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I would like to hear from anyone who has tried both screens with a Sony 10HT.


I have a 10HT in a 16:9 120" diagonal configuration. I have read about the virtues of both screens.


I like a bright image and have been running my 10HT with Cinema Black-Off on a white painted wall in a dark room. Interlaced DVD's and Direct TV look really good to me on the wall.


I understand the GrayHawk will produce better blacks and contrast at the cost of a dimmer image where the Studiotek will be brighter with lesser blacks and contrast. I also understand the GreyHawk was developed for digital projectors. Being able to get decent images from Direct TV via S-video is also important to me.


Should I consider the Stewart Ultramatte 150?


I would appreciate comments based on experience.


Thank you.


[This message has been edited by Tom M (edited 09-26-2001).]
 

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Tom,


Do you know whether the paint on your wall is a matte finish (not gloss)? Do you see a hotspot (shiny spot or circle in the centre of the image that moves when you move your head)? If you don't you should get an image the is similar in brightness when you use a Greyhawk. The Greyhawk is meant to be very similar in brightness to a matte white painted wall. If you are happy with your current image, you should be happier with a Greyhawk because it will give you better black and contrast.


I would not recommend a Studiotek 130 over a Greyhawk in this situation because you should have ample brightness for a Greyhawk. Similarly, you probably don't need the extra gain of the 150. I have seen a 10HT on a Studiotek 130, but I don't recall seeing it on a Greyhawk. I have seen projectors with similar contrast and brightness on a 1/2 and 1/2 Greyhawk/Studiotek 130 and I prefer the Greyhawk.


Of course, the best way is to see for yourself. You can get a sample of both for a projection test and decide which looks better to you. Keep in mind that the whites may look dimmer when compared to the Studiotek 130, but on a full Greyhawk screen you will not perceive the whites to be dim or grey, however the better black level will still be there.


Regards,


Kam Fung
 

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Have you tried the CC filter? It will produce much better blacks and you can maintain a bright screen and color accuracy by boosting and adjusting the gains. I have a homemade approx. 116-11 inch screen and find it to be completely bright enough with cinema black on.
 

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I certainly agree that a CC filter will do far more for black levels and contrast than a gray screen. Once you have the filter in place, and things tweaked up, you can decide whether you want to give up image brightness to improve black levels further by using a gray screen. Most people think not, although the decision will depend on both personal preference and screen size.


I would also stay away from screens with any gain as they can cause hot spotting, and one really does not need the additional brightness and grayer black levels that come with gain. A Matte screen seems about right to me for the 10HT when tweaked with a CC filter.


Steve



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Steve Smallcombe
 

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I got the 10HT with Grayhawk 100" 16:9.


It makes a lot of difference from the other "business" screens I have tried.


The picture does become more movie like (proff : my girlfriend complained before the grayhawk..) - better blacks - but on the downside in my oppinion there is more ambient reflection.


But if you can run with Cinema Black mode off today - then you can do that with the grayhawk as well. (about half my room is windows..)



best


Kasper


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Denon AV1SE

Panasonic 42"Plasma

Pioneer 737 DVD

Stewart 16:9 100" Grayhawk

Sony 10HT (temporary)
 

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A CC filter is a Color Correcting filter typically used by photographers. The ones used to tweak the 10HT are pink CC filters such as a CC30R. These filters typically absorb about half of green and blue light and pass most all of the red.


The CC filter tweak is based the fact that the bulb used for the 10HT has a low red output compared to green and blue, and as a consequence color balance is obtained in the factory calibration by driving the green and blue LCD panels with half their potential gain. This means that the contrast ratio of the 10HT is about half of what it could be if the green panel was be driven at full gain. Green is critical in this respect as the eye is most sensitive to green in the perception of luminescence. At the lowest light levels, the maximum sensitivity shifts further from red and more towards blue.


When you add a CC filter in front of the lens of a 10HT you cut the green and blue light levels at IRE 0 (black) in half, very significantly improving the measured and perceived black levels. In order to restore color balance one raises the green and blue gains thus increasing the contrast ratio significantly. The overall effect, compared to the factory calibration, is that one essentially keeps full brightness and color balance at IRE 100 (white) while improving the black level and contrast ratios by roughly a factor of 2. Since the eye is non linear, and is more sensitive to changes in black levels than white levels, the overall perceived improvement is perhaps even greater. If you want to learn more about how to do this using a measurement technique to get the color balance right, visit my web-site at http://home.pacbell.net/steve367


Once you have obtained the full contrast ratio from the 10HT, you can then decide whether you want to give up any image brightness to get additional improvements in black level by using a gray screen. I used to be a strong proponent of gray screens and Neutral Density filters, but the CC filter tweak is much better, and may eliminate the need for gray screens in some cases. I think a matte screen with gain of 1 is about right for a 10HT with the CC filter tweak, but that decision depends on many other factors including screen size, ambient light and personal preferences.


Steve



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Steve Smallcombe
 

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Removed the double posting.


Steve



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Steve Smallcombe


[This message has been edited by Steve Smallcombe (edited 09-28-2001).]
 

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I've recently been using Steve's process to implement a CC30R filter on my 10HT. It has resulted in a 43% increase in my measured contrast ratio. The picture is SUBSTANTIALLY improved with much better black levels and contrast. I have a 106" GrayHawk screen. Use of the CC30R filter has not affected perceived image brightness, and I'm getting the benefit of even better black levels that the GrayHawk provides. I still have some headroom left in my blue and green gains, so I'm also going to try a CC40R filter. I can't recommend this tweak for the 10HT highly enough! It's really fairly easy to do, and every 10HT owner who hasn't visited Steve's site and looked into this owes it to themselves to do it NOW :)


Tom
 

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Cool! I don't have a 10HT, but that certainly is interesting. I guess this also applies to most projectors that use a high-efficiency bulb (with less red) if they have a gain adjustment. It would seem that you would need something like Colorfacts to get the correct colour temperature after adding the filter.


BTW, ND filters only cut your light with no other benefits (contrast ratio, etc remain the same), whereas grey screens will increase dynamic contrast (measureable as ANSI contrast) because they absorb light reflected back from the room. There is, of course, a brightness penalty though.


Regards,


Kam Fung
 

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The CC filter tweak will work for any projector where the green (and blue) LCD panels are not pushed to their max. I absolutely agree that one should use a measurement-based technique to not only get the color balance right, but also to assure accurate gamma tracking as well, especially at the highest IRE levels.


As one starts to push things, a projector will often run out of one color, typically red, as one approaches IRE 100. This can cause color shifts and loss of details in the highlight area of the image. Likewise at the black end of things, it is important to assure that all three colors are set so that they reach their black point at exactly the same brightness value.


For all of the above reasons, I developed SMART or Simple Measurement And Ratio Tracking, to allow HT enthusiasts a quantitative, non-subjective way of tweaking their projectors. SMART is a low cost, DIY approach, compared to others I have seen, and has been widely used by the SONY10HT community for about 6 months now. I have Sanyo PLV 60 version in Beta test.


In the first versions of SMART, I simply put up the various gamma tracking and color balance charts and the user needed to figure out what to change and by how much. The newer versions understand the 10 HT and PLV 60 service mode parameters and give specific advice on what to adjust and by how much. It also advised what CC filter is needed to achieve color balance with all of the gains maximized.


There is no reason why SMART shouldn't work for other projectors as well; it's just until I work with someone on a projector, the advice SMART gives may not be appropriate, although the various charts will be.


Steve



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Steve Smallcombe
 
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