What are the RGB values that correctly represent a 5800 K white surface on a calibrated 6500 K monitor?

Question

Consider a high-quality monitor calibrated at the standard parameters: 6500 K, 2.2 gamma, 120 cd/m^2. Calibration is accomplished with a LaCie hardware sensor + its software, and it's quite accurate.

I intend to take a picture of the Sun through a telescope, using a safe, dedicated solar filter (full aperture Baader solar film for telescopes). The Sun's temperature is 5800 K. The filter is "white", quite decent actually, but I'm sure it's spectrum is not 100% flat - rigorously speaking it cannot be. Also, the camera may capture some infrared and so on, and further alter the color of the solar surface.

I want to process the resulting image so that, on the calibrated 6500 K monitor, the Sun's color is represented as close to original as possible. I expect the result to look like a soft creamy white.

Basically, that boils down to representing a 5800 K "white" on a 6500 K monitor. How do I do that?

I could load the image and tweak the tint settings (white balance) in software until the RGB triads on the solar disk fall in the required range, but I don't know what that range is. Sounds like there should be a formula for it somewhere ("given T1 the temperature of the monitor, then T2 white is represented when xR + yG = zB" or something like that, I'm just making stuff up).

Another approach: it would be nice if there was an app that could just generate "white" at any temperature, given that the monitor is calibrated at a certain color temperature. Then I could compare the generated white with the Sun's image, and make adjustments. But I'm now aware of any such app.

Any suggestions?

I do most of my raw file processing in Lightroom, I can use GIMP for additional color channel tricks. I'm not a photography expert, obviously, but I can follow directions. :)

Thanks!

Asked by Florin Andrei

Answer

The answer is: sRGB = (255, 241, 234).

The details of the calculation:

I calculated the spectrum of a blackbody at 5800 K using the Planck’s formula, then multiplied by the CIE color-matching functions of the standard 2 degrees observer and integrated over the wavelengths to get the (X, Y, Z) color. I then divided by X+Y+Z to get the chromaticity:

(x, y) = (0.3260, 0.3354)

multiplying (x, y, 1-x-y) by the XYZ to sRGB matrix, and dividing by the greatest component (R) yields:

(R, G, B) = (1, 0.8794, 0.8267)

I then gamma-encoded, multiplied by 255 and rounded to the nearest integer and got:

(R’, G’, B’) = (255, 241, 234)

Caveat: My answer is in the sRGB color space, which is almost, but not quite 6500 K with 2.2 gamma. BTW, “6500 K with 2.2 gamma” is not a color space specification: you also need the chromaticities of the primaries to get a fully-specified color space.

Answered by Edgar Bonet

Check more discussion of this question.

Why do my sRGB exports from Lightroom look different from RAW files shown in the program even though my monitor can only show sRGB?

Question

I have read tons of docs about color management over the Web, but there is something I can't understand.

I have a screen that can only render the RGB color space.

It is very well calibrated using a LaCie Blue Eye Pro.

I use Lightroom to see an image, shot as RAW with a Canon camera, in "Adobe RGB" color space (even if that does not mean anything in this case).

When I open the image into Lighroom, and export it as JPG in the RGB color space, the image seen into Lightroom is not rendered the same as the one exported.

The thing that I don't understand is that, whatever the color space my original image can be, whatever the screen is calibrated or not, whatever software I use to see the image, if my screen cannot render more than the RGB color space, I guess that the image displayed into Lightroom and the one exported in the RGB color space should be rendered the same way on the screen.

What's wrong ?

Asked by Oliver

Answer

Color management is an annoyance that I've recently been learning about; it is not completely accurate to say that just because your monitor can only display sRGB that it's meaningless for your photos to be edited in the AdobeRGB or ProPhotoRGB space. What is actually happening is that Lightroom is translating colors from ProPhotoRGB into the sRGB space that your monitor can display. It does a bunch of fancy math (I think maybe some matrix algebra? I'm not positive, though, maybe somebody can correct me) to perform this translation -- thus, what you see in Lightroom is not your image as it appears in ProPhotoRGB or in sRGB, you are seeing an interpretation of ProPhotoRGB space in sRGB that tries to be as faithful as possible to what the image would look like on a device capable of displaying ProPhotoRGB.

