What am I doing wrong?

[Persia]

I have a calibrated monitor. To verify the calibration I compared picture of a color checker vs. my color checker passport. They look very similar. The first problem is that the same picture looks a little different in Light Room vs. other viewers for example DPP or Micrsoft Viewer. The picture of color checker is more close to the reality in the Light Room than DPP.

The second problem is that when I compare picture of the color checker taken with my 50D, the color are very lighter. I’m using a Sekonic L358 and also check the white patch to make sure the exposure is correct. I also corrected the white balance by clicking on a gray patch. If the exposure is reduced by about 1 stop the colors are close to real but with correct exposure they are lighter. I have tried different camera profiles and found that Adobe Standard gives the best result surely after one stop underexpose.

 

[BAK]

You write > I compare picture of the color checker taken with my 50D,

How did you make the picture of the color checker? Maybe the printing process is the problem?

BAK

 

[Persia]

I didn't print the picture. I compared it on the monitor.

 

[Joseph S Wisniewski]

I have a calibrated monitor. To verify the calibration I compared picture of a color checker vs. my color checker passport. They look very similar. The first problem is that the same picture looks a little different in Light Room vs. other viewers for example DPP or Micrsoft Viewer. The picture of color checker is more close to the reality in the Light Room than DPP.

That's normal. Lightroom is a color managed application, it actually uses the monitor profile you created to compute the proper colors to display. DPP and Microsoft viewer are not color managed, they don't actually use the profile, so their colors are off. The only benefit programs like that get from calibration is the "white point" setting.

A calibration program and calibrating device (EyeOne Display, Spyder, etc) do two things:

• calibration, which consists of getting the monitor to a "useful" state where it's "white point" matches a desired viewing situation. What that means is that the color of "white" that the monitor produces is equal to a specific color.

The monitor is "emissive", it's a "light maker". The only thing that affects the monitor is its own settings. If the computer tells the monitor to display a particular color, that's what it does. If you turn off the room lights, that color is still on the monitor.

Your passport is "reflective". It's not on the monitor. Its color is affected by the color of the room lights. Make the room lights warmer (more orange) and the passport looks warmer. Turn off the room lights, and the passport goes away.

So, if you told the calibrating program a color that doesn't match the room lights, the passport doesn't match the image seen on the screen.

There's another problem. There are multiple pictures of the Checker floating around the internet (as BAK mentioned). The only one that actually works for what you're trying to do is one that's computer generated (instead of photographed) in the L*A*B color space. Any ColorChecker picture in sRGB, Adobe RGB, or any picture that's a real "picture" (shot with a camera or scanned on a scanner) of the ColorChecker will be wrong. Plain and simple.

The second problem is that when I compare picture of the color checker taken with my 50D, the color are very lighter. I’m using a Sekonic L358 and also check the white patch to make sure the exposure is correct. I also corrected the white balance by clicking on a gray patch. If the exposure is reduced by about 1 stop the colors are close to real but with correct exposure they are lighter. I have tried different camera profiles and found that Adobe Standard gives the best result surely after one stop underexpose.

Of course. Part of that is probably simply the ColorChecker image you're using. If it's not LAB, the brightness will be wrong , guaranteed. 100%.

Even if it is LAB, if your calibration process didn't include adjusting the monitor brightness to exactly match the room lighting, the checker on the screen won't match the passport. If your lighting is dimmer than what you calibrated the monitor to, the image on the screen is too bright. An "extreme" example: turn off the room lights. The passport is now in the dark, and the image on the screen is many stops brigher than the passport.

Calibration really takes more than will fit in one little post, but I've given you a start.

wizfaq

--
Rahon Klavanian 1912-2008.

Armenian genocide survivor, amazing cook, scrabble master, and loving grandmother. You will be missed.

Ciao! Joseph

http://www.swissarmyfork.com

 

[Persia]

Thank you Joseph for the detailed answer.

I have another issue that I asked before but nobody could help me.

The problem is that when I use a grey card to correct the white balance, I get a yellow cast. I tried three different grey cards including the color checker and I viewed the pictures on four different monitors. For example when I take a portrait using flash, based on the grey card the color temperature should be around 5600, but I have to use a number between 5000-5200 to get a proper skin tone. I get a very yellow skin tone with the 5600 K.

Thank you in advance.

 

[Stephen Christie]

Most grey cards are 15% grey for film cameras a digital camera needs 18% grey cards for proper calibration.

