CurtPalme.com Home Theater Forum

[J Kildare]

I have always maintained that room color and layout has more to do with contrast than a lot of the specs published with these projectors and a lot of their inflated ratings.

My room is fairly dark by most peoples standards, and I pay for it every time I have to work in it

The screen is a 124" Stewart 1.3 G3 scope, and just received my projector (RS-4810) which I plan on mounting 17-18' from said screen.

On the lower parts of my ceiling I used the flattest darkest paint I could find at the time Benjamin Moore Ulti Matt Black Iron. On the walls is GOM 701 black going out 6' past the screen. While the paint does not seem to affect colors onscreen (probably a little darker than 18% grey), you know there's a ceiling there if your looking for it, which means it will be reflecting on screen as well, affecting contrast, whereas the GOM disappears. The rest of the room, to the left in the pic is the patterned GOM which should not affect color, but again contrast rears its head.

Being as the weakest link is always the downfall of any system be it cars, projectors, or contrast is there even going to be a perceived difference in 99% of rooms going from say 50k - 120k contrast

With proper masking a given. In a black velvet room I say possibly, anything less not likely.
Comments?

Oh, and for consideration....

[HogPilot]

+1! I think most people underestimate how critical the room itself is to realizing the full potential of their system. The room is an equally essential component of any A/V system, and as with any other component it can only serve to detract from the original signal. Audio treatments and coloring/light absorption are as key to system performance as any other portion of one's system.

[J Kildare]

Thanks HogPilot, I'm just trying to wrap my head around the room vs contrast thing and at what point there are gains to be had.

I would still like to get a Lumigen and maybe a lens, so money does become an issue as well.

I have not unboxed the 4810 yet, and might consider the 56 if I thought there was a real world gain to be had, but I'm not sure my room is even dark enough to take advantage of it.

This is one area that does not seem to be discussed or measured much.

[HogPilot]

[WanMan]

[ecrabb]

[HogPilot]

[Spanky Ham]

Crabb is correct. If you want to know more than you ever wanted to know, then go read my buddy Darin's article about the subject at Secrets of HT.

Hog,
I think Darin did that to one of his rooms.

[WanMan]

The whole head to toe in black velvet was discussed many years ago and gave rise to the HT term 'bat cave'. In fact, my ski mask joke has to be many years old in that is the last factor in honky reflection.

[J Kildare]

[J Kildare]

Still researching and came across this on AVS:

The world's most perfect calibration instrument cannot measure how our brain interprets what our eyes see. Some attempts have been made to emulate how humans perceive light but science has yet to produce an instrument which tells the whole story.

SMPTE's human factors work resulted in their Recommended Practices document RP166-1995: "Critical Viewing Conditions For Evaluation Of Color Television Pictures." This is the work from which D65 bias lighting is taken. The document actually devotes much more attention to color perception than eyestrain. Here are some links that dramatically demonstrate how ambient lighting and surrounding surface colors in the room can cause us to think we see better black levels, enhanced contrast, and/or perceive distorted colors that aren't really in the image.

http://www.echalk.co.uk/amusements/O.../illusions.htm (Note particularly the "Colour perception" and "Colour perception 2" demonstrations.)

http://www.lottolab.org/articles/illusionsoflight.asp (Note particularly the "Brightness illusions" and "Colour illusions")

Professional monitor environments (where critical image analysis is conducted for mastering video programs) use tightly controlled lighting and neutral colored surfaces surrounding the display. The demonstrations above make very clear the importance of incorporating similar room conditions, if image fidelity is desired. This material also makes abundantly clear how destructive to image fidelity the Philips 'Ambilight' colored light features and similar gimmicky fads really are.

Human visual perception is seldom sufficiently understood when consumer display systems (and even many professional ones) are designed and implemented. Since our human vision is so adaptive, we can think we perceive a "natural looking" image but actually don't, if viewing environment conditions are incorrect. The demonstration material at the links above should provide considerable practical reinforcement for folks who have a hard time being persuaded by imaging science theory alone, or even the decades of proven imaging industry professional practice.

If you think there is some trick being used in the online images, try printing out the colored demonstration patterns and making your own paper masks. You will see that the only "trick" involved is being provided by your own brain. This is why even a perfectly aligned display device can indeed look different than a calibration report says. Conflicting viewing environment conditions, such as the wrong lighting or colored room surfaces within the observer's field of view, will ALWAYS distort how a video image appears to the viewer. No calibration instrument can measure this function of the brain. It's simply a perceptual issue.

If a consumer cares about achieving the same "look" of a video program in their home that the mastering technician enjoyed, calibrate the display, and emulate the viewing environment conditions professionals consider best practices. I like to think of this extra effort as fidelity insurance.

Here's a white paper discussing these issues and how they can be incorporated into designing good viewing systems: http://www.cinemaquestinc.com/ive.htm .

Best regards and beautiful pictures,
G. Alan Brown, President
CinemaQuest, Inc.
A Lion AV Consultants Affiliate

"Advancing the art and science of electronic imaging"

-----------------------------

And post 6 here:

http://www.avsforum.com/t/1436767/the-truth-about-black-levels

Jim

[HogPilot]

^ Exactly what I was talking about. Alan is an outstanding resource in the calibration forum over there, as are several other members, and quite accurately and succinctly presents why our viewing environment is just as important as the displays that we view. Those illusions blew my mind the first time I saw them - it's amazing how relative and adaptive our visual system is, and how quickly it will fool us into thinking we're looking at something that we're not!

[Spanky Ham]

http://www.hometheaterhifi.com/technical-articles-and-editorials/technical-articles-and-editorials/understanding-contrast-ratios-in-video-display-devices.html

[HogPilot]

I guess my original (and subsequent) response to the room issue was more global in nature and not focused on CR, which was the OP's original thrust before he started talking about white point and color perception. Darin's article above is a fantastic discussion on system CR, and I remember reading it back when he first wrote it. In terms of On/Off, the only scenario in which it can be degraded by light in the room is if you had lights on equipment pointed at the screen. This would significantly elevate your black levels, but not really affect your white levels, thus degrading your On/Off CR. Darin mentions this in his article as well. Of course in that instance controlling that light shouldn't be too difficult. Otherwise, wall brightness and color will affect your white point and ANSI CR, which are arguably just as important as On/Off.

[J Kildare]