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If you're very accustomed to it, you can probably notice when color temperature is considerably off. Human vision is not capable of determining these things with any kind of precision. Human senses tend to be highly relative to their surroundings, rather than absolute as a test instrument is. We're sensitive to small differences between colors, but are essentially not capable of making absolute judgements. A trained observer is better at it than an untrained observer, but all are subject to human limitations.

The only way to be sure is by use of a test instrument, either a colorimeter or spectroradiometer.

Of course, there is no device that can measure color - as color is a perception. We can measure light and spectral power distribution and based on that and a statistical model derived from observers, estimate color.
 

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A little history might help. This was taught in the early days of the Imaging Science Foundation courses. In the CRT days displays had a difficult time producing a very bright white without going non-linear. The white point of D65 was settled on because it was considered as far up on the Kelvin scale as practical before most viewers would recognize it as being blue-ish white. A slightly blue-white is perceived as brighter than a more neutral white, such as the CIE equal energy point on the chromaticity diagram (x-0.333, y-0.333, approx. 5455K).

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

"Advancing the art and science of electronic imaging"
 

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I know mine has never looked very good when it's too warm.It's washed out,less clear.
A white sheet of paper under overcast sky would give you a very rough idea what D65 looks like.

However, colour temperature governs how warm or cool the screen looks. If your screen looks washed out, it's most likely caused by settings other than the colour temperature.
 

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A white sheet of paper under overcast sky would give you a very rough idea what D65 looks like.

However, colour temperature governs how warm or cool the screen looks. If your screen looks washed out, it's most likely caused by settings other than the colour temperature.
Way too rough for any practical use. Paper is rated for "brightness" by how blue the paper is. Sunlight varies in color temperature by constantly changing factors, among which are: color of nearby reflecting surfaces (such as house paint, the color of clothing being worn by the person holding the paper, tree leaves, etc.), how dense the cloud cover is, altitude, background color framing the paper (such as holding it over a lawn, concrete, etc.), etc.

Here's a "sticky" thread from the top of this section of the forum that includes some good links for more detail on these issues:

'How Viewing Environment Conditions Can Corrupt Or Enhance Your Calibration.'

http://www.avsforum.com/avs-vb/showthread.php?t=849430
 

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GeorgeAB;33505986]Way too rough for any practical use.
That's why I said very rough, including the emphasis. The OP was asking about "recognizing D65 without a meter". Do you have any suggestions?
 

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That's why I said very rough, including the emphasis. The OP was asking about "recognizing D65 without a meter". Do you have any suggestions?
My suggestion would be to put what that "guy on the net said" out of his mind and study what has been offered in this thread. I still "like" post #2 , by nuke, as a suitable analysis of the issue in brief.

A human observer requires an objective reference to reliably evaluate and identify subtleties of color. The only objective reference professionals have used, before color meters became available, was optical comparators. Those devices couldn't be as precise as modern meters. They were used to adjust gray scale in the 6500K region, not the CIE D65 white point. There are old threads somewhere on this forum dedicated to building an optical comparator less costly than a meter.
 

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As a note I have an X-rite i1Display Pro (ID3). I had some question about the calibration, in particular the amount of blue it was measuring. I did an experiment. I have a X-rite Passport which has neutral white/gray sheets. I used one of those outside in bright sunlight and measured the reflected color off of the sheet with the iD3. The result was very close to 6500K. Again not completely accurate, but perhaps a good gut check that the meter is not way off.
 

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Most photography shops will have an 18% reflectance photo gray card in stock. They are readily available from online photography supply vendors as well. This is probably the least expensive and reliable objective reference for neutral gray widely available.
 

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As a note I have an X-rite i1Display Pro (ID3). I had some question about the calibration, in particular the amount of blue it was measuring. I did an experiment. I have a X-rite Passport which has neutral white/gray sheets. I used one of those outside in bright sunlight and measured the reflected color off of the sheet with the iD3. The result was very close to 6500K. Again not completely accurate, but perhaps a good gut check that the meter is not way off.
Your I1D3 will work pretty darn well out of the box with the Sony KDL42V4100. Just pick CCFL LCD as the display type and it should match it really well to D65.

If you have a display with one of the more advanced backlight technologies, they might not jibe up as well as there are no spectral correction data files for quantum dots and some other newer technologies yet.

Another way to visually compare is to use a photographic viewing box with known and calibrated D65 lamps in it and a grey chart. You can put that right next to the display and eyeball it by comparison and get pretty close.
 

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Most photography shops will have an 18% reflectance photo gray card in stock. They are readily available from online photography supply vendors as well. This is probably the least expensive and reliable objective reference for neutral gray widely available.
An instructor from X-Rite indicated to me that Gray Cards are designed to give 18% reflectance measurement. That is their main usage.

They are not necessarily 100% neutral gray, but may be close. They will vary and can only be confirmed to be neutral by a densitometer.
 

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An instructor from X-Rite indicated to me that Gray Cards are designed to give 18% reflectance measurement. That is their main usage.

They are not necessarily 100% neutral gray, but may be close. They will vary and can only be confirmed to be neutral by a densitometer.
Next up, then, would be a Munsell neutral value sample from X-Rite, or a smaller format gray scale sample set.
 

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nuke,

The portable pro-grade light boxes with D65 option, as you describe, have been rather expensive in my past investigation. Here's a typical recent example: http://www.colorhq.com/Judge-IIS-Portable-Viewing-Booth-p/jus50u30a.htm

A spectro and software can be had for less.
Yeah, I borrowed one from my company's graphics arts group, recent calibration sticker and everything. The IT department wouldn't loan me a CS2000 though. ;-)

But the I1D3 should be pretty darned close on a simple CCFL LCD tv right out of the box, just picking the right display type.
 

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An instructor from X-Rite indicated to me that Gray Cards are designed to give 18% reflectance measurement. That is their main usage.

They are not necessarily 100% neutral gray, but may be close. They will vary and can only be confirmed to be neutral by a densitometer.
Next up, then, would be a Munsell neutral value sample from X-Rite, or a smaller format gray scale sample set.


The problem though, for the OP, is that these cards depend on the illumination around them. An I1Pro has an internal light source, but the I1 Display Pro, is a colorimeter and can't directly measure reflective media.

He needs a true neutral grey card -and- a source of D65 light to illuminate it.
 

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Discussion Starter · #19 ·
Thanks for the replies.im gonna stick with the iPad being my reference.It actually does help as its a reference.Nothing else I've ever tried has ever made me "stop adjusting it too get it a little better".
 

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The problem though, for the OP, is that these cards depend on the illumination around them. An I1Pro has an internal light source, but the I1 Display Pro, is a colorimeter and can't directly measure reflective media.

He needs a true neutral grey card -and- a source of D65 light to illuminate it.
A light source close enough for eyeballing a 6500K gray scale would be a 90 CRI or better fluorescent lamp at that color temperature. The Ideal-Lume Pro uses a lamp from X-Rite that has a seven phosphor, D65 formula, patented by GretagMacbeth. It's the lamp used in X-Rite's light boxes. Here's a link to an assortment of bare lamps: http://cinemaquestinc.com/65k.htm . In the I-L Pro it's filtered to bring it's white point closer to video D65.

The CIE D65 daylight simulator specifications are not very tight on white point tolerance. They allow about +/- 1000K when it applies to white point. That's a visible color deviation when applied to video gray scale.
 
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