Also, I find all forms of custom WB can be iffy at times.

I had lots of color calibration issues until I set my monitor to an adobe profile and my Light Room to Adobe Profile and my camera to adobe profile. Now I get the same colors everywhere and love the color!

Steve

Thank you Joseph for the detailed answer.

I have another issue that I asked before but nobody could help me.

The problem is that when I use a grey card to correct the white balance, I get a yellow cast. I tried three different grey cards including the color checker and I viewed the pictures on four different monitors. For example when I take a portrait using flash, based on the grey card the color temperature should be around 5600, but I have to use a number between 5000-5200 to get a proper skin tone. I get a very yellow skin tone with the 5600 K.

 

[Stephen Christie]

You also need to use Spot Metering on the cards.

-Steve

 

[Joseph S Wisniewski]

Most grey cards are 15% grey for film cameras a digital camera needs 18% grey cards for proper calibration.

I'm not sure where you picked that up, but it's totally wrong. Cameras can quite happily white balance from 90% or higher pure white cards, through 18% gray cards, or the 6% square on a color checker. The higher the percentage of reflectance, the more neutral the card typically is, a good white card is several times more accurate than an a8% gray card.

All else being equal, and manufactured to the same tolerances, an 18% card is going to be slightly more accurate than a 15% card.

Perhaps you confused a white card (85% reflectance, 15% absorption) with a 15% gray card.

Also, I find all forms of custom WB can be iffy at times.

That is quite true.

I had lots of color calibration issues until I set my monitor to an adobe profile and my Light Room to Adobe Profile and my camera to adobe profile. Now I get the same colors everywhere and love the color!

And that is good advice.

I take it you're talking about the use of the Adobe Profile Generator, and not just trying to set everything to Adobe RGB.

--
Rahon Klavanian 1912-2008.

Armenian genocide survivor, amazing cook, scrabble master, and loving grandmother. You will be missed.

Ciao! Joseph

http://www.swissarmyfork.com

 

[Stephen Christie]

I did mean the stock factory type AdobeRGB windows monitor profile and the camera adobe calibration choice in lightroom.

I have read many places (not forums) about 15% and 18% cards many places on the net even B&H sells both kinds and labels them 15% and 18% grey cards for digital cameras.

Steve

Most grey cards are 15% grey for film cameras a digital camera needs 18% grey cards for proper calibration.

I'm not sure where you picked that up, but it's totally wrong. Cameras can quite happily white balance from 90% or higher pure white cards, through 18% gray cards, or the 6% square on a color checker. The higher the percentage of reflectance, the more neutral the card typically is, a good white card is several times more accurate than an a8% gray card.

All else being equal, and manufactured to the same tolerances, an 18% card is going to be slightly more accurate than a 15% card.

Perhaps you confused a white card (85% reflectance, 15% absorption) with a 15% gray card.

Also, I find all forms of custom WB can be iffy at times.

That is quite true.

I had lots of color calibration issues until I set my monitor to an adobe profile and my Light Room to Adobe Profile and my camera to adobe profile. Now I get the same colors everywhere and love the color!

And that is good advice.

I take it you're talking about the use of the Adobe Profile Generator, and not just trying to set everything to Adobe RGB.

--

 

[maney gomes]

Can some body help me here, what is a checker and a passport, sample pictures for me to get an idea and where to get this stuff, my monitor could use some calibration...

Also, I have found that irfanview is very good at displaying images, if it looks good on irfanview, most likely it is correct.

I have a calibrated monitor. To verify the calibration I compared picture of a color checker vs. my color checker passport. They look very similar. The first problem is that the same picture looks a little different in Light Room vs. other viewers for example DPP or Micrsoft Viewer. The picture of color checker is more close to the reality in the Light Room than DPP.

That's normal. Lightroom is a color managed application, it actually uses the monitor profile you created to compute the proper colors to display. DPP and Microsoft viewer are not color managed, they don't actually use the profile, so their colors are off. The only benefit programs like that get from calibration is the "white point" setting.

A calibration program and calibrating device (EyeOne Display, Spyder, etc) do two things:

• calibration, which consists of getting the monitor to a "useful" state where it's "white point" matches a desired viewing situation. What that means is that the color of "white" that the monitor produces is equal to a specific color.

The monitor is "emissive", it's a "light maker". The only thing that affects the monitor is its own settings. If the computer tells the monitor to display a particular color, that's what it does. If you turn off the room lights, that color is still on the monitor.

