with or without light hiting the screen.

Sorry if this info is in here somewhere - is there a "best way" to DIY a fixed screen using HP material from my 92" model C? Looking to do an 80" wide 2.35:1.

Thanks!

Do anyone know the lowest gain of this screen can be when you move out of the viewing cone? I'm using a 2.4 HP

See the graph in the attachment which shows the gain vs angle for the old 2.8 and new 2.4 HiPower. It shows that the gain of the 2.4 has fallen to ~ 1.5 by 15 deg off axis, and to ~ 1.0 at 45 deg.

 

Da-lite Hi Power New or Old what did you get.pdf 305.41015625k . file