Regarding how slowly or quickly a monitor’s display characteristics might change over time, I’ve been using the same monitor - an NEC LCD2190UXI - since somewhere around 2008. Over the years I’ve kept more or less complete (though very disorganized) profiling notes, including information on the uncalibrated display characteristics (ArgyllCMS command “dispcal -R”).
So for what it’s worth, over the last 9+ years, and always using the monitor’s native white point and gamma, and with the measured “White level” kept in the range 60-75 cd/m^2:
The measured “Black level” has stayed reasonably close to 0.24 cd/m^2, with no obvious trend up or down over the years.
The measured “Approx. gamma” has stayed reasonably close to 2.2 - which is what the manual that came with the monitor says it’s supposed to be - with no obvious trend up or down.
The measured “Contrast ratio” has stayed fairly close to 256:1, with no obvious trend up or down.
The measured “Color Temperature” started out around 5800K with a DE of around 5 or less, and over the years the temperature seems to be steadily trending downward and the DE drifting upward, currently measuring around 5200K, with a DE of around 10.
If anyone else has records of how your uncalibrated monitor display characteristics have changed over time, I’d be very interested. I’m guessing the reason the Color Temperature for my monitor is steadily falling and the DE rising might be because the CCFL backlight is getting dimmer over time.
Anyway, I suspect my monitor might be on the downward slope of useability - I’ve noticed that using my usual “no calibration file, use native white point and gamma” approach to profiling has resulted in neutral gray midtones looking a bit green. So for my latest monitor calibrating/profiling I’ve resorted to two changes in how I calibrate and profile my monitor:
I used the monitor RGB Temperature controls to set a custom white point, setting R=255, G=238, B=250, using DisplayCal to guide changes to the monitor RGB values.
I changed the colprof parameters from “-as” to “-aS”, which eliminates abrupt hue changes in the deep shadows of what are supposed to be neutral gray gradients. I’m still experimenting, and might also end up using a calibration file loaded into the video card LUTs.
Regarding the slowness of monitor profiling, it’s the calibration file that takes such a long time to create. On my reasonably fast computer a low quality calibration takes a couple of hours, and a high quality calibration+profiling is best left to run over night. The really frustrating part of making a calibration file is that there are so many parameters to experiment with, and every time you want to try a different parameter value, a new calibration file is required.
Does anyone know what part of the calibrating process makes it so slow? It doesn’t seem to be affected by the amount of RAM or the speed of the processor. Is it related to the color measuring instrument?
On another topic, I noticed that the uncalibrated Black level and Contrast ratio are both fairly much affected by how bright the ambient light is. I think it might be best to calibrate and profile one’s monitors with the room as dark as possible, preferably in total darkness, and at the very least with the lighting held constant thoughout the profiling process. But this isn’t the lighting conditions under which we actually use our monitors, so I was wondering what sort of ambient light control other people use while calibrating/profiling their monitors.