When you export your photos from LR, you have the option of choosing what color space you want to use for the exported photo (you can choose sRGB, AdobeRGB, and ProPhotoRGB, among others). When LR does this, it first converts the photo into the chosen color space, and embeds information into the JPEG file describing the color space (these things are called ICC profiles). Now, when you open the JPEG in some other program, if that program is able to understand the embedded color space information, it can perform the same math that LR does to convert the file into your monitor's color space, and it should appear the same (or at least similar to) LR. If the program you open it in can interpret this embedded color space information, we say that it's a color-managed application.

The problem is that a lot of applications are not color-managed. Windows Photo Viewer may or may not be (I've read competing statements, but in any case it doesn't seem to work as well as LR); Firefox only supports old versions of ICC profiles, Safari and IE are, and Chrome is not. So if you open up your image in one of those applications that doesn't support color profiles, or doesn't support them well, your image is going to look bad because the proper color translation isn't being performed.

There's a really nice three-part series on color management here. You can also check out whether the device you're displaying supports the appropriate ICC color profiles using this test image. One other really neat feature of Photoshop CS5 (and maybe other editors too, I don't know) is that it will actually show you what parts of your image won't translate color spaces well; if you press Ctrl+Shift+Y, or go to View->Gamut Warning, it will highlight in grey the colors of the open image that don't exist in the target color space. I've found this to be somewhat useful.

Answered by David

Check more discussion of this question.

How do I make my MX880 Canon prints come out in the same colors as on the screen?

Question

I have a Canon MX880 printer which I recently bought. For some reason, prints from Adobe Lightroom come out with bad colors (i.e. not the same as on screen, though not altogether different). I played around with a bunch of setting and couldn't find something to make it work.

Thanks in advance!

Asked by Shwouchk

Answer

For best results you need a "color profile" to match your monitor to the color palette / gamut / system / ... that you are using AND you want a color profile to do the same thing for your printer. Then you see on screen what the image should look like and your printer interprets this correctly. Both are necessary for serious work. If you set printer to screen and the screen is not correctly "profiles" YOU will see good results on screen and printer BUT your electronic images will probably not appear correct to anyone else.

There is more on web about this than you'd want to wade through, but it doesn't take much effort to get a good enough idea for practical purposes.

Some printer manufacturers provide formal profiles for their printers.

Here is an excellent introduction re ICC and ICM profiles and printers -
Understanding Printer Colour Management

Good Introduction to Icc Profiles and Their Use - monitors and printers.

An about.com tutorial - main value is in a number of useful links provided - Calibrate Your Printer

If you have money - Chromix

Adding a co or profile to Windows XP

Wikipedia - color management

Answered by Russell McMahon

Check more discussion of this question.

Can calibrating my laptop monitor remove the need to buy a better monitor?

Question

I have a rather cheap HP laptop. I use it for retouching my photos. I have experienced a huge difference in final colors between this laptop and a Samsung LCD monitor, which I think is better.

To be able to achieve the good results that can be easily seen on many 500px photos (I mean not top notch, but still correct and pleasant):

1. Do I need to calibrate my current HP laptop monitor? The colors and brightness vary quite a bit with little angle variations, so the monitor is not so great ,I think.
2. Can I use a non calibrated better monitor (in that case any price/model example would be great)?
3. Do I need to buy a better monitor and calibrate it?

Asked by Paolo

Answer

Laptop monitors are universally bad with a few exceptions. You likely have a normal low contrast, low gamut, poor viewing angle TN panel. You can calibrate these (I strongly recommend a color meter for this), but there is only so much you can do. At best it will be consistent in color temperature and feel to your desktop monitor.

Calibrating the desktop monitor would allow you a good editing platform. It's not a prograde monitor, but will be consistent in response. If you do corrections to color, contrast, saturation for viewing or printing, it will help prevent unpleasant surprises.

Answered by theatrus

Check more discussion of this question.

Color correction and calibrated monitor

Question

I have a rather cheap HP laptop. I use it for retouching my photos. I have experienced a huge difference in final colors between this laptop and a Samsung LCD monitor, which I think is better.

To be able to achieve the good results that can be easily seen on many 500px photos (I mean not top notch, but still correct and pleasant):

1. Do I need to calibrate my current HP laptop monitor? The colors and brightness vary quite a bit with little angle variations, so the monitor is not so great ,I think.
2. Can I use a non calibrated better monitor (in that case any price/model example would be great)?
3. Do I need to buy a better monitor and calibrate it?

Asked by Paolo

Answer

Laptop monitors are universally bad with a few exceptions. You likely have a normal low contrast, low gamut, poor viewing angle TN panel. You can calibrate these (I strongly recommend a color meter for this), but there is only so much you can do. At best it will be consistent in color temperature and feel to your desktop monitor.

