Intel iMac displays banding in gradients

I'm not sure if this is a problem with the display or just with certain gradients, but here it is. I set my background to a gradient of about 70% gray at top fading into about 20% gray at bottom. Looking at the screen from a normal viewing distance, I can see horizontal lines or banding in the gradient. I searched for possible solutions, including adding a blur or noise to the gradient, but while I was able to improve it, I still see slight banding in the gradient.
It is not really noticeable in gradients that stretch horizontally, but it is quite noticeable the other way around, though sometimes it's more noticeable than others.
Is this a problem with the display or with the way the gradient was created? I tried switching the color profiles from the default iMac profile to a few others, as well as trying to calibrate the display myself using the display preferences, but the banding did not go away, and I'm unable to find any other potential solutions. Is this a normal problem for iMac displays? Or should I be sending this in for repair/replacement?

I reproduced your situation, and noticed a slight banding as well. I am reminded of an article I read that revealed the use of 6-bit displays on certain MacBook models which don't live up to the claim of being able to display "Millions" of colors.
It would upset me to find out that my 24" iMac's display (not the video card) is incapable of displaying all 16 million or so colors it's supposed to.

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Intel imac display glitch and involuntary restart

Just want to know if anyone else has experienced this specific problem, there are plenty of complaints about intel imac displays but I can't be bothered to sift through them all trying to find a match for my problem.
A couple of months ago I was watching a video in quicktime and noticed that my screen was glitching and flashing fragmented diagonal lines - like a commodore 64 loading type thing. Then the spinning-ball came up and a force quit didn't do anything so I had to force shut down. I started up and it occured again. Then the screen went blank/black, but still lit up, and restarted without me doing anything. It also got stuck during start up the second time this occured. I panicked and ran out to buy a 500GB external drive, backed up all of my work and then re-installed mac osx from disk, archive and install job. This seemed to sort it and for the following two months it seemed OK. No sign of any problems.
Since then I have updated from 10.4.7 to 10.4.10 (which I have suspicion that it screwed the firmware in my motu 828 firewire audio interface, costing me a £130 repair - but that's another painful story).
It happened again tonight (the screen thing, not the motu). And the ball came up and I couldn't do anything. Force shut down, restart - screen glitching again. Then I had 2 unexpected restarts, one getting stuck in startup. Then a successful startup but accompanied by the glitchy graphics, mainly red/pink pixellated diagonal lines flickering in and out. I ran a disk first aid - no problems. Did a disk permission repair. Shut down and ran a hardware test, the first few minutes of the test the screen was still at it but then stopped glitching, hardware test found no errors (it was an extended test too). Now I'm back on it and it's all OK.
Any suggestions/similar stories?
When it occured 2 months ago I had the original ram that came with the imac. Now I have 2x1GB sticks of crucial ram.

That's it! Well, that's what I have. Unfortunately, I don't know about the cause, but I don't ever recall having it prior to an update going back about a year ago. I recall an update, and that update being immediately followed by some sort of Apple Graphics something-or-other. I feel pretty certain that's when I first noticed this. I just had my LCD replaced for another reason, but I think you'll agree, it's not an LCD issue. In my case, browser activity, scrolling up or down in a page, seems to be the most common trigger. I've also seen "pieces" of the torn page, on the screen when minimizing the browser to the dock (usually Firefox, but I think I've seen it with Opera and Safari too). Is there a way to find update packages installed somewhere? I'd know it if I saw it, and I'd definitely try removing that suspect package/update.
Message was edited by: geekboy2000 - corrected OS

