I hadn’t realised how important it is to calibrate a monitor correctly.
My former method of “calibration” was simply to set the monitor’s contrast to maximum, and set the monitor’s brightness to a value that looked comfortable to me. I didn’t bother changing any settings in software.
But I got caught out.
Last night I took some photos and tweaked them on my PC so they looked OK. I published them and thought nothing of it. But several of my friends commented that they looked a bit dark, and when I checked the pictures out on two of the computers at work, they were indeed too dark.
My badly-calibrated monitors at home caused me to wrongly edit an image. So I read up on how to calibrate a monitor. There are many ways, but the method I’m writing about here is nice and simple.
- If you have TFTs, they are sensitive to the angle you look at them. Tilt them so they face directly at you.
- Turn the lights off in the room you are working in.
- On the monitor, set the colour temperature to 6500K
- On the monitor, set the contrast to 100%
- Look at the gamma black chart below. Adjust the brightness on the monitor until:
- Bar A is just visible at the bottom
- Bar B is visible from the bottom to about halfway up the chart
- Absolute black on your monitor is now calibrated.
- Find how to adjust the gamma on your computer. For example, I am running the proprietary nVidia X driver on Fedora and it comes with a convenient control panel. You can use Adobe Photo Shop to adjust the gamma, or xgamma under X Windows on Unix/Linux systems.
- Now look at the gamma chart below. Sit as far as possible from the monitor and squint so the lines blur together.
- Adjust the gamma on your computer so the shade of grey completely across the gamma column is the same at 2.2.
- The monitor is now calibrated.
References
Jonathan Gazeley 