Calibrating the desktop monitor would allow you a good editing platform. It's not a prograde monitor, but will be consistent in response. If you do corrections to color, contrast, saturation for viewing or printing, it will help prevent unpleasant surprises.

Answered by theatrus

Check more discussion of this question.

How do I calibrate two different monitors to the same whitepoint?

Question

A few days ago I invested in an X-Rite i1 Display 2 colourometer, as per this answer, although I'm having great difficulty getting a Dell U2412M and a Dell E1911 monitor to the same whitepoint. I've tried the software that the device came with and a demo of another piece of software (I can't recall the name unfortunately). I have settled on a piece of free software called Argyll CMS along with the GUI frontend dispcalGUI, as it seems a little more capable; however, this is simply my impression of it.

I'm aware that there will be differences in quality between the U2412M and the E1911, although I'd have thought that after calibrating the monitor and creating a high quality profile for both monitors that the difference would be next to impossible to detect with the eyes. However, there is a very noticable difference in the colours the two monitors show. The U2412M seems to have a slight red tinge to it, while the E1911 has seems more of a grey tinge.

The calibration settings I've used for both monitors is as follows:

Whitepoint: 6500K
White level: 120cd/m2
Black level: Native
Tone curve: 2.2
Calibration quality: High
Profile quality: High
Profile type: Curves + matrix
Testchart file: Large testchart for "curves + matrix" profiles.

I have control of the brightness, contrast and individual RGB channels, so I'm able to calibrate the monitor before using a profile. I've put up links to the profile verification reports for the U2412M and the E1911. You can see that each monitor seems to struggle with particularly blue colours.

Obviously there is no way you can see the actual colours displayed by the monitors, but as I said, it is quite a noticable difference. I know this is a little open-ended, but could anybody suggest what may be going wrong here, or have I just got bad quality monitors?

Asked by R4D4

Answer

I used to work for Gretag MacBeth (and later X-Rite when they acquired Gretag.) I've written code for color monitor calibration. Your calibrator is defective and it should not do that. Sadly, the color filters in the unit itself may not ever be able to calibrate your monitor. My i1Display will not calibrate my MacBook monitor... I would contact X-Rite and see if they'll take it back or replace it.

The X-Rite ColorMunki was in development when I left there. It may be a better choice but if I recall it is pretty expensive.

Answered by Paul Cezanne

Check more discussion of this question.

Wouldn't it be better to calibrate the RGB settings of my monitor instead of using ICC profiles?

Question

I've got three monitors, a Dell Ultrasharp U2412M and two Dell E1911 19" monitors, although the E1911 monitors look pretty terrible for colour so I'm desperately needing to calibrate them.

I've done a little bit of reading and it seems that I use a piece of hardware like the Eye One Display 2 and then some packaged software to create an ICC profile for that particular display, but it seems though that the ICC profile is ignored for certain things (PC gaming etc.).

The monitors all allow adjustment of the brightness, contrast and individual RGB channels; it would seem that setting the monitors RGB channels would be superior than using an ICC profile, but I'm struggling to find software that is capable of profiling the monitor and then telling me the ideal monitor settings without using a profile.

Also, is there actually a difference between the Eye One Display 2, which sells for £130 and something like the Spyder3Express which is £85, or even cheaper ones like the Pantone Huey PRO? The reviews for these devices seem to focus more on the packaged software. I'm aware that some software can't handle multi-monitors, this isn't an issue though as unplugging a monitor isn't a great deal.

Asked by R4D4

Answer

A hardware calibrator like the Eye One Display 2 will go through two steps: calibration and profiling.

• Calibration is where you will make adjustments to the display with the monitor's controls -- you'll use the brightness, contrast and individual channel controls, as you noted. This is the gross adjustment step, and obviously gets the display into good shape.

• Profiling is basically the process of building the ICC profile you mention. Profiling is looking for little details that need adjustment. This is the fine adjustment step, adjusting for a slight cast here or there.

It's been years since I've looked at what the hardware calibrators were capable of so you might take this with a grain of salt, but my experience was that the Eye One Display 2 (which I have) was leaps and bounds better than the ColorVision Spyder products.

Answered by Dan Wolfgang

Check more discussion of this question.

My pictures are never printed. Is there any point in buying a better monitor?

Question

My monitor is pretty cheap and its colours are horribly dependent on the viewing angle, the moon and whatnot. I could edit my pictures on my old CRT, but its contrast and sharpness are quite bad.

