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How Viewing Environment Conditions Can Corrupt Or Enhance Your Calibration - Page 3

post #61 of 108
Thread Starter 
You would need to try various lamps of a lower color temperature or apply colored filters to color correct the wall. In addition, you would need a color analyzer to confirm when you achieve CIE D65 or 6500K. If you want to eyeball it and just guess, try starting with a 5000K fluorescent with a high color rendering index (CRI). If your TV is calibrated, it could be used as a reference for comparing the color of illumination being reflected from the wall.

Wouldn't it be much more simple to paint just the wall behind the TV a complimentary shade of neutral gray or white? Neutral gray will not conflict with any other color in the room, even if the whole color scheme in the room is changed to redecorate. Then the TV will look more correct even when the room lights are on or the windows coverings are open during the day.

We are looking into an RGB LED solution that may have the fine adjustment capability that would enable calibratiion to compensate for non-neutral wall colors. This could be adjusted at the same time the TV is calibrated. It won't be inexpensive.

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

"Advancing the art and science of electronic imaging"
post #62 of 108
Thanks for the reply.

I might be up for some DIY LED projects.

(check out these LED arrays I made for my reef tank: http://www.worstkind.com/aquarium/2009/0502/leds01.jpg )

Question with LEDs in this application is how to diffuse the light evenly? I assume side emitting would be better than lambertian? And if so I'm not sure how a collimator type optic would be able to evenly blend RGB??

Interesting topic for sure.

Thanks
Ryan
post #63 of 108
Quote:


Wouldn't it be much more simple to paint just the wall behind the TV a complimentary shade of neutral gray or white?

not if you saw the look on my wife's face when I mentioned this hypothetical solution
post #64 of 108
Thread Starter 
Quote:


Question with LEDs in this application is how to diffuse the light evenly? I assume side emitting would be better than lambertian? And if so I'm not sure how a collimator type optic would be able to evenly blend RGB??

That's one reason why fluorescents are still superior for many applications. They are naturally very diffused and offer high light output at relatively low cost.
Quote:


not if you saw the look on my wife's face when I mentioned this hypothetical solution

How much education was the mention preceded by? Women are biologically more sensitive to color differences than men. They can obsess over the subtle differences in shades of pink lipstick or shades of brown hair color. The fashion and makeup industries know well how certain colors of their products can be unflattering alongside various colors of complexion and hair. These issues are not necessarily instinctive or intuitive for women. They still must be taught the principles involved to be fully aware.

I'm not really very surprised when anyone fails to see the importance of viewing environment conditions in a video system. It seems to be the last element of good system design to be genuinely comprehended or valued, even by some ISF and THX grads. Human perceptual factors make the viewer as much a component in the system as any other element, and thereby the room conditions.
post #65 of 108
Good point. I didn't really go into detail explaining it.... In fact she was already a bit annoyed that I spent all weekend reading the AVS forums

We only just had the room painted a week ago so maybe she just needs time to enjoy it first shes not very picky when it comes to picture quality like I am so I don't think a technical explanation will work. She will just use the generic "you're overthinking it" response


....BUT, I think a neutral grey wall would look cool there.... I might resort to a 3D-rendering mockup since in my experience showing her something is a much better method of persuasion than trying to explain something technical.

Thanks again.
post #66 of 108
Is there a way to calibrate the 10% light output using the AVS HD 709 dvd/mp4?
post #67 of 108
GeorgeAB,

I wasn't able to convince my wife we needed a white or gray wall behind the TV.... however I did do some 3D mockups and she liked the look of a white acrylic panel behind the TV, about 12" bigger in all directions (kinda integrates with the 'modernish' cabinets that will surround the TV).

Do you think having a foot-wide white border would do much? This acrylic panel could easily house a light behind it at night to make a neutral gray backdrop.
post #68 of 108
Thread Starter 
That sounds like it could be beneficial. I'm not confident I understand fully how this would be implemented, though.
post #69 of 108
maybe its a bit bizzare but this is the general idea.



I have some spare 6500k CREE Q5 LEDs from a recent project and a local acrylic shop that cuts to size so it should be fairly quick to prototype. probably easier with fluorescents though. But for the LEDs there are some fairly cheap elliptical optics out there to try (46 x 9 degree).


The powersource would be wired to a potentiometer to tweak the brightness.
Sorry don't mean to derail the thread too much into DIY.
post #70 of 108
Thread Starter 
It looks workable. Have fun.
post #71 of 108
Quote:
Originally Posted by Ictusbrucks View Post

maybe its a bit bizzare but this is the general idea.

I have some spare 6500k CREE Q5 LEDs from a recent project and a local acrylic shop that cuts to size so it should be fairly quick to prototype. probably easier with fluorescents though. But for the LEDs there are some fairly cheap elliptical optics out there to try (46 x 9 degree).