Your passport is "reflective". It's not on the monitor. Its color is affected by the color of the room lights. Make the room lights warmer (more orange) and the passport looks warmer. Turn off the room lights, and the passport goes away.

So, if you told the calibrating program a color that doesn't match the room lights, the passport doesn't match the image seen on the screen.

There's another problem. There are multiple pictures of the Checker floating around the internet (as BAK mentioned). The only one that actually works for what you're trying to do is one that's computer generated (instead of photographed) in the L*A*B color space. Any ColorChecker picture in sRGB, Adobe RGB, or any picture that's a real "picture" (shot with a camera or scanned on a scanner) of the ColorChecker will be wrong. Plain and simple.

The second problem is that when I compare picture of the color checker taken with my 50D, the color are very lighter. I’m using a Sekonic L358 and also check the white patch to make sure the exposure is correct. I also corrected the white balance by clicking on a gray patch. If the exposure is reduced by about 1 stop the colors are close to real but with correct exposure they are lighter. I have tried different camera profiles and found that Adobe Standard gives the best result surely after one stop underexpose.

Of course. Part of that is probably simply the ColorChecker image you're using. If it's not LAB, the brightness will be wrong , guaranteed. 100%.

Even if it is LAB, if your calibration process didn't include adjusting the monitor brightness to exactly match the room lighting, the checker on the screen won't match the passport. If your lighting is dimmer than what you calibrated the monitor to, the image on the screen is too bright. An "extreme" example: turn off the room lights. The passport is now in the dark, and the image on the screen is many stops brigher than the passport.

Calibration really takes more than will fit in one little post, but I've given you a start.

wizfaq

--
Rahon Klavanian 1912-2008.

Armenian genocide survivor, amazing cook, scrabble master, and loving grandmother. You will be missed.

Ciao! Joseph

http://www.swissarmyfork.com

--
http://cloud.prohosting.com/~poder2k/photography

 

[maney gomes]

Okay,

I know how to setup my camera to AdobeRGB, Photoshop element I can also set it to adobe RGB, but how about the monitor, where did you get the adobe rgb for the monitor ?

Even if you set your monitor to Adobe RGB, you still have all the monitor controls to play with that you can set so that has an effect as well even if you have the same profile every where...

What I found that was messing up my system was that I had set PSE to also do color management and that was messing everything up. As soon as I told turned off color management on PSE, now everything is okay.

I use the Huey to calibrate my monitor.

I also set got a printed calibration sheet from MPIX to make my monitor more or less match their printers.

and I shoot on sRGB II and that seems to be working very well for me.

Most grey cards are 15% grey for film cameras a digital camera needs 18% grey cards for proper calibration.

Also, I find all forms of custom WB can be iffy at times.

I had lots of color calibration issues until I set my monitor to an adobe profile and my Light Room to Adobe Profile and my camera to adobe profile. Now I get the same colors everywhere and love the color!

Steve

Thank you Joseph for the detailed answer.

I have another issue that I asked before but nobody could help me.

The problem is that when I use a grey card to correct the white balance, I get a yellow cast. I tried three different grey cards including the color checker and I viewed the pictures on four different monitors. For example when I take a portrait using flash, based on the grey card the color temperature should be around 5600, but I have to use a number between 5000-5200 to get a proper skin tone. I get a very yellow skin tone with the 5600 K.

--
http://cloud.prohosting.com/~poder2k/photography

 

[maney gomes]

I take it you're talking about the use of the Adobe Profile Generator, and not just trying to set everything to Adobe RGB.

I have adobe photoshop element, can I generate an Adobe profile ?

Is that using the adobe Gamma software ?

I understood that he just used standard adobe RGB every where ?

 

[Joseph S Wisniewski]

I take it you're talking about the use of the Adobe Profile Generator, and not just trying to set everything to Adobe RGB.

I have adobe photoshop element, can I generate an Adobe profile ?

The Adobe DNG Camera Profile Editor generates camera profiles from photos of a Macbeth ColorChecker or PassPort.

You can use these with the raw converter (ACR 4 and ACR 5) in PhotoShop CS3 or CS4, but I'm not sure about using them with Elements. I don't know which versions of Elements use ACR 4 or ACR 5, or if the ability to select a profile in ACR is one of the abilities that you get with full PhotoShop but not with Elements.

Sorry.

Is that using the adobe Gamma software ?

Adobe Gamma software is an attempt at calibrating a monitor visually, and it's really horrid. Basically, there's no way to properly calibrate a monitor without a calibration device, like a Spyder or an EyeOne Display.