On the other hand, I never print my images anyway but only publish them on the web. Thus, the important thing is actually what they look like on other people's (non-photographer's) monitors.

In this case, is there any point in spending money on a better monitor or even a calibration set?

Asked by user1080125

Answer

Yes, there is a point. It will let you see your own photos more accurately. Since you do not print them, I assume you look at them on your own monitor.

Even if it is only for others, non-calibrated monitors differ widely but they are improving at least in the mid-range with the advent of LEDs (and eventually OLEDs), so over time people will see your images more accurately. Having a good monitor will let you know better how you images will appear to others too then.

Calibration goes a step further and is highly recommended if you manipulate your images since it will let you see the effect of your changes. Otherwise you can introduce very unnatural looking colors.

If you have to choose one though, I'd go for a better monitor. You can always add calibration later. Finally, if you do not require a huge display size, great color-calibratable monitors are no longer than expensive. I always recommend the NEC P221W even though I don't work for NEC ;) but I spent years evaluating LCD displays professionally. I bought two of those refurbished for $237 each while they go for $450 new. There is also a 24" version, the P241W.

Answered by Itai

Check more discussion of this question.

Why don't you need to calibrate a camera's LCD screen?

Question

I saw this question from Leon Neal on Twitter a while back:

If a computer screen needs constant calibration and checks, how come the screens on our cameras lack that facility?

I can think of a few potential answers but I'm not sure any of them completely cover it:

1. Because it's too small to be used for fully accurate work anyway (so near enough is good enough).
2. Because it's only for previewing, not for editing.
3. Because it's not usually the last screen we view a photo on: it's normally going to be copied onto a computer so colour management can be left until later.

However if you think of a press photographer at a news event, perhaps shooting JPEG for speed and filing the pictures over the air straight from the camera to a news desk, then none of those reasons really hold water. Surely they have a valid need to check that the camera's colour reproduction is faithful?

So: is it in fact possible to calibrate a camera's LCD? If so, why do so few of us bother? And if not, why not?

Answer

Two words: "ambient" and "context".

At the risk of making what sounds like a "No true Scotsman" argument, "real" monitor calibration is always in the context of the ambient lighting conditions. Not only do the pertinent standards (ISO 12647 and related) specify the lighting levels and colour temperatures under which critical colour work should be performed, pro-level calibration devices sample the ambient light as well as what's coming from the monitor. Since both the actual value of the max black and the apparent value of the max white depend on the ambient lighting, you can't really make even the basic global contrast adjustment without regard to ambient. (And if you are calibrating your monitor under one set of lighting conditions and using it under another, you're fooling yourself -- you're not really doing that much better than an educated eyeball calibration would have gotten you.)

In terms of actual calibration, then, you would pretty much need to do a fresh calibration every time you look at the LCD (or, at least, for every shooting session). And you'd have to hold the camera at the same angle under the same lighting every time you used that profile (or get used to using a sealed viewing environment, like a HoodLoupe or a dark cloth/viewing tent). If you have time to be messing about like that, you're probably not shooting breaking news or sports action.

Recent cameras will allow you to do an educated eyeball calibration, at least within the limits of the device. All you need is a reference image on the card. But unless the screen is way out of whack, I'm not convinced of the utility of anything other than the basic brightness setting (which is a contrast setting in the context of ambient lighting). If you can count the number of mireds you are off by on one hand, you won't be able to tell the difference without an external reference anyway, and I don't recall running across any cameras that allow you to manually adjust gamma conversion curves and so on in-camera (although many of the better ones will let you create your own presets externally and import them to the camera).

We have ways of calibrating the capture instead, which is of far greater utility. That includes things like setting a white balance (auto, camera presets, or custom, all with fine tuning for preferred deviations like warmth), including calibration targets (from a simple grey card to more comprehensive targets like a ColorChecker or SpyderCube) in images, global and channel histograms and blinkies (highlight warnings). And if the colours really are that critical (say for advertisement product photography), you're almost always going to be using a "colour to target" tool in post to match a Pantone specification anyway.

Check more discussion of this question.

How can I maintain photo color consistency across computer monitors?

Question

When saving photos for the web from within Photoshop I run into issue where my colors are not consistent between monitors. While I understand there will be some difference between monitors there are at times a huge difference between my desktop monitor and my laptop monitor. In the best cases the colors (on my laptop monitor) are a bit washed out but not to bad in worst cases the colors are completely different shades and the picture is not blown out but close. If I adjust the colors on my desktop monitor to compensate for my laptop monitor the colors (majority of the time) are way to dark. Are there any tips/tricks on maintaining consistency across monitors?

