# Color calibration



## rclanger (Dec 19, 2013)

I hope this is the right section to ask.  I purchased a new monitor to use with the old one. The difference between the two is extraordinarily. I have ordered a "caliber" but am curious about the experience of others.


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## clee01l (Dec 19, 2013)

IMO a calibration tool is essential to accurately view the images and changes to those images.   All monitors will behave differently.  Older monitors will have difficulty producing true colors even when calibrated.  

Color perception from an application works this way  If an application like LR or your browser sends a signal to light up one pixel as "red", it send a number that represents "red"  Once received by the monitor, the monitor sends a number to light up the pixel to show as "red"  It probably won't be the same numeric value. and the color emitted by the pixel may not even be "red" as you see "red"  This is where the calibration tool comes into play.  The software that the tool uses sends a signal for each color and the tool measures the result. It then develops a profile so that the result emitted by the monitor matches or closely matches the color signal sent.  this is the color profile that is used by the OS to adjust the signal sent to the monitor. So that when a "red" is sent, the monitor displays "red".  

There are two type of flat screen monitors available today. Twisted nematic (TN) and In-plane switching (IPS) are the two monitor types.  IPS will be brighter over all even when calibrated.  Further more two calibrated IPS monitors side by side will render with slight differences although less than the difference between TN & IPS


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## Linwood Ferguson (Dec 19, 2013)

What he said, plus to add - some hardware devices will not support independent calibration of two monitors, so you may (or may not) need an additional video card.  On Windows, the calibration is generally done either in the video card LUT table (Look-Up Table), or inside of a hardware LUT in the monitor itself (for example on better NEC's).  When it's done in the video card, some will support independent calibration for two monitors, some will not, and it also depends on which windows you have (I no longer keep track, so not sure on Vista).  

Getting two different monitors to match closely is often tougher than getting them to be "right" since "right" is a bit subjective (as you'll find when it starts asking you what color temperature and color space to calibrate against).  Especially if as Cletus mentions they are different types, but also if significantly different ages.  But it's important to try.  

My personal suggestion is to calibrate  to a relatively dim setting (maximum white point in the 100-150 range; I use 100), and work in a darkened room.  It's usually easier to match monitors if you don't push for "really bright".   I also recommend, if you happen to have bought a "wide gamut" monitor that you NOT use that feature, but rather calibrate it to sRGB as (a) this is far more widely used than wide gamut, and (b) your older monitor is unlikely to be, and  you probably want them done the same.  It's also to some extent "if you have to ask about it you don't want it".   :shock:  

You'll also have to choose a color temperature; again a very subjective choice, but if you want a starting point use D65 (or 6500 - not quite but almost the same thing) as that's close to an average for windows terminals overall.

The real test is whether it matches what you need.  If your goal is to match prints, get a test print with lots of colors made, then you can sit it beside your monitor and compare once calibrated.  Also, just dragging a photo (such as with skin tones) halfway across the windows so it is visible in both is a good way to see how well they match.

But yes, absolutely - for any serious photography use you need to calibrate.

Here's a good general site with lots and lots of color related info, not just calibration: http://www.cambridgeincolour.com/tutorials/monitor-calibration.htm


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## rclanger (Dec 24, 2013)

The calibration equipment arrived. After carefully following the instructions I did see both monitors color change and they are much closer but not identical. The older 19" has more gray. My details follow...











Windows 7 32 all updates are current



GeForce 7600 GT video board
1. LG Electronics E2351
2. AOC TFT 1980


NVIDIA is NOT enabled


Spyder4Express Display Calibration System


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## clee01l (Dec 24, 2013)

The LG is a TN but should be suitable.  The 19" AOC is probably showing its age if gray is the best that you can do.  Knowing that you may want to do your image color adjustments  on the new monitor and use the 19" for less color critical work.


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## rclanger (Dec 25, 2013)

The vendor of the calibration tool I purchased told me it was not designed for two monitors. So I removed the the 19" and will be content with the 23" HD. I think it will work okay. Had I known I would have gotten a larger one. Oh, well.


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## clee01l (Dec 26, 2013)

rclanger said:


> The vendor of the calibration tool I purchased told me it was not designed for two monitors. So I removed the the 19" and will be content with the 23" HD. I think it will work okay. Had I known I would have gotten a larger one. Oh, well.


Calibration of a monitor and actively managing a monitor are in reality two different functions.  You probably can calibrate both monitors separately and assign the generated icc profiles in Vista. Your calibration tool will only actively manage one monitor, adjusting it for changes in ambient room light.


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