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Veltliner · Sep 8, 2008, 02:09 AM

Today I got my 24" iMac (2.1 Ghz white) replaced.

The old one had a difference in brightness between the left and the right side.

I calibrated the new screen. And shock! Everything looked totally different.

When I load the old screen's profile, the colors are back to normal.

Also: the new screen goes down to 106 cd2, while the old one barely got under 140 cd2.

What does that tell me? Did I get a dud? Why is it so much dimmer - says the calibration software, but to my eyes the brightness is pretty much the same. If I use the old monitor profile, everything looks just the same as before.

Logic would say, that my calibrator is bad. But I used i1 diagnostics, and it says it is fine.

Could it be that there is something wrong with my new screen that makes it impossible to get calibrated.

Or could it be that my old screen was so bad, that all the colors were wrong?

Why gives the new one such dim measurements?

solofx7 · Sep 8, 2008, 12:01 PM

what calibration software...

lenox · Sep 8, 2008, 12:55 PM

Calibrate it with your eyes and the apple calibration utility (advanced mode).

Veltliner · Sep 8, 2008, 03:50 PM

Calibrating with Eye One Display Two.

Passed the exam with iDiagnostics software.

What is really strange is the brightness read-out of the Eye One. I mean, 106 cd2, no 24" iMac can go that low. 140 on the lowest setting is normal. To reach 120cd2 I have to go to the fourth bar in the brightness setting.

The thing is, that its brightness looks exactly the same as the old screen. The screen looks totally OK, and I know the person, who installed it, is a very capable technician who would not mess it up. He also ran all the screen hardware tests.

imitchellg5 · Sep 8, 2008, 05:20 PM

No two displays are the same. Nowadays they are pretty similar across the board, but there can still be differences. Just look at (especially the 20") iMacs in the Apple Store. You'll notice varied levels of brightness even if they are calibrated the same.

Veltliner · Sep 8, 2008, 06:16 PM

Given that, I'm kind of trained to see very minor differences of brightness and lightness. Otherwise I couldn't edit images.

And this screen is not darker than the other one.

And especially as the profile for the old screen fits perfectly. If I didn't know the screen was replaced I wouldn't notice working with the old profile.

I'm going to work on it again this evening. Hopefully something shows up that I can put my finger on for causing this.

Eug · Sep 9, 2008, 10:59 PM

Originally Posted by imitchellg5

No two displays are the same.

Not only that, they actually use different models, or different revisions of the same model at least.

tooki · Sep 12, 2008, 04:57 PM

Did you let the new LCD warm up for at least 30 minutes before calibrating? The backlight fluorescent tubes don't reach full brightness immediately, so if you calibrate right after turning on or waking from sleep, it is going to be dimmer!

imitchellg5 · Sep 12, 2008, 05:23 PM

Originally Posted by Eug

Not only that, they actually use different models, or different revisions of the same model at least.

Very true. The new panel could be a totally different model or even brand (most of the time they are Samsung panels I believe).

Veltliner · Sep 13, 2008, 05:39 PM

Originally Posted by tooki

Did you let the new LCD warm up for at least 30 minutes before calibrating? The backlight fluorescent tubes don't reach full brightness immediately, so if you calibrate right after turning on or waking from sleep, it is going to be dimmer!

Yes, I always do that.

The new display still dims down more.

Next thing I'm going to check all the preferences files that have to do with color management.

Veltliner · Sep 13, 2008, 05:41 PM

Originally Posted by imitchellg5

Very true. The new panel could be a totally different model or even brand (most of the time they are Samsung panels I believe).

Well, I hope they don't give out cheaper versions for replacement.

(Doesn't look like it. It actually looks like to be a very good panel).

Dimming down a display is necessary anyway for photo editing. You can't edit on 200cd2. So, all will come down to what happens when I get hold of all the color settings in my editing applications.

Veltliner · Oct 3, 2008, 10:26 PM

I just found out that the new panel also overdoes the highlights on the left side of the screen.

I juts wonder if this is due to the construction of the white 24" iMac...

Maybe you need to have high end equipment for really evenly distributed brightness.

kerisabe · Oct 7, 2008, 12:17 AM

well i just got my iMac 24" 3.06ghz and sold my 17" mbp, im kindda pissed at first on how bad the screen is! I didnt even notice anything at the apple store. the brightness on the left side of the screen is more than the right. And the monitor is too bright, the lowest it goes is 220cd/m2 says my spyder 3.

I've figured out a solution to the "too bright" display. I do alot of photography work on this computer, and correct profile/monitor calibration is very important to me. So here goes..

