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Discussion Starter #1
I have been Hometheater-ing for the last two years. I got started with an avsforum favorite projector of about two years ago, the Panasonic 711XU LCD PJ. The PJ has done well for me, but as of late I have become more and more dissatisfied with the greyish blacks on many darker movies and HDTV network TV shows (such as ABCs ALIAS). At the moment I didnt want to spend the money to replace the PJ, so I started looking at screen upgrade options to maximize the hardware I have.


My Setup:


HT is in my basement with good but not total blackout light control. I can turn off all lights and shade the one window, but the ceiling is white and the carpeting is a light tan. Walls are a dark brown wood paneling.


HTPC (Windows XP SP1, Radeon 9000 Catalyst 3.7 drivers, Revolution sound card)

Zoomplayer (Sonic 1.51 video and windvd 5 audio filters)


Panasonic L711XU LCD 1024x768, 1600 lums, 400:1 CR projector


Previous screen: DIY Glidden Universal Grey painted 80x45 screen. See my review and experiences with my previous screen here:

http://archive2.avsforum.com/avs-vb/...eyhawk+glidden


Research:


I fairly quickly settled on Screen Goo as my next DIY screen option. Goo Systems recently started listing distributors and dealers on their web site. One is in the USA in the metro DC area and close by. I have seen various postings on the different colors/flavors of Goo. I sent an email to KBK and he recommended Digital Grey for my setup. One of my primary objectives was to enhance black level. So I wanted to go as dark grey as I could. Also I did some calculations that confirmed for me that I have enough light output to be happy with Digital Grey:


Panny 711XU LCD PJ 1600 lumens output

Usually operated in econo mode @ 20% derating (panasonic spec sheet)

4:3 aspect ratio 1024 x 768 PJ shooting onto a 16:9 screen (1024 x 576 useable pixels) 576/768 75% output

Calibration and aging bulb 15% derating (my guess-timate)

Screen Goo Digital Gray Gain .85 (worst case from previous KBK posts)


1600 * .80 * .75 * .85 * .85 = 653 effective lumens


80 x 45 screen = (80*45) = 3600 sq in = 25 sq ft.


653 / 25 = 26 lumens / sq ft.


26 lumens/ sq ft seemed like a reasonable level and probably not to far off from my current screen setup.


Painting:


My previous screen was rolled. But I read several postings that Goo performance increases with spraying. I purchased a Wagner 1800 psi power painter sprayer from home depot. I have never sprayed before. I practiced with white primer paint on a 8 x 4 sheet of ($8.99) hardboard. It was a disaster. I was never able to get the mixture thinned and the sprayer output controls to give me a even spray. I would get so far, and then the spray would start spitting out globs of primer. I made sure that my spray reservoir was always at least half full. I decided that my painting skills were just not upto the task of spraying with the expensive goo paint. I gave up and tossed the 8x4 hardboard that was now primer glob covered and started over with a new sheet and rollers for the goo screen.


A big advantage of rolling the paint, I could mount the bare screen wood on the wall in my home theater and roll it in place. I had planned on spraying in the garage and then moving and mounting the screen afterwards. I was always worried that the screen might become damaged during the moving and mounting process. Rolling in place has its advantages.


Some tips from my rolling experience:


Goo Digital Grey basecoat is much thicker than topcoat. 1000ml of Basecoat does not cover nearly as much area as the topcoat. Basecoat is cheaper than topcoat. I recommend that you purchase one size larger jug of basecoat than topcoat. In my case, for a 80x45 screen, I needed about 900 ml of base but only about 500 ml of topcoat to complete the job.


I choose to paint the primer, wait 24 hours, paint 2 coats of basecoat, wait 24 hours and paint the 2 coats of topcoat. Lines and imperfections fade after the paint has dried a bit. I liked the idea that if I had too, I could lay down an extra layer of paint before going to the next primary/base/top layer.


I used a new roller and roller tray liner for each type of paint (primer, base, top coat). I applied the first coat of base, put the wet roller in a plastic baggie, waited an hour, and used the same roller for the second layer of base coat. Did the same with a new roller for the top coat. A lot of paint sticks to the roller, using the baggie trick can save a few ml of the expensive goo paint between coats.


Painting the screen in place in my home theater, had one other advantage. Common recommendations suggest painting with as much flood lights on as possible. I found that that was a good recommendation, but that also important was to turn off all lights and turn the projector on. My PJ projects a blue screen when no signal is applied on the inputs. The blue screen shined on the screen showed rolling issues where the flood lights did not. I recommend that you paint the first coat with the flood lights on, wait an hour, turn the PJ on, inspect the screen for issues, then turn the flood lights on and paint the second coat.