I understood that he just used standard adobe RGB every where ?

You can't do that.

Adobe RGB is a "working" color space. It's how PhotoShop or Elements stores and manipulates the colors in the image file.

But you need a "monitor profile" (generated by that Spyder or EyeOne Display I mentioned earlier) to "translate" from the image's Adobe RGB "numbers" to the numbers that display the right colors on your particular display.

And a printer profile to translate the image's numbers into the numbers the printer needs to produce those colors.

Hope this makes sense...

--
Rahon Klavanian 1912-2008.

Armenian genocide survivor, amazing cook, scrabble master, and loving grandmother. You will be missed.

Ciao! Joseph

http://www.swissarmyfork.com

 

[Joseph S Wisniewski]

Okay,

I know how to setup my camera to AdobeRGB, Photoshop element I can also set it to adobe RGB, but how about the monitor, where did you get the adobe rgb for the monitor ?

You don't. As I mentioned in my other reply to you, Adobe RGB is an "image color space". The camera takes images, PhotoShop edits images. They both know that 237 red, 118 green, 14 blue is a particular shade of orange that they could look up in a color standards book.

The monitor is a "device", it doesn't do pretty, mathematical profiles like Adobe RGB, it does it's own thing, as determined by its hardware. So you have to take a piece of hardware called a calibrator (I mentioned the Spyder and the EyeOne Display elsewhere), stick it on your monitor, and run a calibrating and profiling program, so your computer can analyze what your particular monitor can do. The calibration software generates a profile that matches your particular monitor.

The color management software inside PhotoShop (or Elements or Lightroom) can mathematically translate between the AdobeRGB profile and the ManeyMonitor profile, so that the 237 red, 118 green, 14 blue I mentioned earlier actually ends up looking like the "official" shade of orange that belongs to those Adobe RGB numbers.

Even if you set your monitor to Adobe RGB, you still have all the monitor controls to play with that you can set so that has an effect as well even if you have the same profile every where...

Except that you can't. No matter what you do with the monitor controls, it won't match the Adobe RGB color range. You really do need to use a calibration tool to measure what the monitor really can do, not hope you can twiddle controls to make it do Adobe RGB.

What I found that was messing up my system was that I had set PSE to also do color management and that was messing everything up. As soon as I told turned off color management on PSE, now everything is okay.

I use the Huey to calibrate my monitor.

That could be one of your problems.

Seriously, if you're calibrating properly, you never turn off color management in PSE. You tell it to use Adobe RGB for the image, and the profile that you generated with the Huey for the monitor, and you should be able to see reasonably correct colors.

I also set got a printed calibration sheet from MPIX to make my monitor more or less match their printers.

That's not really necessary, and will only cause visual mismatches. MPIX will also have a profile for their printer that you can set as the printer profile in PhotoShop (not sure about Elements) and then use a feature called "soft proofing" to see exactly what's going to get printed out.

and I shoot on sRGB II and that seems to be working very well for me.

Well, if you like what you're getting, then "works well for you", works.

--
Rahon Klavanian 1912-2008.

Armenian genocide survivor, amazing cook, scrabble master, and loving grandmother. You will be missed.

Ciao! Joseph

http://www.swissarmyfork.com

 

[Joseph S Wisniewski]

I did mean the stock factory type AdobeRGB windows monitor profile and the camera adobe calibration choice in lightroom.

There is no "AdobeRGB windows monitor profile".

I have read many places (not forums) about 15% and 18% cards

And yet, I (who appear to be much more well read than you) have never encountered one.

Google (who's more well read than either of us) hasn't heard of one, either.

• Google "15% gray card", you get 20 hits, none of which are actually for 15% , because Google doesn't search punctuation, so things like "Rule 15. Gray card" or "2009/11/15/gray-card" caused a handful of false matches.
• Google "18% gray card", and you get over 45,000 hits. I didn't check all 45,000, but the first 3 pages (30 links) are 100% solid, real hist for "18% gray card", not "18." or "18/".

many places on the net even B&H sells both kinds and labels them 15% and 18% grey cards for digital cameras.

OK, a quick look at B&H.