The powersource would be wired to a potentiometer to tweak the brightness.
Sorry don't mean to derail the thread too much into DIY.

I was thinking of the same thing but with black. I'd like to use something to surround the TV without painting. Just haven't figured it out yet. So I guess shivers are running threw spines right now with my color scheme but I like the Tuscan look and the real color is no where near the orange you see here.



post #72 of 108
So would this work or is my color choice on the walls too overpowering?
post #73 of 108
Thread Starter 
It's usually hard to illuminate black. The wall color interference will be reduced by your attempted surround treatment nearer the display.
post #74 of 108
Thread Starter 
The use of the technique of bias lighting has the perceptual effect of improving the contrast performance of televisions. Improved contrast in an image also has the beneficial effect of making the image appear to have greater sharpness.

I was reminded of these benefits while reviewing an article from the 'SMPTE Journal,' November of 2002. The title of the article was 'The Importance of Contrast and its Effect on Image Quality' by Segler, Pettitt and Kessel. Here are some pertinent quotes from the article:

"Contrast could be considered to be the most significant quality that impacts not only the perceived depth of an image, but also affects the apparent sharpness.....While the luminance level of a given image affects how the eye perceives contrast and detail, the ambient conditions surrounding the image can also have a dramatic impact. This phenomena was studied by Bartleson and Breneman (1967) to examine the impact of perceived contrast based not only on the luminance level of the image but taking into account the surrounding ambient luminance levels as well. Their results showed that the perceived contrast increased as ambient luminance increased. With the increase in ambient luminance, the eye interprets black levels as being darker while the impact to the white level is minimal. Since the perceived difference in dark areas is greater under the higher ambient luminance conditions, the perceived contrast is higher. It is a natural tendency to want low ambient luminance levels to strive for "better" perceived image quality and what is thought to result in higher contrast. However, in reality, the opposite is true. This tendency may be justified for current direct view CRT televisions due to the issue of glare that results from the glossy surface of the glass tube [also true for certain flat panel displays today]. With less ambient luminance, the glare is reduced- but it may be important to keep some ambient luminance behind the television [as in the case of bias lighting] to keep the perceived contrast higher.....While sharpness can affect the apparent contrast of an image, the converse is true in that contrast can also impact the apparent sharpness of an image. Images that have lower contrast will appear to be not as sharp as an image of the same content, but with higher contrast.....A subjective study was then conducted to verify the impact that ambient lighting has on perceived contrast. Several non-technical (and thus presumably non-biased) and technical observers were asked to compare a series of images with various ALL [average luminance levels] under different ambient luminance extremes in order to understand the impact that ambient viewing conditions might have on the perceived contrast between the two television technologies [CRT and DMD (DLP RPTV)]. Under dark ambient conditions, the result for images with an ALL > 5% was found to be equal between the CRT and the first DMD display. However, under bright ambient conditions (about 250 nits of luminance on the wall behind all of the units), the DMD display was favored over the CRT by 50% of the observers as having higher perceived contrast.....This proved that ambient conditions have the effect of potentially raising the black level threshold of the eye above the actual black level of the television such that the perceived contrast ratio is higher."

Here's another related reference from: 'Color Appearance Models,' by Mark D. Fairchild, Ph.D., of the Chester F. Carlson Center for Imaging Science: Munsell Color Science Laboratory.

"Their experimental results, obtained through matching and scaling experiments, showed that the perceived contrast of images increased when the image surround was changed from dark to dim to light. This effect occurs because the dark surround of an image causes dark areas to appear lighter while having little effect on light areas (white areas still appear white despite changes in surround). Thus since there is more of a perceived change in the dark areas of an image than in the light areas, there is a resultant change in perceived contrast.....Often, when working at a computer workstation, users turn off the room lights in order to make the CRT display appear of higher contrast. This produces a darker surround that should perceptually lower the contrast of the display. The predictions of Bartleson and Breneman are counter to everyday experience in this situation. The reason for this is that the room lights are usually introducing a significant amount of reflection off the face of the monitor and thus reducing the physical contrast of the displayed images. If the surround of the display can be illuminated without introducing reflection off the face of the display (e.g., by placing a light source behind the monitor that illuminates the surrounding area), the perceived contrast of the display will actually be higher than when it is viewed in a completely darkened room."

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

"Advancing the art and science of electronic imaging"
post #75 of 108
Good news: I received my Ideal Lume Panelight! So excited to put it on.

Bad News: One of the components is broken. I believe it goes onto the light itself but I am not sure what it does. What does it actually do and is it important?

