I'm on my second new 20" iMac, both with the same display issues: a pronounced gradation from top to bottom, dark to light. The first one was considered DOA and returned. I thought it too much of a coincidence that 2 would have the same issue, so began researching. Many posts say the 20" uses a TN display, which is only 6 bit and uses software interpolation to display colors. Apple claims both the 20" and the 24"use TFT active-matrix LCDs, with slight differences in the brightness and contrast ratios.
The product specialist at Apple kept repeating that the gradation is "within acceptable range" for the product, but would not clarify what that range is. He did not have any other useful recommendations or solutions. The issue has been escalated to an engineer.
Has anyone else encountered this issue? I find it impossible to work because the screen is so unreliable. They claim it's a "consumer level product". I am using it in a professional office, but I wouldn't even want to make my family photo album in iPhoto on it.

Why not return it and get the 24" one? I find this iMac to be more than acceptable in terms of the video.

My original thought exactly, but when the product specialist pointed to the fact that they both use the same display I became skeptical. The info he sent me on the difference is:

Typical brightness: 290 cd/m2 (20-inch model); 385 cd/m2 (24-inch models)
Typical contrast ratio: 800:1 (20-inch model); 750:1 (24-inch models)

Humm , I heard the same from another member here

However I have a 20 inch and I don't notice any gradation at all , we also have a 24 inch . I do notice between the 2 iMac's the 20 inch does certainly have a more lighter or faded contrast , the 24 is much much sharper and richer .

Then again on the 20 , I have a sunset desktop photo so maybe that is hiding the gradation ?

For this type of problem I recommend going to the Apple discussion forums and see what posters have to say about this issue. There may be some good info on how to get your situation resolved.


http://discussions.apple.com/category.jspa?categoryID=111

Let us know what you find.. if anything.

Thanks for the suggestion.

My pleasure.... good luck.

It is a consumer level product, he was right about that. Not to be a wise guy, but that's why the towers are called Pro's.

Try this link. It appears you don't have the 6 bit display from the previous model, it is a good display, but maybe not consistent enough for pro color correction.

http://discussions.apple.com/thread.jspa?messageID=911545

I recommend to my customers if you're doing serious color or Graphics work, you'd be better off going for the pro line, a tower and a good monitor, or if you can't afford that and have the desk space, get a good external monitor for the iMac. You'll have plenty of screen space and a monitor to do your proofing on. The video isn't quite as robust in the iMacs as the MacPro, the video "card" is the chip on the logic board, and it uses your real RAM for video memory as compared to a tower with a dedicated video card and RAM on the card. The 24" have a better choices on video cards than the one choice of the 20". The better video card would not give better color, but better performance if working with really large files. If you don't need the video muscle, the 20" iMac is a good choice.

Below is a link where a couple of our local pro users were discussing their recent acquisitions. Unless you buy an Apple 24" monitor you'll need to get a Mini DisplayPort to DVI adapter if you go that route, around $25.

http://forums.mactech.com/ubbthreads.php/topics/428741

Welcome to the joint BTW.

I don't need a lot of video muscle which is why I went with another 20". I had been working on an iMac G5 for years with no screen issues until 11 capacitors bloated and/or leaked and it died. I expected the newer model to be better, instead it's a dramatic step backwards as far as screen reliability. I may be more color aware than the average consumer, but I'm not a high-end photo retoucher either. Still I can not see any way they consider this amount of gradation within acceptable range for any application. Unless I just have ridiculously poor karma and happened to get 2 bad displays in a row.

it can happen. I got 2 bad dishwashers from Lowe's and they were different brands!