Intel Imac display problems

I have an old intel imac (17 inch white screen) bought just over 5 years ago. The imac has just 'died', the screen will not display anything. It will chime on starting up and I can hear activity but nothing displays on the screen.
I returned it to my local Apple store, upon investigation they said the graphics card had gone (£500 to replace) so I bought a brand new iMac a few days ago.
All of my data is backed to up an external hard drive.
I run a database programme on the old iMac called 4D, which has a huge amount of data stored in it (all backed up).
I have installed the most current version of 4D on my new Imac, but it will not open the data on my back-up (error message: data cannot be published).
I have installed my old original version of 4D from my original bought CDs, but again it will not read the data.
The guy in the Apple shop gave me instructions on how to link my old 'dead' iMac, to my MacBook Pro via a Firewire cable, and using Target Disc Mode, I should be able to access the dead iMac hard drive on my MacBook ... have just tried this and the dead iMac hard drive will not show up on my MacBook. It does not appear on the desktop as suggested by the guy in the Apple shop, nor does it show up in System Preferences > Start Up Disk as an alternative disc to boot from.
What I need to do is access the 4D database on the dead imac, so that I can export the data as a text file, to put into a new application on my new iMac.
Althought the data is backed up to the external hard drive, it is backed up 'in the database' ... and I need to EXPORT the data, which I cannot do unless I can open the database ... which I can't !
I'm going round in circles with this, so if anyone can please point me in the right direction it would be much appreciated.
Many thanks
Rock of Ages.

make sure you execute the instructions for target disk mode properly, because your screen is dead and you won't see the icon displayed.
see here: http://docs.info.apple.com/article.html?path=Mac/10.6/en/8443.html
you may have to hold the T longer on the deadhead mac.

Anyone Have A Problem Free Intel iMac Display?

Seeing as how there are so many thread with people posting issues with their 20" and 24" iMac displays, I was just wondering if there is anyone who DOESN'T have an issue with theirs?
So far, so good with me, though it has only been a week. I will give my a more thorough examination tonight.

No problems here.
Remember these are Support forums: people come here to request advice on specific problems.
cheers
mrtotes

Calibrating an Intel iMac display using Spyder2PRO

Recently switched from Windoze to a 20" Intel iMac.
With previous monitors, I used the buttons on the monitor to calibrate.
The Spyder software asks what adjustments are available on the iMac, and since it is all in software I can't be sure. Backlight? Brightness? Color sliders? What is there is not apparent in the Mac calibration routine...
Anybody know?
Thanks,
Arthur
iMac 20 Mac OS X (10.4.8)

The software for the Spyder2PRO asks what adjustments
are available on the iMac monitor, and I can't find
them listed. Specifically, it asks if there are
adjustments for:
Gamma
White Point
Brightness
Contrast
Backlight
RGB Sliders
Kelvin Slider
Kelvin Presets.
Apparently, there are no RGB sliders, as the software
says they need adjusting but I see no way to adjust
them.
Thanks,
Arthur
iMac 20 Mac OS
X (10.4.8)
iMac 20 Mac OS X (10.4.8)
Check Backlight, its the only adjustment. Even though you might think its the brightness adjustment on LCD the brightness is conctrolled by the backlight. That's what Color Vision told me to do.

White Intel iMac display and crash fix

My 20" 2.16 GHz Intel Core 2 Duo had become almost useless due to freezes and crashes- with NO crash reports in the logs.
They were often preceeded by video glitches, so I assumed it was a bad video card- unfortunately soldered to mother board.
Apparently, from forum postings, this is not an uncommon problem. The computer would run longer if the day was cooler, but rarely more than 10 minutes, so I suspected it was aggravated by heat.
Then I found this post from Bodomann on an Apple Support forum:
"Following up on my previous posting regarding my son's late model 2006 iMac that required a $900 logic board replacement:
Turns out the problem is apparently related to a bad CPU temp sensor. I installed 'iMac Fan Control' (Google it) which reported the CPU temp always at 32 degrees Fahrenheit (obviously incorrect). The same software allowed me to adjust the CPU fan manually. After multiple trials I set the CPU speed to 2800RPM after which the system would run forever - never freezing with the dreaded grey box 'reboot me' screen. I tried several times reverting the software to default speeds and the system would always crash within 10 minutes. "
I downloaded free Fan Control 1.2 for Imac from Derman Enterprises (they have an Intel iMac and a Mac Book/Pro version). It installs as a system preferences control panel. I cranked up all three fan speeds. The fans sped up noticeably. Horizontal lines have gone from screen (so far), no color artifacts and no crashes yet. I may have a real computer back! Hope Apple checks this out-
The control panel also gives the temps sensors are reporting at the CPU, hard drive and DVD drive. The CPU sensor reports the CPU temp as 32 degrees F- which is clearly wrong, unless Apple has been installing little refrigerators inside.
So thanks to Bodomann for posting- Hats off and three cheers to Derman and Cristoph for source code.
http://www.derman.com/iMac-Fan-Control
http://www.lobotomo.com/products/FanControl/index.html

