Advise on cheap bias lighting solution? - AVS Forum
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post #1 of 29 Old 03-28-2012, 03:47 PM - Thread Starter
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Hello everyone,

I am really interested in getting a bias light for my Pioneer Kuro plasma tv. I am not looking to spend a lot of money, but I want to have it be as close to perfect as I can get.

A lot of people have recommended Ideal Lume and I am open to getting that in the future, but for now I want something that I can put together for under $50.

I want the light to be as neutral as possible and support the perfect calibration and color rendition as well as provide just the right amount of ambient light.

What would you suggest?

Is there the perfect kind of light that I could purchase from, say, home depot that would work ideally for home theater?

Some other sites have suggested getting lights designed for fish tanks as they tend to be very neutral and work better for these purposes.

In this link, the author seems to have achieved almost ideal results using a Philips AquaSky bulb:

biaslighting dot blogspot dot com

I am certainly open to getting that, but I would prefer it if I could find it somewhere locally as opposed to having to order it.


Another thing I find interesting is that Ideal Lume sells only the bulbs from their sets rather cheaply. What if I bought the bulb and used it in another fixture? Would that provide the same level of performance as the Ideal Lume complete set?

I would think most of the performance would be in the bulb itself vs the fixture.

The bulbs can be purchased for about $12 to $15 a piece, but the complete set can be had for $60 to $100.

What do you think? Could I simply purchase the Ideal Lume bulb? Or should I get the Philips Aquasky as suggested in the link?

Another question. Should I get a dimmer to be able to adjust the brightness of the bias lighting?


Please let me know what you guys think.

Any suggestions are very much appreciated.
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post #2 of 29 Old 03-28-2012, 07:13 PM
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Dimmers won't work with fluorescent bulbs like the ones in the Idealume.

Make sure the wall behind your TV is a neutral white, gray, or black if possible, because even if you have a perfect light if you bounce it off a colored wall a good bit of the trouble you went to to get the color calibrated bulb will be wasted.

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post #3 of 29 Old 03-28-2012, 08:51 PM
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Quote:
Originally Posted by Chad B View Post

Dimmers won't work with fluorescent bulbs like the ones in the Idealume.

Make sure the wall behind your TV is a neutral white, gray, or black if possible, because even if you have a perfect light if you bounce it off a colored wall a good bit of the trouble you went to to get the color calibrated bulb will be wasted.

Conventional light dimmers don't work right with fluorescents. They typically cause flicker. Special ballasts are required to correctly dim fluorescent lamps and they are very expensive. Special dimming controls are also required to operate the dimming ballasts. They are very expensive as well.

Black isn't recommended with or without bias lighting. It's difficult to illuminate black sufficiently. When viewed with room lighting, a black surround diminishes perceived contrast of the image on the screen. A neutral white or neutral gray wall preserves correct color perception of the image on the screen. This principle also helps when using full room lighting. This technical article explains why this is important: 'The Importance Of Viewing Environment Conditions In A Reference Display System.'

There are T8 lamps (eight eighths of an inch in diameter) available from lighting suppliers, with a color rendering index (CRI) of 98 out of 100. The appropriate fixtures are not too difficult to find, either. Some method will need to be devised to shutter the illumination down as needed to provide illumination off the wall, so that it is 10% of the peak white of the TV, once the picture controls are adjusted for dark room conditions.

A "perfect" solution is not available. Achieving a near ideal solution typically requires thoroughly understanding the principles of the technique, time, effort, the right materials, and a modest amount of experimentation. The closest lamp to the practical ideal for bias lighting is the T12, seven phosphor, D65 lamp my company uses in our professional product. Even then, we incorporate color correction in the product to approach the correct white point for video. T12 fixtures of the right size are not nearly as common as T8.

Best regards and beautiful pictures,
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A Lion AV Consultants affiliate

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post #4 of 29 Old 03-28-2012, 09:20 PM - Thread Starter
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Originally Posted by GeorgeAB View Post

Conventional light dimmers don't work right with fluorescents. They typically cause flicker. Special ballasts are required to correctly dim fluorescent lamps and they are very expensive. Special dimming controls are also required to operate the dimming ballasts. They are very expensive as well.