A few notes: I always save my photos for web using Photoshop's Save for Web and Devices below is a screenshot of my settings. (I have un-checked Embed Color Profile would that help?) I have calibrated both monitors as best as possible with software. (I am not using any form of hardware calibration.) And the monitor for my desktop is an old LCD monitor. (It is at least 6 years old but was not in use for at least 2-3 years of that 6.) The laptop is a new computer. (Is age going to be playing into this issue?) And finally neither monitor is a "Glossy" monitor.

Answer

I think the basic answer here is: you need to get a hardware-based calibration device and use that on both monitors. As you have experienced, it's really hard to get this right by eye. Getting the monitors calibrated correctly will help, but if one or both of them are really poor equipment, you still may have limitations.

You're already saving the image in the limited and "safe" sRGB color space, so there's really very little more you can do to the image itself.

Check more discussion of this question.

Why doesn't Aperture show black as black?

Question

Aperture seems to be displaying my images brighter than they actually are -- this makes colors seem washed out and makes it very difficult to accurately adjust the black point and other exposure parameters.

Here's a screenshot:

Notice that the loupe (set to the same magnification as the zoomed-in image) is more saturated, and blacks are blacker than the surrounding image.

Also compare the bottom edge of the image to the black strip just below it.

This happens even for totally black images, and is independent of any image adjustments:

Why is Aperture messing with my colors like this? How can I fix it?

Answer

You've accidentally turned on Onscreen Proofing, which is used to simulate the colors of a final output medium like CMYK ink on paper. Turn it off by going to the View menu and clicking Onscreen Proofing, or hitting Option-Shift-P

Check more discussion of this question.

How to Calibrate a Monitor Without Hardware

Question

The question:

What is the best way to calibrate my monitor without hardware add-ons (and preferably free)?

Some More Info:

From what I have read what seems like the best way to calibrate my monitor is using a piece of hardware like a Spyder or something similar. Yet currently while it is on my list to buy it will not be an immediate purchase.

So it comes down to this, what is the best way to calibrate a monitor using software/my eyes. Also I understand this is not the best, however, my theory is that this is better than nothing at all.

Answer

There are software options to do this, either free or in your OS. They're not as ideal as a hardware solution and are a bit more fussy to complete, but they're a little better than not doing it at all.

For Windows: Quick Gamma

For Apple OS X: ColorSync

For Linux: A utility called "Monica" but all the current download options are a bust, so you'd have to hope you can find it in your distro.

Check more discussion of this question.

How does a display calibration device like the Spyder 3 work?

Question

I was looking up information about monitor calibration and came across the Spyder 3 Express, Pro, and Elite.

How does the Spyder 3 work to calibrate your monitor correctly?

Answer

These hardware calibration devices work by running a piece of software on the computer that displays a series of colors and grey levels. By placing the spyder reading device on the computer monitor, it is able to "see" what the computer is displaying. By taking a series of measurements, a profile of the total system including video drivers and monitor quirks can be assessed. Once this profile is built, it is usually loaded into the OS so that the monitor then displays calibrated image colors.

The differences between the product line usually covers how many monitors can be calibrated for each computer to accommodate multi-screen setups.

Check more discussion of this question.

Why do my photos look better on an iMac?

Question

I've been given a long term loan of a 27" iMac. Looking at my photos on flickr and iphoto, they look, eh, just better, they seem to pop more than they did on the other PCs. Why is that? The other computers I am used to using are a dell desktop with LCD and low end dell laptop.

Answer

The 27" LED mac displays are "full gamut" displays, ones that cover around 98% of the Adobe RGB gamut. These are full 8 bit/channel (24bit) screens and offer a full 178° viewing angle. They are much higher quality displays than your average LCD screen, and specifically designed to output high quality, rich, saturated graphics. Additionally, Safari, which I assume you are using on the Mac, supports ICM. Browsers that support ICM will generally render photos with more accurate color than browsers that do not when an ICM profile is present in an image.

Your Dell computers are probably using much cheaper, 6 bit/channel (18bit) or 5/6/5bit (16bit) screens, and are likely not LED LCD screens but standard CCFL LCD screens. While these screens generally have higher refresh rates, and are great for gaming and movies, they do not reproduce color as accurately as diplays with higher bit depth and wider viewing angle. Contrast and color rendition on the cheaper Dell screens will generally cover the full sRGB gamut, but will fall quite short of the much richer and more saturated Adobe RGB gamut.

