Problems with 20" iMac monitor Profiling


I have a 20" iMac (glossy screen) running OSX 10.5.8 and am calibrating the monitor with a brand new Eyeone Display 2.

The problem I am having is that the monitor profiles are quite different from one to the next. If I calibrate the iMac in the morning then again at the same time the following day, there is a difference between the two profiles. If I apply each profile via the OS Screen preferences I can see the difference. I would expect to see a difference say over a 3-6 month period but not one day to the next.

I have trolled through these forums and others looking for people with similar issues but haven’t found any yet. I have also read through the Colorwiki pages to check the different options and settings etc.

The settings I am using within Eyeone Match are: white point 6500K, gamma 1.8 and luminance of 120. All pretty standard. I don’t use the ambient light check. I then just follow the instructions.

What am I doing wrong or what settings have I missed?


Hard to say, but I will make a couple of observations:

  • calibrating everyday can be problematic and you will see variations due to a number of reasons. Typically on a new monitor the standard recommendation is once a month. This should reduce the variations from ‘over’ measurement.

  • you might try to stabelize your ambient viewing so that the temp is consistent from calibration to viewing times. If the ambient light is variable then that will introduce variables into your viewing. Also, a darker viewing environment is preferred for consistent viewing. Not pitch black, but dark enough to reduce the effect of your environment.

Hope that helps,

Rick Hatmaker

On Dec 8, 2009, at 4:35 PM, "Passnga"wrote:

Thanks Rick for the reply.

The ambient light is quite stable even though it’s not the best.

If I understand you correctly, doing a calibration, say each day, you would see a difference?

I did recommend to the photographer to calibrate monthly and to use the Advanced mode.
This question came up because they did one calibration using the Easy mode and one using the advanced and saw a difference. They then went and did another of each and each one was different. I thought that doing this may cause issues though but didn’t know why.

I have gone back to them and again suggest they use the Advanced mode with the ambient light check and only do monthly.
Using softproof, we get a very close match between monitor and print after doing this. Proving it is working.

Thanks again for you reply.

As with a lot of color management functions, consistency is the key.
The Advanced mode has the user going through the process of turning the brightness up and down, while the Easy mode by passes this and merely calibrates the display at whatever brightness it happens to be at. One of the reasons why some high end displays have a DDC feature is that it takes away the chance of any user-introduced variability.

Looking over your post again, I see that you’re dealing with a previous-generation iMac and trying to calibrate to 120 luminance. Those iMacs will almost never be able to get down to 120 using only the Mac brightness adjustment. Most iMacs I’ve seen end up with a luminance of around 180 - 200 or so, even with the brightness all the way down. I can see where having the brightness this far down would cause some variability also.

We had an article in one of our newsletters that mentions this issue:

Hi Patrick

Thanks for your reply. I did read though article and it did cross my mind regarding the Luminance etc, I just didn’t want to confuse anyone too much who would read my post.

I will pass on this info to the photographer.

Thanks you for the amazing amount of info within the Colorwiki site. I wish I had found this years ago!

Thanks again for the replies.

Hope you all have a great Christmas and new year!