Black isn't recommended with or without bias lighting. It's difficult to illuminate black sufficiently. When viewed with room lighting, a black surround diminishes perceived contrast of the image on the screen. A neutral white or neutral gray wall preserves correct color perception of the image on the screen. This principle also helps when using full room lighting. This technical article explains why this is important: 'The Importance Of Viewing Environment Conditions In A Reference Display System.'

There are T8 lamps (eight eighths of an inch in diameter) available from lighting suppliers, with a color rendering index (CRI) of 98 out of 100. The appropriate fixtures are not too difficult to find, either. Some method will need to be devised to shutter the illumination down as needed to provide illumination off the wall, so that it is 10% of the peak white of the TV, once the picture controls are adjusted for dark room conditions.

A "perfect" solution is not available. Achieving a near ideal solution typically requires thoroughly understanding the principles of the technique, time, effort, the right materials, and a modest amount of experimentation. The closest lamp to the practical ideal for bias lighting is the T12, seven phosphor, D65 lamp my company uses in our professional product. Even then, we incorporate color correction in the product to approach the correct white point for video. T12 fixtures of the right size are not nearly as common as T8.

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

"Advancing the art and science of electronic imaging"

I appreciate the response. Do the Ideal Lume full kits have a method of dimming the light to 10% of the peak white of a display?

Is it possible to buy just the bulb from your company and use it in a common fixture? What would be the disadvantage to doing this versus buying the full set? I mean, I could buy the T12 lamp for the Ideal Lume Pro for $24.

Lets say I do not buy any product from Ideal Lume. How close to the quality could I get by shopping at lighting stores and buying separate parts locally?

Do you have any opinion on the Philips AquaSky or other lamps designed for aquariums?

And, finally, my plasma tv is actually situated in front of a window and curtains are behind the display at this time. I am sure this is not an ideal location for bias lighting. I might move the display in the future. But I do not have walls that are a neutral gray. And I don't think painting the walls will be possible at the moment.

What do you think about getting neutral gray curtains that would reflect the bias lighting? Is that a feasible solution? I certainly think it would be an easier solution than painting the walls and I wouldn't have to move the tv.

Even if it isn't the ideal solution, do you think there could be some neutral gray colored cloth or other surface that could be placed behind the tv that could better reflect the bias lighting?

Do you have any ideas or recommendations for such a thing?

Thanks.
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post #5 of 29 Old 03-28-2012, 09:31 PM
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Many people use the dioders from ikea and are very pleased with the results.
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post #6 of 29 Old 03-28-2012, 09:37 PM
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Originally Posted by Doc. View Post

Many people use the dioders from ikea and are very pleased with the results.

The Ikea Dioder LEDs are the wrong color for video.
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post #7 of 29 Old 03-28-2012, 09:52 PM
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Originally Posted by GeorgeAB View Post

The Ikea Dioder LEDs are the wrong color for video.

So not to defend the Ikea lights, but I'm very curious about your assertion that D65 is the proper color for video. I've read a lot of the threads on the subject around here, and I've seen your laundry list of companies that use D65 lights, but that doesn't really answer my question. As far as I can tell, there is nothing in the Rec.709 spec that specifies the expected ambient white point. I know there is in the sRGB spec, but there it's explicitly D55 ambient. Where are you getting it from (and where did everyone else get it from) that D65 is the right thing to use?
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post #8 of 29 Old 03-28-2012, 09:52 PM
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Quote:
Originally Posted by jrodefeld View Post

I appreciate the response. Do the Ideal Lume full kits have a method of dimming the light to 10% of the peak white of a display?

Is it possible to buy just the bulb from your company and use it in a common fixture? What would be the disadvantage to doing this versus buying the full set? I mean, I could buy the T12 lamp for the Ideal Lume Pro for $24.

Lets say I do not buy any product from Ideal Lume. How close to the quality could I get by shopping at lighting stores and buying separate parts locally?

Do you have any opinion on the Philips AquaSky or other lamps designed for aquariums?

And, finally, my plasma tv is actually situated in front of a window and curtains are behind the display at this time. I am sure this is not an ideal location for bias lighting. I might move the display in the future. But I do not have walls that are a neutral gray. And I don't think painting the walls will be possible at the moment.

What do you think about getting neutral gray curtains that would reflect the bias lighting? Is that a feasible solution? I certainly think it would be an easier solution than painting the walls and I wouldn't have to move the tv.