WhiBal - 75%

http://www.bhphotovideo.com/c/product/472220-REG/WhiBal_WB6PK_G6_Pocket_White_Balance.html#features

Digital Image Flow - B&H doesn't say, but Digital Image Flow says 63%

http://www.bhphotovideo.com/c/product/529527-REG/Digital_Image_Flow_DGK_2_Digital_Grey_Kard_.html#features

Delta - B&H doesn't say, but Delta says 18%

http://www.bhphotovideo.com/c/product/529527-REG/Digital_Image_Flow_DGK_2_Digital_Grey_Kard_.html#features

Lastolite - 18%

http://www.bhphotovideo.com/c/product/375202-REG/Lastolite_LL_LR2050_EZYBalance_Grey_White_Card_.html

Kodak - 18%

http://www.bhphotovideo.com/c/product/27715-REG/Kodak_1903061_Gray_Cards.html#features

X-Rite (Gretag Macbeth) - 18%

http://www.bhphotovideo.com/c/product/465298-REG/X_Rite_421868_ColorChecker_Mini_3_Step_Gray.html

Perfext-Pixs - B&H doesn't say, Perfect Pixs doesn't say either

http://www.bhphotovideo.com/c/product/532341-REG/Perfect_Pixs_PER3TONE_3_Tone_Gray_Card.html#features

QP - 35, 48, 80, and 95%

http://www.bhphotovideo.com/c/product/493034-REG/QP_Card_GQP102_4_Step_Gray_Scale_Card.html#features

QP (again) 18%

http://www.bhphotovideo.com/c/product/286667-REG/QP_Card_GQP101_Qp_Calibration_Card_101.html#features

Sekonic - 18%

http://www.bhphotovideo.com/c/product/159057-REG/Sekonic_401_807_Gray_Card.html#features

Novoflex - B&H doesn't say, Adorama says 18%

http://www.bhphotovideo.com/c/product/484055-REG/Novoflex_ZEBRA_XL_Zebra_Card_Extra_Large.html#features

Cameron - 18%

http://www.bhphotovideo.com/c/product/671140-REG/Cameron_1202061_20_Reference_18_Gray.html

In short:

• There are lots of 18% gray cards. Some labeled specifically for digital, like the X-Rite, Lastolite, or Novoflex, while others are basically unchanged from the film days, like Kodak or Delta.
• There are several newer cards that go to higher reflectance, anywhere from 35% to 95%. All of those are promoted as "digital".
• There are no 15% gray cards, from anyone, anywhere, because you raise reflectance to increase accuracy. You never, ever lower it.

So, go right ahead, use your nonexistent 15% gray card with your nonexistent "AdobeRGB windows monitor profile" for all the nonexistent pictures you like.

--
Rahon Klavanian 1912-2008.

Armenian genocide survivor, amazing cook, scrabble master, and loving grandmother. You will be missed.

Ciao! Joseph

http://www.swissarmyfork.com

 

[Stephen Christie]

I set ICC Monitor profile to AdobeRGB

Each operating system has a different way to change it, XP, Vista, win7.
if you need help learning how to do this go here:

http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/icm_change_color_profile_monitor.mspx

I keep my monitor ICC color management profile on: Adobe RGB 1998
On my camera I use: Adobe RGB
In Photoshop or Light Room I change the Camera Calibrationto: Adobe Standard

--
-Steve

 

[Joseph S Wisniewski]

I set ICC Monitor profile to AdobeRGB

No one said you couldn't set a monitor profile to AdobeRGB. You can set a monitor profile to any totally wrong profile you like. You can set it to Prophoto RGB. You can set it to Gray Gamma 20. You can set it to a printer profile. And, just like setting the monitor profile to AdobeRGB, any of those other profiles will also produce wrong results.

You said that there was an "AdobeRGB windows monitor profile". This is incorrect. Adobe RGB is a working profile, it does match the gamut of any existing monitor, and it does not contain a vcgt LUT for setting up a video card.

If you set your computer's monitor profile to Adobe RGB, you will (not "may", but "will") get very wrong color.

Each operating system has a different way to change it, XP, Vista, win7.
if you need help learning how to do this go here:

Oh, I assure you, it is not I who need "help learning".

I keep my monitor ICC color management profile on: Adobe RGB 1998

Here's some "help learning".

1. Get a monitor profiler (EyeOne Display, Spyder, even Huey) and set it up properly.
2. Failing that, see if your monitor vendor has a generic profile for your particular monitor. Wide Gamut monitors typically come with such a profile. It won't be as good as the profile you'd get from an actual hardware calibrator (see 1, above) but it's better than what you're doing.
3. Failing that, download a generic LCD monitor profile for a different brand of monitor, just match the gamut (standard or wide) of your own display.
4. Failing that, disable color management totally: the results will probably look a lot better than your attempt to use a working space as a monitor profile.

