New High Contrast High Power Discussion Thread - Page 9

I would, though, caution persons to check out the HCHP with samples from Dalite to verify that its very narrow viewing cone doesn't lead to brightness variation from their viewing position. Even though I have basically just one viewing position, since I sit rather close (1.0 SW) to a large screen, my RS20 has to be ~ 4-5 ft behind my head (so that I can do the zoom method for 2.35, going to a 144"W pic).

In my case, the samples of HCHP showed brightness fall off at the left and right edges of the screen; maybe not noticeable on viewing real material, but it was definitely noticeable with a white screen. The HP2.4, though, was perfectly uniform in brightness (due to its somewhat wider viewing cone). Also, since I have black absorbing material on the ceiling and side walls (out ~8ft from the screen wall), I am not concerned with the more side wall reflected light the HP2.4 might have over the HCHP.

One might think it does in theory, but IRL it doesn't.

You get an improved contrast ratio due to the image being brighter, but that's about it. The screen is not darker than a normal 1.0 gain white screen when exposed to light from the sides (well the HCHP is ever so slightly darker due to its light grey substrate). However comparing a HP or HCHP in side light to a FireHawk and we're talking night and day differences.

I will take some shots and post when I get back from work.

BR

I disagree.

The 2.8 gain white drops to around .6 or .5 gain at large angles. If you have a light colored room and get secondary reflections then it will complicate things, but the 2.8 gain High Power does have lower gain for the first reflection from side light at a big angle than a true 1.0 gain screen to a center viewer. The high gain for on-axis light doesn't magically appear, it comes with lower gain than 1.0 gain for certain angles.

Of course it depends on your definition of "ever so slightly" but I would say that the HCHP has much lower gain for side light from a big angle than a true 1.0 gain screen. I could measure it probably this weekend, but I don't think there is any way it is even .5 gain (it would be lower than that for a viewer in the center).

I could see that with certain angles where the Firehawk hotspots so much that it is a viewer on the opposite side from the side light and at the same angle who gets most of that gain. If the side light was a little to the side instead of way to the side then the Firehawk can actually show pretty high gain for that light to a viewer sitting in the center and looking at that side of the screen. This is if the angle works out with high gain to that spot on the screen with the angular-reflective Firehawk. This is a case where I would expect the HCHP to have less of an issue.

In the past I measured ANSI CR retention in my setup with off-white walls and the Optoma Graywolf (retro-reflective and gray for 1.4 gain rating) resulted in higher ANSI CR measurements for a viewer in a high gain position compared to my Firehawk in the same room. I expect that the HCHP would do about as well as the Graywolf or even better for this test in the same room, but I haven't measured it yet.

I'm not sure that I have the numbers perfectly right, but I recall that the Graywolf resulted in something like 140:1 ANSI CR to a center position in this off-white colored room, where I would expect a basic matte white would end up at less than 50:1 ANSI CR based on other measurements. This was I believe using a projector that put out over 500:1 ANSI CR.

--Darin

glad i asked the question and prompted a discussion...

for reference, a couple pics of the room... the windows and door have blackout curtains, they aren't shown, i took these while i was painting...

darinp2

After examining it again: Looking at light only coming from the side I think you're right with the HCHP at least. It is significantly darker than white screens and the Firehawk is very dependent on the seating position. However, the 2.4 and 2.8 HP don't fare as well.

This is the setup: A diffuse light is shining from the side at the screen.
Attachment 230754

The screen is the HCHP

Samples from left to right:
FireHawk G3
HP2.4
HP2.8
Studiotek 130
Da-lite Matte white gain 1.0
Firehawk.

The pics are taken from different sides of the couch:
Attachment 230751
Attachment 230752

As you say, the Firehawk samples have very different brightness, which of course is due to their angular reflective nature. However, the HP2.4 and 2.8 samples are only slightly darker than the white screens.

ok, my samples of both the hp and hphc arrived today...

played around with them for awhile... big difference from the bd (plus my 3d issue doesn't exist, yay!)...

both of my seats will be within the 20 degree viewing cone for the hphc (measuring from the sides of the couch gives a potential 15 degree "maximum", assuming i remember my high school geometry right ) once i lower the projector to the correct level...

any real advantage at that point to going with the "regular" over the hc?

i'm leaning towards the hc... blacks defintely wash out less with ambient with it...

thanks again for all the commentary...

fwiw...

i ordered the hphc from mike at avs today...

reports to come...