Even if it isn't the ideal solution, do you think there could be some neutral gray colored cloth or other surface that could be placed behind the tv that could better reflect the bias lighting?

Do you have any ideas or recommendations for such a thing?

Thanks.

All the features, functions and capabilities of the various Ideal-Lume models are provided on our web site.

The only potential disadvantage of substituting another fixture is that it will possibly not be of the same quality as the thoroughly proven solutions we provide.

The quality of results you will get from accumulating your own materials will depend on the quality of the components you select.

If you use aquarium lamps, they will need to have a color temperature of 6500K, and a CRI of 90 or better, to work best with a video display.

A neutral white to gray surround is the recommendation. Cloth is fine. You would not have to paint all the walls in the room anyway, just behind the TV.
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post #9 of 29 Old 03-28-2012, 10:00 PM
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Originally Posted by ams2990 View Post

So not to defend the Ikea lights, but I'm very curious about your assertion that D65 is the proper color for video. I've read a lot of the threads on the subject around here, and I've seen your laundry list of companies that use D65 lights, but that doesn't really answer my question. As far as I can tell, there is nothing in the Rec.709 spec that specifies the expected ambient white point. I know there is in the sRGB spec, but there it's explicitly D55 ambient. Where are you getting it from (and where did everyone else get it from) that D65 is the right thing to use?

The following sources are from the "sticky" thread in the 'Links to this forum's popular threads' section at the top of this sub-section of the forum: 'D65 Video Bias Lighting- Fundamental Theory And Practice'
http://www.avsforum.com/avs-vb/showthread.php?t=1162578 :

SMPTE Recommended Practices document: RP166-1995: ‘Critical Viewing Conditions For Evaluation Of Color Television Pictures’

ITU-R BT.710-4 'Subjective Assessment Methods For Image Quality In High-Definition Television'

ISO 17121:2000: 'Cinematography -- Work stations used for film and video production -- Requirements for visual and audio conditions'

"Monitor white reference: In additive mixture, the illumination of the reproduced image is generated entirely by the display device. In particular, reproduced white is determined by the characteristics of the display, and is not dependent on the environment in which the display is viewed. In a completely dark viewing environment, such as a cinema theater, this is desirable; a wide range of chromaticities is accepted as “white.” However, in an environment where the viewer’s field of view encompasses objects other than the display, the viewer’s notion of “white” is likely to be influenced or even dominated by what he or she perceives as “white” in the ambient. To avoid subjective mismatches, the chromaticity of white reproduced by the display and the chromaticity of white in the ambient should be reasonably close." from Charles A. Poynton's, 'Digital Video and HDTV Algorithms and Interfaces'
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George is there ant place to get Ideal-lume standard in Canada? I want to buy one of these but over $40 for shipping is steep.
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post #11 of 29 Old 03-28-2012, 10:23 PM
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Originally Posted by Doc. View Post

George is there ant place to get Ideal-lume standard in Canada? I want to buy one of these but over $40 for shipping is steep.

We don't have any official Canadian dealers. Do you live near the US border?
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Yes i do,I guess that is an option.
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post #13 of 29 Old 03-28-2012, 10:45 PM
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Originally Posted by GeorgeAB View Post

The following sources are from the "sticky" thread in the 'Links to this forum's popular threads' section at the top of this sub-section of the forum: 'D65 Video Bias Lighting- Fundamental Theory And Practice'
http://www.avsforum.com/avs-vb/showthread.php?t=1162578 :

SMPTE Recommended Practices document: RP166-1995: Critical Viewing Conditions For Evaluation Of Color Television Pictures'

ITU-R BT.710-4 'Subjective Assessment Methods For Image Quality In High-Definition Television'

ISO 17121:2000: 'Cinematography -- Work stations used for film and video production -- Requirements for visual and audio conditions'

"Monitor white reference: In additive mixture, the illumination of the reproduced image is generated entirely by the display device. In particular, reproduced white is determined by the characteristics of the display, and is not dependent on the environment in which the display is viewed. In a completely dark viewing environment, such as a cinema theater, this is desirable; a wide range of chromaticities is accepted as white. However, in an environment where the viewer's field of view encompasses objects other than the display, the viewer's notion of white is likely to be influenced or even dominated by what he or she perceives as white in the ambient. To avoid subjective mismatches, the chromaticity of white reproduced by the display and the chromaticity of white in the ambient should be reasonably close." from Charles A. Poynton's, 'Digital Video and HDTV Algorithms and Interfaces'

Interesting, thanks. I'll have to go find those documents. If I read Poynton's statement correctly, it implies that if you have a large enough TV that it occupies a sufficiently large portion of your eyes' viewing area, bias lighting is unnecessary.