Foregone you have saved my life! I was fed up and disgusted with the way this machine was behaving, always freezing and crashing and with the crazy random horizontal lines. Then I downloaded the Fan Control 1.2 and have had a crash-free, line-less night ever since.
I had tried adding more RAM, cleaning the vents, the old "zap the PRAM" trick from back in the day, even my Mac guru buddy hadn't a clue what to do. After many searches on this forum to try to figure out the line issue (thinking it was a graphics card problem), not even thinking I could ever fix the crashing issue, I stumble upon your post and now I am the savior of the family. My computer game-loving 13 year old boy just about cried with joy. Now his games won't crash all the time!

Should I get a 20" or a 24" Intel iMac (display quality issue)

Hello everybody,
next week I'm going to buy a new iMac.
I was about to purchase the 20" but with 2,4GHz and the bigger graphic card.
Because I do a lot of graphic and video work.
Now I read that a lot of people seem to have problems with their 20" screen.
There should be a faded upper left corner (because of the hot HD). And the colors are different depending how you move your head. The upper part is much brighter than the lower part, and so on...
Now my questions:
- Does this affect only the first iMacs produced, or are the iMacs in the stores right now still affected?
- Is the 20" with the bigger graphics card (same as the 24") has a better display behaviour?
- Are there happy designers out there with a 20" iMac?
- Or is a 24" the only solution for a graphci designer (I'm afraid it's to big for my table).
Any thoughts, suggestions, experiences are welcome,
Jan

Good Morning Jan,
Well, from a business standpoint I have just approved a final document which will add the Apple iMac 20" to our student-side standards list. What this means basically is that we've tested, extensively, the 20" iMac and found it's quality (as a whole) to be above and beyond what we normally receive from our other vendors.
One thing to keep in mind is that when you read the posts here things seem a lot worse than they are in the real world, this is because the Apple Discussion Forums are intended for support purposes so the majority of people posting here have a very specific problem. What isn't reflected here are those out there who have had no problems at all with the iMacs and are happy computing along and will for many years.
From a Graphic Design point of view I think you will be unhappy with both iMac models, sadly, due to the glossy screen which is more oriented towards consumers. You might give thought to a MacBook Pro with an external screen as an option as the specifications are virtually identical to that of the iMac, and it's portable!
Hope this helps! 
David

20" Intel iMac - DISPLAY LOOKS YELLOWISH WHEN VIEWED FROM AN ANGLE?

Just got a brand new 20" iMac and the display looks great when looking at it 'straight on', however when viewing the display from an angle (and just a slight angle) all of the white and lighter colors in a photo change to an annoying 'yellowish' color...go figure?
Is this normal or ???
Are there any settings to adjust in the System Preferences / Display?

Thanks George for the link...
Wow...little did I know about the dreaded viewing angle of a TN display. In fact, I went to an Apple Store yesterday and checked out several 20" and 24" iMacs and every 20" iMac had the viewing angle problem while the 24" iMacs showed no signs of this issue.
I plan to return the 20" unit and upgrade to the 24" iMac...thank goodness for the 14 day return policy, however with the 10% restocking fee...ugh!

Top Intel iMac display dissappoints versus TV

Why is it that DVDs played at full screen on the acclaimed high def. 24" iMac 1920 x 1200 screen (the pricey one) look so very much softer than on a basic TV?