On my camera I use: Adobe RGB

Doesn't matter, if you're shooting raw the camera profile is just a tag.

In Photoshop or Light Room I change the Camera Calibrationto: Adobe Standard

In PhotoShop or LightRoom, I shoot the Macbeth ColorChecker or Passport, and generate an Adobe profile with the "Adobe DNG Profile Editor" or with the Passport software. Either is better than the :Adobe Standard" that comes with LightRoom or ACR.

--
Rahon Klavanian 1912-2008.

Armenian genocide survivor, amazing cook, scrabble master, and loving grandmother. You will be missed.

Ciao! Joseph

http://www.swissarmyfork.com

 

[Stephen Christie]

You could be a bit more polite for certain, man get over yourself.

Your typing is very erratic, you said "do .." but I can see you meant to type "do not .."

But I get the idea sort of you mean that if someone uses the wrong things it can result in bad things. but.. You can go on and on about how perfect you think something else is, that doesn’t make doing this wrong.

There is NOTING wrong with the adobe RGB 1998 icc color profile for monitors AND printers, The option is built into windows no need to get anything on the web to set it.
But, why did you say "no Adobe RGB 1998 Color Management Profile exists.." ?

There is nothing wrong with using the Adobe Standard Camera Color Calibration setting on Lightroom or Photoshop either. It's been done by many professionals who see great results since 1998 at least.

There is nothing wrong with setting my camera to Adobe RGB, since I save RAW + JPG, as do many others. Frequently my photos need no PP as result I can just use the JPG file the camera made and skip the RAW stuff.

--
-Steve

 

[Stephen Christie]

You could be a bit more polite for certain, man get over yourself.

You’re wizzing in the wind man.

I don't know what your last post was even about honestly sounded like mad rant not an intelligent conversation.

I thought someone else here said they used a 15% grey card to calibrate from, if I read wrong that’s fine I’m sorry, no need to hate on me. Dam!

I said they NEED to use a 18% card, not a 15%.
Why you saying I “should use a 15% nonexistent card?”
You’re being rude and sarcastic at the same time.

AdobeRGB 1998 Color Management Monitor Profiles certainly do exist and I do use them as many others do and should.

I set ICC Monitor profile to AdobeRGB
Each operating system has a different way to change it, XP, Vista, win7.
if you need help learning how to do this go here:
http://www.microsoft.com/...ddocs/en-us/icm_change_color_profile_monitor.mspx

Yes, as I said use the 18% Grey Card does exist here is one:

http://www.bhphotovideo.com/c/product/375202-REG/Lastolite_LL_LR2050_EZYBalance_Grey_White_Card_.html

I keep my monitor ICC color management profile on: Adobe RGB 1998
On my camera I use: Adobe RGB
In Photoshop or Light Room I change the Camera Calibration to: Adobe Standard

 

[Stephen Christie]

I find it's normal to get yellow skin tones when WB set manyally to 5600K since that is a yellowish which is mix color on the outdoor kelvin scale.

Check out this chart:



http://www.3drender.com/glossary/colortemp.htm

"So, why do we measure the hue of the light as a "temperature"? This was started in the late 1800s, when the British physicist William Kelvin heated a block of carbon. It glowed in the heat, producing a range of different colors at different temperatures. The black cube first produced a dim red light, increasing to a brighter yellow as the temperature went up, and eventually produced a bright blue-white glow at the highest temperatures. In his honor, Color Temperatures are measured in degrees Kelvin, which are a variation on Centigrade degrees. Instead of starting at the temperature water freezes, the Kelvin scale starts at "absolute zero," which is -273 Centigrade. (Subtract 273 from a Kelvin temperature, and you get the equivalent in Centigrade.) However, the color temperatures attributed to different types of lights are correlated based on visible colors matching a standard black body, and are not the actual temperature at which a filament burns."

Thank you Joseph for the detailed answer.

I have another issue that I asked before but nobody could help me.

The problem is that when I use a grey card to correct the white balance, I get a yellow cast. I tried three different grey cards including the color checker and I viewed the pictures on four different monitors. For example when I take a portrait using flash, based on the grey card the color temperature should be around 5600, but I have to use a number between 5000-5200 to get a proper skin tone. I get a very yellow skin tone with the 5600 K.

Thank you in advance.

--
-Steve