Thanks again for the info.
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post #14 of 29 Old 03-28-2012, 10:52 PM
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Originally Posted by ams2990 View Post

Interesting, thanks. I'll have to go find those documents. If I read Poynton's statement correctly, it implies that if you have a large enough TV that it occupies a sufficiently large portion of your eyes' viewing area, bias lighting is unnecessary.

Thanks again for the info.

Where did he discuss the size of the image?
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post #15 of 29 Old 03-29-2012, 04:37 AM - Thread Starter
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Originally Posted by GeorgeAB View Post

All the features, functions and capabilities of the various Ideal-Lume models are provided on our web site.

The only potential disadvantage of substituting another fixture is that it will possibly not be of the same quality as the thoroughly proven solutions we provide.

The quality of results you will get from accumulating your own materials will depend on the quality of the components you select.

Aquarium lamps need to have a color temperature of 6500K and a CRI of 90 or better.

A neutral white to gray surround is the recommendation. Cloth is fine. You would not have to paint all the walls in the room anyway, just behind the TV.

Thanks for this response. I would very much like to get a neutral gray cloth or curtains to put behind the display.

Do you have any suggestions? I don't know where I could buy "color correct" cloth.

What do you think?
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post #16 of 29 Old 03-29-2012, 07:24 AM
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Quote:
Originally Posted by jrodefeld View Post

Thanks for this response. I would very much like to get a neutral gray cloth or curtains to put behind the display.

Do you have any suggestions? I don't know where I could buy "color correct" cloth.

What do you think?

Take a genuine neutral gray reference along with you for comparing the color of the cloth at any fabric store. The least expensive and/or commonly available gray reference would be an 18% reflectance photo gray card from a camera shop. It is not the particular shade of gray that is important, rather its neutrality (reflects all colors equally). Take it to a store window or out the door to compare under natural daylight if possible. Store lighting is usually not ideal for comparing colors. They may have suitable lighting for this task, but that would be rare. Patterned cloth is fine, if all the elements in the pattern are also neutral (white to black).
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post #17 of 29 Old 03-29-2012, 09:25 AM
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Originally Posted by GeorgeAB View Post

Where did he discuss the size of the image?

"However, in an environment where the viewer's field of view encompasses objects other than the display..."

If the TV is large enough, then ergo there won't be other objects in the field of view besides the display.
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post #18 of 29 Old 03-29-2012, 10:07 AM
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Quote:
Originally Posted by ams2990 View Post

"However, in an environment where the viewer's field of view encompasses objects other than the display..."

If the TV is large enough, then ergo there won't be other objects in the field of view besides the display.

The implication in the context is not that the screen does or doesn't fill the entire field of view, but that there is sufficient ambient illumination to recognize other objects in that field, versus a dark cinema.

In a typical commercial cinema, only the closest rows might provide a screen size that would fill an audience member's field of view. Such viewing distance is much closer than the ideal recommendation for 35mm film or 2k digital. The recommendation for ambient illumination in a viewing environment is reserved for emissive displays, not for front projection and cinema. Emissive displays are typically two to three times as bright as commercial cinemas, if not even more so. It's the brightness of the image that is the chief reason for recommending ambient lighting, not the prominence of the screen within the field of view. Poynton was addressing two viewing conditions, one without ambient lighting, and the other with ambient lighting.
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post #19 of 29 Old 03-30-2012, 02:19 AM
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Originally Posted by GeorgeAB View Post

The implication in the context is not that the screen does or doesn't fill the entire field of view, but that there is sufficient ambient illumination to recognize other objects in that field, versus a dark cinema.