Results:


I initially was somewhat disappointed. Even with careful attention to my roller technique, I still had significant vertical banding on my screen. Noticeable difference from one roller stroke to the next. I posted some about this and you can see the pictures here:

http://archive2.avsforum.com/avs-vb/...&highlight=goo


I also, incountered some weird blue hotspots/rainbows. These were areas of the screen that seemed to reflect shiny blue in darker scenes. You can see an example photo attached. I should note that the picture attached is not representative of the performance of the screen. The camera has captured the colors completely wrong from what I see with my eyes. However the purpose of the shot was to capture the blue hot spot.


EDIT ON: as discussed later in this thread, the BLUE RAINBOWS are now thought NOT to be from GOO. Read on. EDIT OFF.


I consulted with goosystems tech support over the phone. They recommended that I wait a couple of weeks for the screen to fully cure. If that was not enough they recommended that I get extra fine sand paper, sand down the screen and put an extra layer of top coat on.


I have now waited 4 weeks and am quite a bit happier with my goo screen. The screen has curied and the hot spots and vertical banding are significantly reduced. I am trying to determine if they have faded enough or if I should sand and reapply another topcoat. The roller stroke bands are only visible on very lightly colored projected scenes and only if I really look for them. At the moment I will probably use the screen as is.


To end on a positive note, the goo screen did give me better blacks. But not only did I get noticeable better blacks (I would guess that the black projected is about 10-15% blacker than my previous screen), but also the colors seem truer as well. I also noticed a much more pronounced 3D effect that I had not seen so much before.


In conclusion, I would say that the goo screen does yield better blacks, contrast and truer colors than my previous DIY glidden universal grey screen. However, goo is harder to roll than regular house paint and much more sensative to application technique and expertise of the painter.
 

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I still can't figure out what the blue spot is.......
 

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Sure looks like a dead pixel to me. It's to bright to be a dust blob which is more visible in darker scenes.
 

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I'm assuming this happens more often than in just that scene. Does it occur on the same place on the screen everytime? With the lights on, is there a noticable difference between the places that these blue spots appear and the rest of the screen? It's very possible it could be something happening with the projector or your source, I find it hard to believe the screen would be producing such image artifacts in certain areas, but those areas not be visibly different from the rest of the screen.
 

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Discussion Starter #5
Blue spots at their worst were just visible 2 or 3 times a movie. Now that the screen has cured, I have not seen one in awhile.


Exact same PJ setup with my previous screen NEVER had blue spots.


I know what dust blobs and stuck pixels look like. This is not that.


Location of blue spots varies and seems more dependant on the scene in the movie. Blue spots happen in darker portions of the movie scene.


My best guess is that the blue spots happen when there are very dark areas and very light areas or light source (note the spotlight in the top of the 5th element screen shot) in the same scene. Somehow the spotting is occuring with some sort of weird field of view, viewing cone, mirroring effect to have the very light part of the scene reflected in the dark part of the scene. Idea#2 is that the blue spotting was caused by excess water/mosture still in the base coat in areas where I rolled to thick under the topcoat before the screen fully curied.


The blue spotting is much reduced (I have not seen it in awhile) now that the screen is curied.
 

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Discussion Starter #6
I am still trying to figure out what is going on with the blue spot or halo. They are not very frequent.


I am starting to believe that the sample I have posted is not due to my GOO screen at all.


Can someone else playback the scene I have posted and see if you have the same blue spot?


5th Element, superbit version, chapter 22, 1 hour 32 minutes 8 seconds into the movie.


I am also seeing blue halo's in Agent Cody Banks, chapter 13, 33 minutes, 3 seconds
 

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The BLUE SPOT or HALO, is a LENS EFFECT of the FILM CAMERA.


Sorry for the capital letters. I just saw it last night in the film. I hadn't watched it in a long time.


What is happening, is the screen is sooooo good..... that it is showing you that much more of the film!!!


Also, there was some independent testing of our product recently and the Digital Grey Basecoat with Digital Grey Topcoat, came out with a gain of 1.5 on axis, with very little drop in output off-axis.


So there you go. The hottest output gray screen in existence, with the best off axis response...and in a can---- for cheap.


No wonder people like it so much.
 

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Exactly that scene. It is a bit of light caught in the layers of the camera lens.


I used to see this stuff all the time with my CRT projection set up. Only now is Digital Projection finally getting close enough to even -begin- to show it properly.
 

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Wow, this Goo paint really seems the way to go.

What paint would you recommended for an X1 wanting to

project a 106cm 16:9 image????

for improved Blacks,contrast etc

Can i buy it anywhere in Australia yet??
 

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We have Australian distribution. Go to the Goo website, at www.goosystems.com for the distributor list.
 

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Same here. I rolled on the base and topcoat (white) for my CRT. I was unhappy with the finish because it had banding, slight hotspotting and colorshifting. After only 3 weeks of curing, it looks really sweet now and I bet it just gets better. I'm a happy camper. You just need a little patience with the Goo....


Cary
 

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yep. we tell people about 6 weeks to finish curing, depending on conditions, but the reality is that it takes about 6 months in normal house temps and humidity to "fully" cure.
 
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