In any case, I will be emailing to let them know and hopefully get another one soon.
post #76 of 108
Thread Starter 
Sorry about the problem. Please e-mail your order info to our office. We'll file the shipping damage claim for you and send out what was broken tomorrow. Hang on to the original packaging in case the UPS driver wants to inspect it.
post #77 of 108
Thread Starter 
Oh, yeah. We'll need to know what was damaged, as well.
post #78 of 108
Thread Starter 
Here's a neat optical illusion that graphically illustrates how adjacent colors can skew our color perception: http://www.avsforum.com/avs-vb/showt...1#post16766171 .
post #79 of 108
Long time lurker second time poster. First off good information guys, always good to get my knowledge on this kind of stuff up.
Secondly im from New Zealand and was wondering if anyone knew of any places in New Zealand where i could buy any of the aforementioned lighting sets. I've searched everywhere to no avail. Any help is greatly appreciated.
post #80 of 108
Thread Starter 
My company has shipped to customers in NZ in the past but the power system is different, requiring a voltage converter. There should be the basic component parts in your country or available online from a vendor closer to you than the US. Just look for high CRI fluorescents at 6500K.

I have yet to test any commercially available white LEDs closer than 7500K, even when the provider claims 6500K. One recent sample (last week) of white LED rope light was from a company that emphatically insists their diode supplier gives them LEDs that are between 6000K and 6500K. I ordered a sample and measured it with my spectroradiometer under controlled conditions. It measured at 8000K.
post #81 of 108
George,

I am uncertain whether I will put the Pioneer 500M on a stand about 5 " from the wall or on the wall mount.

If I get the panellight to allow for the latter situation, can the amount of light being displaced be controlled so as to be able to use it if I choose to mount away from the wall?

I have this color behind the TV: http://www.icipaints.co.uk/servlet/C...ame=30bb_16031

The rest of the room is this color: http://www.thegrovefurniture.com/gf018.html

The ceiling remains white though I do have a large Oatmeal acoustic panel that I could put up inbetween the TV and the seating area which would prevent direct reflection from overhead.

I hope this makes sense

I have a calibration coming up in a week or so and I want to have all the pieces in place ready for that day (I don't actaully have the TV yet - Monday).

Sincerely,

Morris
post #82 of 108
Thread Starter 
Personally, I consider wall mounting of flat TVs to be a fad that results in compromised viewing conditions for most people. Bias lighting with the Ideal-Lume Panelight product can be used in either case, but is less easy to get even distribution with wall mounting. Your color scheme looks fine. Be sure to use a matte finish. You are welcome to contact the company directly if you need any additional assistance.
post #83 of 108
Thank you George. Flat Matte finish used and panelight on the list of things to order.
post #84 of 108
forever....

your place is fantastic. I really like the "look" and "feel" of it. Must be a very relaxing and constructive space to record in. I would think yours to be a model of what home reccors could do with their setups.
post #85 of 108
Can someone explain exactly what the "baffle tube" looks like to adjust the blockage of light? Is it the thin black strip that is inserted into the tube with the bulb? If not, I think it may have not been shipped.
post #86 of 108
Thread Starter 
Here's a quote from the info sheet included with the product: "Ideal-Lume's output can be reduced by simply rotating the included light baffle tube around the lamp." The baffle tube is shipped already in place around the fluorescent lamp. If it's not there, that would be highly irregular, but not impossible.
post #87 of 108
Q: If I don't have any eye strain issue with dark room viewing, is it still worthwhile to put in a bias lighting? I'm concerned about not being able to see shadow details with smaller eye iris and unneutral reflections off my beige colored wall.

Q: If I want to measure brightness and color of the bias light, what is the correct way to do it? Should I hold the colorimeter in the air next to my plasma TV and point it towards the wall?

TIA
post #88 of 108
Thread Starter 
Quote:
Originally Posted by mmoh00 View Post

Q: If I don't have any eye strain issue with dark room viewing, is it still worthwhile to put in a bias lighting? I'm concerned about not being able to see shadow details with smaller eye iris and unneutral reflections off my beige colored wall.

Q: If I want to measure brightness and color of the bias light, what is the correct way to do it? Should I hold the colorimeter in the air next to my plasma TV and point it towards the wall?

TIA

Q#1: Please review the following post and draw your own conclusion: http://www.avsforum.com/avs-vb/showthread.php?t=1162578

Q#2: Yes, or use a visual comparison with the correct test pattern for ambient light level from the 'Avia' or 'Digital Video Essentials' series of optical disc programs.
post #89 of 108
Is it OK to put a piece of folded paper or something between the baffle tube and the plastic bulb fixture so as to hold the baffle tube in place?

The baffle tube is quite loose (on mine anyway) and simply turning the light on/off can affect it's position. Dusting aswell is problematic. This means I need to reset the illumination every few days.

I'd really like to just set and forget.

Thanks.
post #90 of 108
Thread Starter 
You are the first customer to have stated such a problem since we started using the baffle tubes. It would better to use something less flammable than paper. Perhaps a small piece of electrical tape?
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