In a typical commercial cinema, only the closest rows might provide a screen size that would fill an audience member's field of view. Such viewing distance is much closer than the ideal recommendation for 35mm film or 2k digital. The recommendation for ambient illumination in a viewing environment is reserved for emissive displays, not for front projection and cinema. Emissive displays are typically two to three times as bright as commercial cinemas, if not even more so. It's the brightness of the image that is the chief reason for recommending ambient lighting, not the prominence of the screen within the field of view. Poynton was addressing two viewing conditions, one without ambient lighting, and the other with ambient lighting.

Interesting. Assuming you had the option of being able to perfectly control the light level in the room, is a darker room with a movie-theater brightness screen in some way superior to a lighter room with a brighter display?
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post #20 of 29 Old 03-30-2012, 08:39 AM
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Originally Posted by ams2990 View Post

Interesting. Assuming you had the option of being able to perfectly control the light level in the room, is a darker room with a movie-theater brightness screen in some way superior to a lighter room with a brighter display?

It depends. There are many issues pertaining to the display technologies involved, the characteristics of the human visual system, and perceptual factors that must be understood and balanced with one another. Your question is probably worthy of its own thread, plus is moving pretty far afield of the original topic. An example is that much of the answer revolves around why movies are shot at 24 frames per second.
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post #21 of 29 Old 03-30-2012, 09:17 AM
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My bias light seems to be too bright. It's a typical CFL bulb with a 6500K rating and pretty high CRI. What's a good way to restrict it's light output safely?
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My bias light seems to be too bright. It's a typical CFL bulb with a 6500K rating and pretty high CRI. What's a good way to restrict it's light output safely?

extra layers of diffuser or some kind of tint film? generally its easier to just get a lower wattage light, you can't dim the things as said.

i guess you could build some kind of mask with slits or grates to lower output, or simply paint out part of the bulb cover.

been looking for a cheaper alternative, doesn't look to be much competition to the ikea dioder, also considering the effect of the red brick behind my tv
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post #23 of 29 Old 04-01-2012, 11:55 PM
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Originally Posted by PlasmaPZ80U View Post

My bias light seems to be too bright. It's a typical CFL bulb with a 6500K rating and pretty high CRI. What's a good way to restrict it's light output safely?

Buy a small black bucket and cut a suitable slot out of the side and mount it over the top of the light.
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post #24 of 29 Old 04-04-2012, 01:24 PM
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Originally Posted by PlasmaPZ80U View Post

My bias light seems to be too bright. It's a typical CFL bulb with a 6500K rating and pretty high CRI. What's a good way to restrict it's light output safely?

just got a new bulb

It's not too bright at 330 lumens but I can't find any CRI info.
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post #25 of 29 Old 04-04-2012, 02:00 PM
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Originally Posted by PlasmaPZ80U View Post

just got a new bulb

It's not too bright at 330 lumens but I can't find any CRI info.

What color of wall do you have?
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post #26 of 29 Old 04-04-2012, 02:01 PM
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Originally Posted by PlasmaPZ80U View Post

just got a new bulb

It's not too bright at 330 lumens but I can't find any CRI info.

I couldn't find any after a web search for additional info. It's probably not very good, based upon typical compact fluorescent samples I've researched over the last few years. They are rarely over 80 and frequently in the 65 to 75 CRI range. It's also somewhat telling that they don't mention a CRI rating at all. If it was superior, they would be proud to mention it.
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post #27 of 29 Old 04-04-2012, 03:37 PM
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Quote:
Originally Posted by GeorgeAB View Post

I couldn't find any after a web search for additional info. It's probably not very good, based upon typical compact fluorescent samples I've researched over the last few years. They are rarely over 80 and frequently in the 65 to 75 CRI range. It's also somewhat telling that they don't mention a CRI rating at all. If it was superior, they would be proud to mention it.

My CFL is rated at 80 (can't remember the brand) but it is darned near impossible to find a rounded, socket-based CFL at 90+.
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post #28 of 29 Old 04-04-2012, 04:37 PM
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The light output of this bulb is better than the one I was using previously (a closer match) and if the bulb has any tints to it, it would be on the blue side. My wall is a light peach color. Not optimal but still better than using no bias light at all, which I did do sometimes in the past because of my previous bulb being way too bright and distracting.
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post #29 of 29 Old 04-04-2012, 08:20 PM
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My bulb is rated at 5500k and illuminates an off-white wall/ceiling. Looking directly at the bulb it does have a slight blue hue to it but it's not noticeable (at least to us) when viewing the tv.
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