# iMac Calibration



## myko5 (Aug 13, 2012)

I just got an iMac delivered today and I have only had a few minutes to really get it hooked up and mess around on it. I am very new to apple for the exception if the iPhone. Anyways, I came across the monitor calibration on the display menu. How good is this calibrator in relation to one you would buy at a store like the spyder or x-rite's I think they are called. 

It does have settings for Adobe RGB which I believe what my camera is set to. So would that be wise to choose, or try the custom calibration?
Just curious. 

Thanks


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## jamesbjenkins (Aug 13, 2012)

Compared to a lot of other displays, the stock iMac display is actually really good. It's the same high quality IPS display at the Cinema Display.

That said, there's no stock utility that can tell you anything about the ambient light in whatever room your computer is. The light hitting the display has just as much to do with calibration as the pixels themselves.

Hardware calibrators like the iDisplay 2 Pro and the Spyder can measure the color temp and intensity of your room's ambient light, and then incorporate that data into the color profile (.icc file) it creates for you.

Hope that helps.


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## jamesbjenkins (Aug 13, 2012)

PS.

You should probably set your camera to sRGB instead of Adobe RGB. Unless you manually convert in Photoshop, Adobe RGB will display really dull, flat colors when displayed on the web or in print (generally speaking).


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## myko5 (Aug 13, 2012)

Doesn't adobe rgb have a wider range of colors though? If so, wouldn't that create a more colorful and less flat and dull color for web and print???


As far as the iMac's display right out of the box, it is definitely amazing. I just didn't know how accurate it was and if getting a calibration software right away was necessary. I realize my colors have been of in my photos due to my crappy laptop display.


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## KmH (Aug 14, 2012)

The web (most electronic displays) can't display the color gamut that is encompassed by Adobe RGB. 

Most print labs want image files in the sRGB colorspace. any print lab that can handle Adobe RGB will usually say so somewhere on their web site.

Tutorials on Color Management & Printing


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## myko5 (Aug 14, 2012)

Great, good to know. Thanks Keith.


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## KmH (Aug 14, 2012)

Many image editing experts recommend editing in the largest color space available to you, and then converting to the colorspace required for the images use.

In Photoshop that would be ProPhoto RGB. The ProPhoto RGB color space is so large it encompasses colors humans cannot see.

Lightroom also uses a wide gamut color space almost as large as ProPhoto RGB- Melissa RGB. The difference is ProPhoto RGB uses a gamma of 1.8, while Melissa RGB uses an effective gamma of 2.2.


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## myko5 (Aug 15, 2012)

So if I should be editing in the largest color space available to me, shouldn't I be taking pictures in the largest color space available from my camera? Essentially anything that I am going to want to keep or print, I am going to be editing in photoshop. So would it be recommended that I just start off with a better color space to begin with? 

So in summary, I should leave my camera in Adobe RGB. Open in photoshop or lightroom (both or which I still have to buy) with ProPhoto RGB? Then convert it back to say sRGB unless the print lab can handle Adobe RGB?

Sound right?

Sorry if this is all in the link you provided Keith, I have not had the chance to view it.


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## KmH (Aug 15, 2012)

I regret wasting my time with the link then. I thought you wanted to understand this stuff.

The color space setting in your D90 is only applied to JPEG files.

If you shoot Raw, the color space setting is essentially meaningless.

If you're shooting JPEG, Fine, Large, about 80% of the image color data is discarded in the conversion to JPEG (usually a 4:1 reduction in the file size of the original Raw image data file). In addition the image pixels are grouped into Minimum Coded Units (MCU's), which are 8x8 pixel, 8x16 pixel, or 16x16 pixel blocks that represent the smallest subsequent editable units.

That's why JPEG is called a *lossy* compression method. http://en.wikipedia.org/wiki/Jpeg


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## myko5 (Aug 15, 2012)

All the more reason to keep shooting RAW.


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## Ysarex (Aug 15, 2012)

myko5 said:


> Doesn't adobe rgb have a wider range of colors  though? If so, wouldn't that create a more colorful and less flat and  dull color for web and print???
> 
> 
> As far as the iMac's display right out of the box, it is definitely  amazing. I just didn't know how accurate it was and if getting a  calibration software right away was necessary. I realize my colors have  been of in my photos due to my crappy laptop display.



The problem with web display isn't about how wide the color gamut is.  The problem is in how the color information is decoded for display. RGB  color values are undefined without a colorspace reference. So this is  not a specific color: R = 175, G = 35, B = 90. Those are meaningless  numbers. For those numbers to identify a color in an RGB photo they must  reference a colorspace. Some web browsers and other software (including  photo-specific software) do not read and decode the colorspace tag (ICC  profile) embedded in a photo. Here's those numbers noted above and the  color they define:







In another colorspace those numbers define yet a different color.

Here's a simulation of approx. what happens when an Adobe RGB photo is displayed without decoding the ICC tag. The bottom version of the colorchecker shows the distortion.

View attachment 17026

You're using a MAC and so likely using Safari as a web browser. Safari  correctly processes the colorspace tag and so photos would be properly  displayed. The web problem is with browsers like Chrome and IE.

Printing is another matter. Unless you're using a high-end inkjet  printer of the 8 to 12 color variety Adobe RGB isn't going to do much  for you. It does little good to specify a color in your photo that can't  be physically produced by the printer. For that matter you may also  want to consider that colors in the Adobe RGB space can't be physically  displayed by your iMAC either.

Joe


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## 2WheelPhoto (Aug 15, 2012)

myko5 said:


> All the more reason to keep shooting RAW.




+1 indeed


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