The Apple screens are middle ground, though. They use standard yellow phosphor/blue LED backlighting, which over the long term will often result in non-uniform color shift as the LED's age. CCFL backlit screens are less likely to encounter such color drift over the long term. For LED screens, full RGB LED will produce much cleaner, more consistent results over the long term. High end RGB LED screens designed for photo and graphics editing work will render the richest color (sometimes covering as much as 123% of the Adobe RGB gamut for maximum saturation) and purest white (blending RGB to form white more accurate than converting blue LED light into white light via a yellow phosphor, and is less subject to color drift over the long term.)

Check more discussion of this question.

How to apply color management to the Windows 7 mouse cursor?

Question

I have been using the Sypder 3 colorimiter and Datacolor Spyder3Elite software to calibrate my screen for several years now. The Sypder3 does wonders, and really improves the quality of my on-screen color representation.

There is one little annoyance, however, and I am curious if anyone else has encountered this. I calibrate my screen to a D50 white point (5000k), as it more closely matches the fine art papers I most often print on. The windows mouse cursor, however, is a very stark, bright white with a tinge of blue (7300k or so), like a glossy photo paper with copious amounts of optical brightener. I'm a little confused as to why my mouse cursor doesn't follow the white point of my monitor's color profile.

Has anyone else encountered this? Is there a way to fix it?

OS: Windows 7 Ultimate

Answer

Yes, I have a Spyder 2, and I experience the same on all screens that I have calibrated, although not as strongly as you as I calibrate to 6500K. As the mouse cursor is drawn using a hardware sprite rather than drawn as regular graphics, if the graphics hardware supports it, it's not affected by the color profile.

You might consider changing the color temperature of the monitor closer to 5000K before calibrating, if it supports it. That would make the cursor stand out less, and it would also result in a color profile that makes better use of the dynamic range of the monitor.

Check more discussion of this question.

How do I software-calibrate my IPS monitor under Mac OS X?

Question

I just purchased a HP ZR24W after reading several reviews for IPS monitors. I am a novice photographer and have never done any monitor calibration or owned an IPS panel before. I have a 2009 13 inch Macbook Pro with OSX Snow Leopard running on it.

I hooked the monitor up to the Macbook and thankfully even though the HP CD did not have any OSX drivers the monitor was set up correctly with the correct resolution. I have to say the default setting was pretty good for image viewing. But I guess to get the best out of the monitor I need to make some changes.

Hardware calibration seems the obvious option but I have spent all of my budget on this monitor and can't get one in the near future. So, I'm stuck with software and manual calibration.

Can anyone help me as to how to do this via software or changing the various controls manually in the monitor? Any tutorial or best practices would help me immensely.

Answer

First I want to make sure that the importance of proper hardware calibration is understood. Your eyes are not perfect(mine especially) and you can certainly give it a shot to determine the best brightness, tint, gamma, etc. but you are not going to be nearly as spot on as a dedicated piece of hardware. In reading you will find that as the display gets older, it becomes more out of sync with the correct values, and hardware calibration becomes more important. So even if you can't afford it now, down the road it is still a good investment.

So onwards to how to actually do a visual calibration. You are in luck, because OS X actually has a utility built in to do exactly what you want - Display Calibrator Assistant. To find this utility all you have to do is open up System Preferences, then the Displays app, click on the Colors Tab, and you will see an option for Calibrate. From that option, make sure you are in expert mode, follow the instructions, and you are on your way to visual monitor calibration bliss.

Other options exist that are not included with OS X. You may even receive one with your monitor as part of its software package. A popular option is a shareware program SuperCal.

If you are looking for a tutorial on how to use the built in Calibrate tool from Apple you can find that here.

Check more discussion of this question.

Why are my photos slightly yellower than they should be on iPad 1st gen?

Question

I just transferred some photos from my Macbook to my iPod Touch and my iPad 1st gen. I found that photos on my iPad are a tad warmer than they are on my Macbook and my iPod Touch. Has anyone experienced this before?

Answer

Different displays ship with manufacturing tolerances which will give each unit fractionally differing colour output; in addition to this, manufacturers may choose to ship with factory default colour settings. To complicate matters further, the capacitive covering over the iPad screen may introduce a colour cast of its own.

The only way to get reliable colour reproduction is to use a colourimeter to calibrate the screen, although this obviously won't be possible for the iPad half of your situation.

Check more discussion of this question.