I've started to notice some issues with my HCHP screen and was wondering if any other owners were experiencing what I am. On bright scenes the image is not uniformly bright. There are slightly darker spots all over the screen. I have already had the screen replaced once due to this and the replacement had the same issue. You can see what I am referring to in the pics of a 100 percent white window being shown. It is almost as if the screen is dirty. Other than this issue I love the screen but I am worried my third screen (second replacement) will have the same issue. I am thinking of going with the regular high power instead. I sent the pics to da-lite and they said to have the screen replaced again. My non-scientific guess is that the reflective surface is not uniform across the screen and the darker spots are where the gray back is showing through.

I noticed brightness falloff of the HCHP when testing samples I received from Dalite (put up at the corners of my intended screen), which I attributed to the much narrower viewing cone compared to the std HP2.4 (which did not show this falloff). For this reason I got the std HP.

Now this may be because I sit rather close to a large screen (11 ft from a 12 ft wide one), so the pj has to be ~ 5-6 ft behind my head. The relevant viewing angle (between the 2 lines from pj and eye to a point on the screen) thus varies at various points on the screen more so than if the pj were close up behind my head. So I decided that I needed the std HP which works better for my situation.

I haven't noticed any difference in uniformity specifically at the corners. I sit 17' back, projector is 19' back and 1' above my head, so that might have something to do with it. The darker spots are across the entire screen, middle and sides. I saw from a previous post that you have a dedicated theater room with black curtains on the walls beside the screen as well as the wall behind your seating. I too have this setup. Black velvet curtains 4' out of each side of the screen,. black rug 5' out from the screen and the entire back wall is covered in black curtains. My walls and ceiling are also dark gray.

My biggest reason for going with the HCHP was it being a gray screen and it helping with the perceived black levels. I have a sample of the regular HP which I tested out a little bit last night. I didn't notice much difference in a 0 - 20 ire test pattern between the HCHP and the regular sample. Now one thing I did notice about the HCHP compared to my matte white screen is that it was very good at limiting reflections from the screen to the walls, which might be the contributing factor to the improved black levels. Maybe the regular HP with its slightly larger viewing cone will still possess these properties? I love the HCHP screen, but am worried about getting another with the same problem. I'm also wondering if the regular HP will provide just as good an image in my setup.

I imagine that the std HP will have more reflections from side walls, but as you noted, I have absorbing side wall and ceiling coverings, so for me that is not an issue.

I think both the std HP and HCDP 2.4's are excellent screens. I even like mine better than my earlier HP2.8--which I also liked very much--in that I think the new HP gives a smoother image.

So I take it you do not experience the issues I am on bright images on your regular hp? Is a 100 percent white window completely white?

Yes, very uniform brightness.

Can any of you suggest me here what to do in this situation ? I am planing to buy the Epson 6500UB refurb unit and I was looking around for screens, then found one which is known as Optoma Panoview 106" Fixed Frame Graywolf II Projector Screen, the description says VELVET FIXED FRAME SCREEN, GRAYWOLF II GRAY GLASS BEADED SCREEN and 1.8 GAIN. Do you guys think this a good screen ? I have no idea what I might be getting here ? My room is ok for light as I mostly watch in night time only. Any suggestions will be appreciated. Thanks

You should create a new thread in the main Screen forum and ask. This thread is all about the Da-Lite High Contrast High Power screen.

Few questions about this screen:
Where is can you but this?
How much does it cost for it in a manual pull down and fixed frame?
How would this do in a room that has light gray ceilings and yellow walls? Would it make the room to bright?
Im using an epson 8350 with about a 13 foot throw image about 100 inches.

^^^

you can call one of the avs guys... i've bought a lot of stuff from mike (his number is 585-671-2968)... they have competitive pricing and awesome customer service...

he can also advise you as to what it is going to do in terms of lighting up your room... i would hazard a guess that given the limited viewing cone, it will light up your room far less than a "normal" screen...

just as a fwiw... i was pretty amazed at the difference (not with this screen, but with another light rejecting type screen) how much of an improvement i got when i painted my white walls grey... and then even more of a difference when i made the whole front of the room black...

a quick update...

mine came yesterday (kudos to mike, 5 days from order to delivery, with 2 of them being over the weekend)... 110" 16x9...

pieced it together in about an hour... the little tool they include to help pull the snaps into place came in REAL handy for getting the last of the snaps attached... stuck it up on the wall... i'd describe installation as "relatively simple", i did it myself in about an hour, with assistance from swmbo to hang it on the bracket... some of the screws on the corners were "fun" to get in correctly, and screwing the bottom brackets to the frame was impossible by hand (for me, anyway), but went in easily with an impact driver (carefully used)... note to self: ensure screen is centered on wall BEFORE screwing bottom brackets to wall... excitement got the better of me and i forgot this part... was an easy enough fix though...

i have not yet moved my pj down to "optimal" height (hopefully that will happen later today), so it is still about 30" too high... i was too lazy to do that yesterday... plus i wanted to play with it...

ran an autocal... all numbers good there, with the exception of a very large blue oversaturation at 75% that i need to figure out... that's for another thread though... one note on that though, the radiance/chromapure autocal/d3 combination may be the coolest "geek toy" i've ever owned... and being a lifetime geek, that's saying something...

initial impressions...

