How to Calibrate a Monitor
With an i1Display 2

Part 11 - Ambient Light Measurement

Another useful feature of the Eye One Display is its ability to take ambient light measurements which will help those interested in setting up the ideal working environment for colour accuracy.  To a lesser extent it may also affect the settings you choose to calibrate to.

Assuming your Colorimeter is plugged in attach the ‘Ambient Light Head’.  If you examine the ambient light head you will see 3 tabs that need to snap into place. It’s a tight fit so I present the fat end with the two lugs first and gently press everything together. Be careful also when you remove the head not to force it. I release the lugs one by one starting at the fat end (Further info: Removing i1 Display Ambient Light Head ).

Next click the ‘Calibrate’ button as shown below


You should get a message saying ‘Eye One Calibration was successful’ Click the right arrow to continue.

Hold the Eye-One so that the senor is pointing out from your screen (you are measuring the light that falls onto the screen) and click the ‘measure’ button.


A great result would be around 5000k at 50 Lux. If the measurements at your workspace are outside the green bands shown, then from a colour accuracy point of view your work area is not as ideal as it could be. This doesn't mean you’re doomed to bad results when making colour adjustments on screen but you should be aware of the influences at play.


Illuminance is probably the easiest thing to get right since it's a matter of adding or subtracting lights from your work area.

I have observed that there is a practical relationship between Illuminance (working environment), Luminance (screen) and the lightness/darkness of someone's final images.  Taking our earlier monitor calibration settings of 100 cd/m^2 : If the light around your workstation is relatively bright, your screen will be relatively dim.  Often in this scenario your perception of the lightness or darkness of an image is distorted and you will feel the image is darker than it should be.  Consequently you might lighten it, too much , which will cause a lighter, thinner than expected print. 

The opposite is often true:  If the surrounding environment is too dim, many people end up darkening their image too much.  This is not the only reason prints turn out too light or dark but, if you are having trouble it is very much an aspect to consider.

There is no single figure that is correct for either monitor Luminance or environment Illuminance. The great thing about being human is that we are all different and this is why we need to tailor these variables to our own needs. Assuming the illuminance measured at you workstation is neither miles too bright nor miles to dim it is quite legitimate to re-calibrate your monitor to a lower or higher Luminance, if you feel it will help YOU get more accurate results.

Colour Temperature

The colour temperature at your workstation has an impact on colour precision.  Say for example your room is lit by ordinary halogen downlights.  The colour temperature is likely to be too warm at around 3400k.  Assuming you have light or neutral coloured walls; they will bath your work station in warm light.  This may influence you into thinking that the images on your screen are a little cooler (more blue) than they actually are which may cause you to warm them up slightly too much.

For colour critical work consider changing your ambient lighting to a D50 lighting solution. The best D50 light bulb is SoLux


It pays to optimize your workstation environment for ultimate colour accuracy.  If you are earning a living from your images this is a relatively small investment that will pay for itself, through the improved quality of your final images.