iMac screen replaced - calibration color horror

[The View]

My 24" white iMac's screen got replaced.

When I started it up, all colors looked as they were before.

Great.

But I did a calibration anyway.

The new profile was a horror. Yellow.

The weirdest thing was, that when calibrating it with i1D2, the screen brightness went down to 103 cd2. The 24" iMac cannot get this low with brightness.

The old screen got to 140cd,  and not a tat below. And the new screen just looks as bright as the old one.

I ran the diagnostic software, and my i1d2 passed.


I really don't know what is going on here. I set the screen profile back to the old profile, as the new one has to be wrong. (When images come out of Canon DPP, they look good. With the new calibration they are yellow as hell).

[teddillard]

My 24" white iMac's screen got replaced.

When I started it up, all colors looked as they were before.

Great.

But I did a calibration anyway.

The new profile was a horror. Yellow.

The weirdest thing was, that when calibrating it with i1D2, the screen brightness went down to 103 cd2. The 24" iMac cannot get this low with brightness.

The old screen got to 140cd,  and not a tat below. And the new screen just looks as bright as the old one.

I ran the diagnostic software, and my i1d2 passed.
I really don't know what is going on here. I set the screen profile back to the old profile, as the new one has to be wrong. (When images come out of Canon DPP, they look good. With the new calibration they are yellow as hell).
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A couple quick questions...  What model iMac is this (old white or new thin version?), and what was the issue that caused the replacement?

[The View]

Hi, Ted.

It's the white model with the 2.1 ghz Intel Core 2 Duo and 3Gb RAM. 7600gt video card with 256mb vram.

Old screen had a slight light fall-off to the right, not really a lot, but enough to make side by side-comparisons of images impossible.

What really stuns me most are the brightness readouts when working with the Eye One. I mean, the brightness looks exactly the same as the other screen, and the measurements are way down. To reach 120 cd2 I need to brighten the screen up to the fourth bar (pressing f15).

[teddillard]

Damn, we're stumped.  

One trick to try is the old "User Account" ploy.  Make a new user, log in, do the profiling, and see if it does the same thing.  If that fixes the problem then there is some issue with the account you are normally using.  

I keep thinking it has to be something along those lines.  Maybe even try a reinstall of i1, and clear out the old profiles.  

You can also reset the PRAM.  Restart holding down Command, Option P, R.   All four.  Wait for it to chime, It will chime over and over as long as you hold those 4 keys down.  I usuall do it at least 3 times.  That's what they do when they don't know what else to do, and sometimes it even works.  At least it's easy and doesn't do any harm.  Give that a try.
 
Our techs say to take it back, because it worked before the replacement...  but they're like that.  

sorry I don't have more for you.

[The View]

Thanks, Ted, for the hints.

Fixing misbehaving computers is difficult enough when you can get a hand on it, so I was just hoping for a few hints from remote locations.

I wasn't expecting the "did you try to click 'make a correct profile' button magic thing

I'll attack the problem again this evening. It's a little bit like a black box: you don't really know what's on a computers'  mind... so you try this and that.

[teddillard]

Thanks, Ted, for the hints.

Fixing misbehaving computers is difficult enough when you can get a hand on it, so I was just hoping for a few hints from remote locations.

I wasn't expecting the "did you try to click 'make a correct profile' button magic thing

I'll attack the problem again this evening. It's a little bit like a black box: you don't really know what's on a computers'  mind... so you try this and that.
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heh... ain't that the truth.  Please do let me know if you're able to solve it, this kind of thing drives me nuts.

[The View]

I guess I found the problem.

Very likely the old screen had serious issues and calibrated wrong. I don't know if this is technically possible, but, for now, that's my explanation.

(how do I know that? The new screen looked exactly the same like the old one with the old calibration/profile. Only the new profile was very, very different).

The new calibration showed a yellow cast in DPP's conversions.

It turned out that they are indeed quite yellow, but for some reason, the old, wrong calibration with the old monitor gave the images a more pleasing appearance (by actually having a red cast, which is not as ugly for people like a yellow cast) out of the box than the new, right calibration.

I will need to create a new preset (picture style in DPP's language), that gives a more balanced appearance upon import.

Key will be test prints I'm going to do soon.

But as the colors of DPP and their import into Photoshop CS3 match for the first time really well, I seem to be on the right path.

The fact that the new screen dims down to under 120cd2 still puzzles me. (It's my third screen on this iMac. The first had a faulty inverter board and hummed, the second had uneven lighting - right side darker than the left,  and, as it shows, equally unreliable colors - if that's technically possible for an LCD screen to be impossible to calibrate).

The new screen could be a panel from a later production and maybe this is the reason why it dims down more. I have done lots of warm-up, and still, the lower brightness stays. Maybe I got lucky this time and got a really good screen. Test prints will show.


PS: I threw out the preferences files for DPP, which didn't change a bit.

I guess this was kind of a two pipe problem, Sherlock Holmes-wise, who was lucky enough to never have to investigate color management problems.