- this thing is BRIGHT... looking at the numbers after dialing in 6500k at 100% ire, twice as bright as the bd 1.4 it replaced... it will be interesting to see what i get when i move the pj down and get black curtains upon the back wall... pretty darn good picture with track lights "full on" in back of room...

- very little screen structure noticeable... only on very bright scenes does it show itself, and even then, it's minimal... if it hadn't been something i was specifically looking for and trying to produce, it's likely i wouldn't have noticed it upon initial viewing... swmbo (who, fwiw, isn't the "normal wife", she's pickier than i when it comes to a/v, my waf is the opposite of most ) REALLY liked this... literally 15 seconds after sitting down, the first words out of her mouth were "the sparklies are gone"... big win for me there...

- fired up espn 3d to watch the football game... worked very well... besides the brightness difference (which allowed me to reduce the shutter timing and almost eliminate the ghosting), it's nice to be able to move my head around without causing the interactions i was getting from the bd... sat there and watched the whole game... i know many think 3d is a gimmick (and it must be admitted, i used to feel that way too), but dang, it is COOL!

more to come later after i move pj and spend some time with it (and get past the "my new toy is so cool" new owner stage ), but color me very happy with this choice... thanks to all who posted input...

now all i gotta do is sell the bd and i'll be REAL happy...

does anyone own the new epson 5010 and a high power screen?

Well, I ended up going with a regular HP screen (non high contrast) as my replacement to the two HCHP screens I had uniformity issues with, dark patches on bright images.

This regular HP has a similar issue except it is no where near as noticeable as the HCHP. The regular HP appears brighter and blacks appear to be the same between the two screens. I guess my dedicated theater room has something to do with it.

Since I saw the issue on 3 different screens and it appears on both the HP and HCHP screen, I am guessing the darker areas of the screen on bright images are where the reflective beads are not as thick and I am seeing the white or gray of the screen itself. Hopefully no other HCHP owners experience the issues I did.

This issue sounds so familiar with one I had a few years back with my Da-Lite HCCV screen.
I still own an HCCV screen, but shortly after I installed it, I started noticing vertical streaks during bright scenes, like when the camera panned across the sky, or a bright snowy scene.
Ultimately Da-Lite replaced the screen. They said there was an issue with the coating.
Now it sounds like another model is having the same sort of issues.

Just currious... how do you figure your dedicated room is the issue. Do you have total light control from outside light?

I'll attest to that...
AVS took care of me when Da-Lite wouldn't.

Yes my room is 100% light controlled with dark walls and ceiling as well as black velvet curtains beside the screen and at the back of the room. Since it is 100% light controlled I am betting this is why I do not see a percieved difference in black levels between the HCHP and HP screen.

That would be correct. The HC and any non white screen is meant to help in none light controlled rooms. By reducing the color of the screen to a light gray you help blacks when there is some light illuminating the screen from a source other than the projector. Remember Black is just the screen color with no light shining on it.. so a white screen in a completely dark room is the same color as a gray screen in a completely dark room.. add some light from reflections or other source and the gray screen will look darker than the white..

I'm questioning that... unless the light from non-projected sources is brighter in spots across the screen. If so, then until he addresses the ambient light issue, he might as well experiment with painting his wall and save himself some money because he's dealing with an issue that can never be totally corrected until the ambient light is addressed.

Not sure which post your are referring to, I was responding to the post above mine..
This one
http://www.avsforum.com/avs-vb/showt...0#post21491780

And just stating the way a non white (gray screen) help to increase perceived contrast by being a darker color to start... the poster I was responding to has a light contorted room and could not see any contrast improvement with the HCHP.. which would be expected..

Not sure if you are referring to my post but ambient light is not an issue in my setup. No windows, dark walls and ceiling, and dark velvet fabric on parts of my walls.

Maybe part of the reason is that ambient light is a somewhat ambiguous term.

I believe that most take it as meaning a light source other than the pj, whereas some include light from the screen reflecting from room surfaces and back to the screen.