Hi Prof.,
commercial DVDs are usually DVD-9, meaning a size of approx. 8,5GB to use, whereas most DVD-R (other then DVD-DL) have a size of approx. 4.3GB.
Now, when both have the same movie on it of about 100mins, the movie data has to be two times compressed on the DVD-R than on the commercial DVD.
This results in a lower quality of the movie pictures.
As for your TV, what TV do you have (Plasma, LCD, CRT) ?
Most plasma and LCD TV in that size have a resolution of up 1368x720 (or less, if older), whereas a CRT TV almost always has a resolution of 720x576 !
So, when playing a DVD on a CRT TV each DVD-pixel exactly matches the CRT-pixel.
On LCD-TV one DVD-pixel is displayed using 1.90 LCD-TV-pixel in width and 1.25 in height.
Also, they use certain picture-improving algorithms on a hardware level.
The HD content for quicktime can be found here: http://www.apple.com/quicktime/guide/hd/
Download one or two of them and see for yourself, what the iMac 24" can show, if provided with the best content.
Stefan

Intel iMac won't recognize external display with Dynex mini-DVI adapter

I've got an original Intel iMac with a Mini-DVI connection on the back. I'm attempting to hook it up to an external display (a plasma screen, in fact). I picked up a Dynex Mini DVI to Video Adapter DX-AP100 for Apple. This connector has a mini-DVI connector on one end, and both a video-out and an S-video-out on the other.
When attempting to use the adapter, the iMac does not recognize that there is an external display connected. Here are the facts:
The external display: I've tried this with a Panasonic Plasma screen connected directly through S-video, as well as a Pioneer receiver (one that switches video) connected both through s-video and composite video. And yes, I've got the settings on the TV correct. I've also tried this with a Polaroid LCD TV connected via S-video and composite video.
I did notice that when I click "Detect Displays" while the Plasma was connected, the plasma briefly "flashed", implying SOMETHING was happening, but still no dice.
Anyone have any experience with this Dynex DX-AP100 that could share some wisdom?
OS: v10.5.6
System Profiler:
ATI Radeon X1600:
Chipset Model: ATY,RadeonX1600
Type: Display
Bus: PCIe
PCIe Lane Width: x16
VRAM (Total): 128 MB
Vendor: ATI (0x1002)
Device ID: 0x71c5
Revision ID: 0x0000
EFI Driver Version: 01.00.068
Displays:
iMac:
Resolution: 1440 x 900
Depth: 32-bit Color
Core Image: Hardware Accelerated
Main Display: Yes
Mirror: Off
Online: Yes
Quartz Extreme: Supported
Built-In: Yes
Display Connector:
Status: No display connected

Yeah, I realize S-video is limiting, but I'm trying to keep things as simple as possible. The TV is mounted to the wall and there are not currently any DVI or HDMI cables coming out of it. There's an S-video input from my receiver that I'd prefer to use since it's readily accessible already. In the end my goal is to use Netflix "Watch Now" on the TV, so I'm not too worried about video quality.
and before someone asks if I considered that the receiver's S-video input might be the problem...I tried taking the s-video wire from the stereo and plugging it directly into the adapter. No dice.
ONE ADDITIONAL PIECE of information...while trying to get this to work on an LCD monitor, I plugged the composite video connection from the TV into the adapter. Suddenly the Mac recognized an additional monitor, but it saw it as a VGA monitor, not as s-video or composite video, and no signal went to the TV.
I'm considering trading in this adapter for a mini-DVI to VGA adapter, but that really won't help me with the connection to the TV.

User Contributed Tips in Intel-based iMac Your Intel-based iMac Display

*The following User Contributed Tips are located in the Intel-based iMac > Your Intel-based iMac Display forum:*
a brody - Using a second Mac as a display for a first
http://discussions.apple.com/thread.jspa?threadID=1587927
Publish date: July 7, 2008
*The following related tips are located in other areas of Apple Discussions:*
See also User Tips Library

