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Home >> Photography >> Digital
X-Rite ColorMunki Photo review - Monitor Calibration and Profiling
December 14, 2009
Calibrating and profiling monitors
There are two ways to profile a monitor with the ColorMunki:
- based on the ambient light conditions of your digital darkroom, or
- based on a set brightness that you want to calibrate to, e.g. 90, 120, or 140 cd/m2 (candela per square meter)
The following screens show the ambient light method of calibrating and profiling an LCD monitor (most of the screen shots have been reduced in size to 600 pixels on the horizontal dimension).
Introductory screen shown the first time you start up the ColorMunki software
Select what you want to profile
The ColorMunki is aware of multiple displays
Some basic parameters for starting the monitor profiling process - I chose to measure the ambient light and I selected "Native" for the white point target in the drop down list shown above
The ColorMunki needs to be calibrated first before measuring the ambient light or monitor
The top setting is for measuring the ambient light
The software prompts you to measure the ambient light
This is the reading I get with all the lights turned off
This is the reading I get with just my regular ceiling lights on
This is the reading when I place the ColorMunki close to my floor standing lamp - notice that in the last three screen shots, the recommended monitor brightness is a scant 80 cd/m2
After doing the ambient light reading, you're ready to measure the monitor - where to place the ColorMunki is pretty evident
If your monitor has a Contrast control, you will be prompted to make some adjustments - my Dell LCD does not have a Contract control
After setting or bypassing the Contrast adjustment, you next adjust the brightness and here you can see the lowest brightness of my Dell still exceeds the ColorMunki's recommended brightness. After adjusting the brightness as best as you can, the ColorMunki will read a series of RGB colors, from brightest to darkest, as well as from white to black.
After completing the reading, the ColorMunki will prompt you to save your new monitor profile
When you are finally finished, you can do a before and after comparison. For what it's worth, I never noticed a difference with the before and after for my Dell LCD and only a very subtle difference with my Acer LCD.
My use of the ColorMunki for monitor calibration and profiling
I decided to try out the ColorMunki’s ability to profile the monitor based on the ambient light conditions of my computer room. The room can be considered dim as three pot lights in the ceiling provide the lighting in the approximately 8x19 foot room. I supplement the lighting with a floor-standing lamp that has the lamp facing the ceiling. I also have a desk lamp with a daylight balanced fluorescent bulb for viewing my prints.
I wanted to see what the ColorMunki would recommend for monitor brightness under different ambient light conditions. I turned off all the lights so that the only light came from the monitors and received a recommended brightness of 80 cd/m2. Okay, seems reasonable that the monitor’s brightness would be fairly dim in a cave-like room.
I turned on the ceiling pot lights, which gave me an ambient light reading under 200 cd/m2, which also resulted in a recommendation of 80 cd/m2 for monitor brightness. Turning on the floor lamp and positioning the ColorMunki close to it gave me an ambient light reading of over 400 cd/m2, but the ColorMunki still recommends a monitor brightness of 80 cd/m2.
At this point, I wondered just how bright my room has to be before the ColorMunki will recommend something other than 80 cd/m2. At 400 cd/m2, I would think that the monitors can be a bit brighter than 80 cd/m2, because 80 is even lower than the traditional recommended brightness for CRT monitors at 90 cd/m2. And, at 90 cd/m2, we were working in very dim ambient lighting conditions.
However, I’m only human and the ColorMunki is an objective measurement device, so let’s go with what it recommends and see how it works out. As it turns out, my big 30-inch Dell LCD cannot be dimmed down so low anyway. At best, I can get it below 130 cd/m2, but that’s by letting the monitor sit for a long time at the lowest brightness setting and then watching the brightness indicator slowly trickle downwards. I stopped measuring at 130, because who knows how long it would take before the reading finally stabilizes.
My 24-inch Acer can be dimmed down to match 80 cd/m2, so after calibrating and profiling both LCDs, I compared the two brightness levels with my print samples and I have to say that 80 cd/m2 is actually accurate, but with a big caveat.
80 cd/m2 is only accurate if you view the prints in the ambient light of my room with no supplemental light, e.g. using a desk lamp or print viewing station. If you hold the print (a reflective medium) and compare to the Acer LCD at 80 cd/m2 (a transmissive medium) , you would have a pretty decent match in brightness. However, remember that I don’t view my prints in ambient light, because one, it’s too dim and two, it’s not the typical lighting that I would expect others to view my prints. I use a desktop lamp to view and compare my prints to the monitor view and that’s when it dawned on me that, hey, don’t let the ColorMunki measure the ambient light, let it measure the light that I use to view the prints. That seems to me the key here, you want to match the brightness of the monitors to your print viewing condition.
I recalibrated the LCDs again, but this time, I started by placing the ColorMunki under the light throw of the desk lamp I use to view my prints, as seen in the photo below. I wanted to see what kind of reading the ColorMunki would give and it did not disappoint with a reading seemingly off the chart at over 2000 cd/m2 and finally, a recommended monitor brightness that is not 80 cd/m2. Instead, I received a recommended setting of over 280 cd/m2, as seen below:
This is actually too bright, because I don’t view my prints directly under the light. It’s more like using the light from the rim of the desk lamp’s shade to view the print, so the trick is to place the ColorMunki in a similar position. Doing this still gets a me a very bright ambient light reading, but the recommended monitor brightness becomes a more reasonable 215 cd/m2.
After calibrating the monitors to this recommended brightness level, I have achieved a nice consistency between viewing the print under the desk lamp and what I see on the monitor. That is very definitely a success in my book!
The brightness of the two LCDs is consistent, but the native WB of the two is different, which is another matter altogether
The Eye One Photo also has an ambient light measuring mode, but this feature is more to gather information about the brightness of your room and interestingly, the white balance of the room. The information allows you to make adjustments if you follow the recommendations to conform to ISO standards, but unlike with the ColorMunki, it's not an integral part of the monitor calibration process.
I suppose that with the CRT having been dominant for so long, it has conditioned us to think that we have work with very dim monitors and low ambient lighting conditions. With the transition to LCDs, many people complained about the brightness and the inability to dim the backlight enough to the recommended monitor brightness level, but that’s missing the boat and not utilizing the advantages of the LCD over the CRT.
No longer do we have to act and look like vampires by only working in dim light such that our skin has turned pale from the lack of exposure to daylight. It doesn’t mean that we can work willy-nilly with the blinds drawn to allow sunlight to drown our digital darkrooms. We still need a room that is consistent in lighting during the day and night, but we can work in much brighter rooms thanks to the LCD. While my home office is dim, it is consistently dim during the day and night and always needs the lights turned on when I’m working in it.
One last point about monitor brightness, while the goal is to get a match between print viewing and monitor view, the monitor view cannot be so dim that we can no longer see the shadow detail. When I was still calibrating the LCDs to within accepted recommended ranges (90 to 140 cd/m2) I always wondered why we had to work with settings that made seeing shadow detail so difficult. Now, with matching the monitor’s brightness with my print viewing conditions, that is no longer an issue, because the LCD is plenty bright enough for me to see all the details.
Although they won't look like a match for color and brightness in this sample image, there is actually a pretty good match between the two views; however, I will admit that the monitor is sitll more saturated and I suspect that I would need an Epson x990 series printer to get the print closer to what the monitor can display.
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