I downloaded the program called SHADES, COLOR EYES DISPLAY PRO, and of course you have to have any calibration tool that works with the COLOR EYES DISPLAY PRO software. Why COLOR EYES DISPLAY PRO? Cause the software supports calibrating Apple monitors. First, Turn on SHADES, set Shades to display 0% as your lowest brightness, and then set it at 65%. Then hook up your calibration tool, turn down the Backlight on your iMac to the lowest, open CEDP software, set up the gamma to 2.2, D65, luminance 105 cd/m2, and make sure you cover the screen just to make sure there is no light reflecting on the screen. It should work.

Now the screen imo is pretty nicely calibrated the only thing is the bright left side, other than that it's good now. So good luck..

Veltliner · Oct 8, 2008, 12:20 AM

Actually, I have an older (white) model with a matte screen which are supposed to be better.

(Actually, my new, replaced screen dims down to 205 cd2, according to my i1d2)

The problem is the unevenness of light.

This particularly concerns highlights. I was working on a portrait, and it chanced its character simply by moving the image to the right side of the screen, and then to the left (the reflections on the skin, which is a very important moment in forming a portrait).

I'll do some more research, but I have the impression that a really, really evenly lit screen is way more expensive than what is possible to put into an iMac at this price.

The screen, not to misunderstand me, is gorgeous! Wonderful colors! Sharp!

It's just not regularly lit, which puts anybody doing critical image work at a risk. (I hope, that at least the colors will not shift too much from the center).

As for now, I'll stay in the center of the screen.

And side by side image comparisons (of which I'm much less dependent now than only a year ago) will have to focus on the little area in the center of the screen.

kerisabe · Oct 8, 2008, 02:43 AM

forget about what I said above! shades is actually incaccurate.

Finally ive got my eizo CG241W screen, now I use the calibrated profile from the Eizo Screen combined with Gamma control, the iMac dimmed down. Now the backlight set at max, adjust using gamma, it looks identical to the eizo. eventhough it sucks still lol. Should be at 120cd/m2. Anyways, im getting the iMac screen checked tomorrow since it's defected. Hopefully they let me exchange to a mac pro. fingers crossed. Im loving the new EIzo screen btw the best 2500 ive ever spent!

Veltliner · Oct 11, 2008, 12:50 AM

Originally Posted by kerisabe

forget about what I said above! shades is actually incaccurate.

Finally ive got my eizo CG241W screen, now I use the calibrated profile from the Eizo Screen combined with Gamma control, the iMac dimmed down. Now the backlight set at max, adjust using gamma, it looks identical to the eizo. eventhough it sucks still lol. Should be at 120cd/m2. Anyways, im getting the iMac screen checked tomorrow since it's defected. Hopefully they let me exchange to a mac pro. fingers crossed. Im loving the new EIzo screen btw the best 2500 ive ever spent!

Congratulations to that great monitor.

For me, that's also all the way up on my list.

I'm getting more and more frustrated with my 24" iMac screen - and I have the matte display. Left side is ALWAYS BRIGHTER, and the colors are definitely off.

With critical images I change positions for two images on comparison, but the left one always looks better when they are pretty close.

Unfortunately, I have to say for color critical work NO iMac is suitable due to the way the screen is backlighted.

For those facing the decision: put your money into the screen, and get the cheapest computer that does the job. If I can't come up with the money for the MacPro (they are still so horribly expensive) I'll probably get a mini plus an Eizo ColorEdge. May be slower, but at least I get the right colors and luminance levels.

kerisabe · Oct 11, 2008, 04:38 AM

Got the iMac checked 2 days ago, they said the screen is defected so they offered me to fix my iMac since it's passed the 14 days refund period. But eventually got them to replace me with a brand new iMac, and I was like, why not upgrade to the mac pro since i might be getting another faulty screen. So now Im running the mac pro 8-core 2.8ghz with 8gb of memory, and the eizo cg241w, can't complaint, life's good! Aperture is amazing now, no loading time, its instant!

Veltliner · Oct 11, 2008, 08:04 PM

Congratulations.

How much brighter has your screen been on the left side? I mean, was is visible even when no photography was displayed?

I can see it in side by side comparisons of photos, and that's where the pain lies, as you can't rely on what you see.

kerisabe · Oct 11, 2008, 10:18 PM

Thanks!

Yea I could see it without comparing pictures side by side. It was that bad and I see that there is definitely something wrong with the LCD if displaying a full grey background, it's not pure grey, I can see dark and light lines on the screen!

Veltliner · Oct 16, 2008, 02:53 AM

Originally Posted by kerisabe

Thanks!

Yea I could see it without comparing pictures side by side. It was that bad and I see that there is definitely something wrong with the LCD if displaying a full grey background, it's not pure grey, I can see dark and light lines on the screen!

Than it was much, much worse.

I guess the differences in color and luminosity on my display are just a drawback of an all-in-one design. And then there's the price to be considered.

Which still doesn't prevent me to jump out of my skin if I can't get exact color and luminosity reproduction.