My 20" 2.16 GHz Intel Core 2 Duo had become almost useless due to freezes and crashes- with NO crash reports in the logs.
They were often preceeded by video glitches, so I assumed it was a bad video card- unfortunately soldered to mother board.
Apparently, from forum postings, this is not an uncommon problem. The computer would run longer if the day was cooler, but rarely more than 10 minutes, so I suspected it was aggravated by heat.
Then I found this post from Bodomann on an Apple Support forum:
"Following up on my previous posting regarding my son's late model 2006 iMac that required a $900 logic board replacement:
Turns out the problem is apparently related to a bad CPU temp sensor. I installed 'iMac Fan Control' (Google it) which reported the CPU temp always at 32 degrees Fahrenheit (obviously incorrect). The same software allowed me to adjust the CPU fan manually. After multiple trials I set the CPU speed to 2800RPM after which the system would run forever - never freezing with the dreaded grey box 'reboot me' screen. I tried several times reverting the software to default speeds and the system would always crash within 10 minutes. "
I downloaded free Fan Control 1.2 for Imac from Derman Enterprises (they have an Intel iMac and a Mac Book/Pro version). It installs as a system preferences control panel. I cranked up all three fan speeds. The fans sped up noticeably. Horizontal lines have gone from screen (so far), no color artifacts and no crashes yet. I may have a real computer back! Hope Apple checks this out-
The control panel also gives the temps sensors are reporting at the CPU, hard drive and DVD drive. The CPU sensor reports the CPU temp as 32 degrees F- which is clearly wrong, unless Apple has been installing little refrigerators inside.
So thanks to Bodomann for posting- Hats off and three cheers to Derman and Cristoph for source code.
http://www.derman.com/iMac-Fan-Control
http://www.lobotomo.com/products/FanControl/index.html

Use G5 iMac as external monitor/display for Intel iMac?

I have a 24" Intel iMac and a 20" G5 iMac (which is sort of mothballed now).I was wondering if it is possible to use the older iMac as an external monitor, mainly to save the expense of buying a "proper" external display when there seems to be a perfectly usable one sitting there in the G5 iMac.

translate.google.com.
Actually, it didn't translate very well. But the instructions are basically how to wire up an adapter cable. The G5 iMac appears to use standard DVI signals, so you just need to make a DVI cable to plug in to the internal connector. The table between pages 7 and 8 is what you want. If you've used a soldering iron around electronic devices before, that table is pretty much all you need. The picture of the backside on page 9 is neat. Using the ethernet connector hole to route the wiring. Almost looks like it came from the factory that way.

Intel iMac with failed LogicBoard - can I use it as display for my MacMini?

I have a Intel iMac with failed logic board (the display comes up while booting sometimes and sometimes, it doesn't). I bought a Mac Mini afterwards. I connected it to a Dell monitor with HDMI and the results aren't great. I experience interminttent video losses (Grains on screen every 1 minute or so).
So, I am now thinking about using my failed intel Imac as a display. Will it work?

No, the failed imac is dead until you replace the logic board.

HD support for 23" cinema display with a 20" intel Imac?

By using a 23" HD cinema display as a second monitor, will it still do HD even though the 20" intel Imac does not show HD? Is there anything special I need to do enable HD in this configuration?
imac 20" Mac OS X (10.4.8) dual 23" HD

I just received my intel 20 in IMAC and tried to hook it up with my 23 in cinema HD display. The display looks awful - lots of flickering, very grainy, all pink and blue. Thought it was the adapter (DVI to mini DVI), so I changed it. Tried clicking the "detect display" button, tried resetting PRAM, changing resolutions, all with no improvement. Plugged the display back to my old powerbook 15 in and it was picture perfect. My IMAC also has an upgraded 256VRAM. Am I missing something? Any recommendations are welcome.
Imac5,1 Mac OS X (10.4.7)

Why won't my Intel iMac boot up, either from the internal hard drive or the DVD drive? It just displays a light grey screen, without any other icons, etc. The fact that it won't boot from the original system DVD is what baffles me the most. Any ideas?

Why won't my Intel iMac boot up, either from the internal hard drive or the DVD drive? It just displays a light grey screen, without any other icons, etc. The fact that it won't boot from the original system DVD is what baffles me the most. Any ideas? It uses the latest version of Mavericks. Thanks!

If the C key for Install Disc or R Command for OS X Recovery startup commands are not working, try holding the Option key for the Startup Manager.
see > Startup Manager: How to select a startup volume
If that does not work and you using a wireless keyboard, it may have become unpaired and you need to dig up a USB keyboard to invoke the startup commands.
For more on gray screen, see > Mac OS X: Gray screen appears during startup

Intel iMac displays banding in gradients

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