CHROMiX

Calibrating LCD on Powerbook G4

Anyone ever have a need to calibrate an LCD on a Powerbook G4? I’m using a Monaco Optix XR Pro. Actually, my main goal is to calibrate a 23" ACD that will be hooked up to it. That appears to have worked fine, although at gamma 2.2 and native white, I get a luminance of 206cd/m2 with moderate room light…a lot brighter than I expected.

Anyway, I notice when calibrating the Powerbook LCD that the Optix software will actually first determine the maximum usable brightness (a step apparently not necessary for the ACD) and then allow you to dial in the brightness based on room lighting. Trying to dial in the brightness is like hitting a moving target. And when all is said and done, I get a measley 74cd/m2, which next to the ADC looks pathetic. I’m not really concerned too much about being exact on the Powerbook, but something comparable to the ACD would be better. Any thoughts?

mike

little update…There is an extra step when calibrating the Powerbook LCD, but it isn’t the “set max brightness” step as I indicated above. Here’s the steps involved with the Monaco Optix XR Pro software after calibrating your measurement device and setting white point/gamma, ambient light level, ect:

  1. set contrast at 100%, Brightness at 0%
  2. set contrast (not applicable to this monitor)
  3. set max brightness
  4. set brightness (until arrow is aligned at “good” indicator)
  5. optimize brightness for room lighting (until arrow is aligned at light level selected).
  6. measure color patches

Step 4 is the extra step that doesn’t show up when calibrating the 23" ACD. I’m assuming this step is determined necessary by the previous measurements. What’s weird is that during measurement of this step, I can adjust the brightness to 0% or 100% and after a few measurements, the arrow will align at or very near the “good” area. If I make an extreme adjustment, measurements will be off for a few cycles, but eventually the arrow pops back up to “good”. The screen can be barely visible and I can still get a “good” reading. :confused:

BTW, the “auto adjust brightness as ambient light changes” optnion is disabled in the system prefs…as well as the enhance contrast in unviversal access. Further BTW, I am now purusing this for my own curiosity and have long since stopped caring what the powerbook lcd actually looks like. :wink:

Hi Mike,
Regarding the workflow for LCD in MonacoOPTIX XR…the wizard first requests that you measure max contrast (if available) and then brightness. Once the mion and max brightness have been measured, the wizard should guide you through the process of setting the hardware to the optimum condition. In either case, you should have both “brightness optimization” and “ambient luminance adaptation” available.

In the case where you do have contrast available, the wizard will determine if you are “clipping” at the maximum contrast level and guide you to lower it. If the software does not detect a “clip”, the software will automatically advance to the brightness functions.

If you are in the expert mode (from prefernces), you can simply key in target luminance values and go.

If you are seeing lowere luminance levels after building a profile, there is a couple things you can do:either set the ambient option to “bright” (or simply skip the ambient option all together), or use a color temperature that is close to native for the pBook. The reality is that - if you choose a color temp that is far away from the native whitepoint, the software must sacrifice luminance to get there. Targeting a white point that is alreay close to the raw state means less correction and less loss in luminance.

Hope this helps.

Mike and Marc…Mike I have sent Marc a private email on my problem with Optix Pro and 17" Gateway 610XL LCD monitor.
After $1000’s of dollars on software and 100’s of hours of frustrated time, my evaluation profiles tell me(and other knowledgeable users and experts) that my monitor is way out of calibration. AND no one knows how to fix it.
I can’t go CRT because the 610XL LCD is a permanent fixture of the desktop. So if you do ANY image editing go CRT.
Maybe Marc has some input to this…

It is now being suggested that I get a 2nd monitor. A CRT…more bucks but is it truly worth it?? Advice seems to be changing on the parameters of a calibration device on a LCD. Wish the “powers to be” would have thought about that before a lot of us spending big bucks to find out our monitors are calibratable to the finest point!
Dan