Thanks 'thekev' for that thorough response. My referring to the whites were that I had a 2008 iMac24 sitting alongside the new ATD once I had taken it out of the box at home and switched it on for the very first time once connected to my mac mini. I was so shocked at the blue hue and nowhere could I get the screen areas that were white on my iMac, as white on the brand new ATD. In fact the blue hue covered the whole of the screen and when I returned it the very next day I looked at the ATD's on display in the Apple Reseller store and they didn't look much different.
The 'whites' on the new late 2012 iMac sitting alongside in the store were stunning and 'white'. That is what I was expecting from a £800 Display out of the box. Not asking for too much am I ???
No problem man. I try to mention some of the limits of the technology relating to how it's presented, as it can be confusing (calibration sounds like a low level hardware adjustment doesn't it?). Apple has changed characteristics in terms of color temperature settings and other things many times. Even among their current lineup, there's a pretty huge variation. I suspect they want everything to be roughly sRGB, but it hasn't happened. My cmbp notebook screen is actually very cold. Measured natively i1 profiler says roughly 8000K. sRGB is closer to 6500K. Both color temperatures represent a range of colors. I'm talking specifically about the white points, as most displays shift somewhat throughout their ranges.
I will add I've never recommended the thunderbolt display as a display. A lot of people buy it for its functionality as a dock, but there are displays that I like better. I suspect they're going to update it to match the newer imacs soon. I figured June would be an appropriate target initially. My old posted estimate was no earlier than March or April, more likely mid-year. The reason was they wouldn't push a new/expensive process onto peripheral hardware until things stabilized and yields improved. I think you would probably be happier with one once they are updated. Otherwise if you don't mind matte displays and don't require the docking functionality, there are other nice displays on the market.
I am planning to send out my work to a local photo pro shop. I thought I should calibrate my display first. But truthfully... it was the iMac and TBD sitting side by side with mis-matched color profiles that pushed me over the edge to get the colorimeter.
My Spyder arrived today and maybe I'll get around to run a calibration attempt tonight... depending if I get all my work done first.
/Jim
I'm just going to mention a couple things here. The colorimeter helps, but remember that print shops vary, and if you want it to match your display, the color temperature and to a lesser degree the brightness of the light illuminating that print has to match. The image will still look good under other light later, as normally things are viewed in context. Fluorescent lighting is kind of ugly, but if you're at the grocery store, everything you see is lit by it. If it was just one object, the effect would be much more obvious.
Make sure you get a proof either way if you're going to have a large job run. Printing houses still have kind of a draconian way of doing things. I really think the LUT systems used in grading video are much nicer than print workflows.
I think it is typical for various displays to look different... especially when viewed side by side.
There are various programs to help compensate for that, but it's important not to over-correct. Typically matching two displays is kind of a lowest common denominator scenario, and they aren't likely to match on every value. If you're running any kind of profile check that goes through a patch test, you will see many odd colors. They correspond to LAB or XYZ values, which your display matches as closely as possible based on the written profile. I wouldn't expect all of them to match between two, especially those of different models or ages. Typically I would designate a primary display and get the other as close as possible.
I would not try to get a new imac to match a display that has been in service for several years. That would be artificially limiting the imac. I would probably start off with the imac as close to native behavior as possible, so the profile basically just provides your system a better description of the underlying hardware. This is useful for color managed software that needs to make conversions so things will display properly. You can actually demand any set of of target values that the software supports, but that doesn't make it a good idea. After they're both done on native, if the older display is too warm or too magenta or something like that, you can adjust the target settings somewhat. It uses a transformation matrix on pivotal points channel by channel, so overdoing your requests isn't a good thing.
