The idea of beauty being in the eye of the beholder likely originated in ancient Greece, possibly with Plato.
Shakespeare said more or less the same thing in 'Love's Labours lost', 1588. 'Beauty is bought by judgement of the eye'
But the Irish writer Margaret Wolfe Hungerford is credited with coining the idiom in its present form in her best-known novel, Molly Bawn (1878), which contains her most famous idiom: "Beauty is in the eye of the beholder".
Whilst judgment of beauty is subjective, the monitor on which you view the object is not!
What makes matters worse, is that if you process you image on a monitor that happens to render images poorly, the image may look acceptable to you, but will look dreadful to others who view your image on different monitors. Why should this be so?
A cursory perusal of Amazon for computer monitors, say, 21” monitors, will yield a price range from about £65 to more than twice that price.
Moreover, if you read the customer ratings of the various monitors, you will often find for the cheaper ones in particular, criticisms that the colours on the monitor screen are washed out. Why should this be so?
More often than not, it comes down to the quality of the screen calibration.
ICC Profiles
According to the International Color Consortium (ICC,) an ICC profile is a set of data that characterises a color input or output device. The profile describes the color attributes of a particular device. A device that displays color can be assigned a profile, and this profile defines the color gamut that will be displayed by this device.
Every monitor has a profile and, if required, it can be changed. Some monitors are provided with good profiles, others, not so good.
Some monitors can be too rich in a given colour so there will be a general cast of that colour throughout any image it displays. You may not be aware of this until you go through the process of calibration and compare the before and after renderings. The software controlling a calibration colorimeter will usually tell you this sort of information.
Variable parameters that determine how a monitor will render an image.
Brightness
Contrast
Saturation
Colour temperature
Gamma
It is these parameters that can be changed in the monitor’s profile to optimise, and standardise its output. By calibrating your monitors you can acheive two things.
- Optimise the way that the monitor will render images.
- Make all of your monitors on laptops, desktops or extra displays, render a given image in the same way.
Monitors also change their calibration properties over time as they age, so periodic re-calibration is advisable as time passes.
There are a number of monitor calibration colorimeters available over a range of prices. Sometimes there are more than one model of a given colorimeter, where the devices themselves are the same, but the software provided with them differs in its capabilities; the more expensive device having the more capable software.
The colorimeter that we use is a Spyder5 Express
The software that we use is the open-source software DisplayCal. This is high quality software that in combination with the Spyder5 Express, produces good calibrations.
The colorimeter hangs in contact with the monitor screen and it characterises the monitor based on information such as whether it is an LED backlit screen, whether it is a reflective glossy screen or a matt screen. It will tell you if the monitor is too rich in, for example, green light, and it will use the information it gathers during the calibration process.
Part of the process involves the software setting the area of the screen where the colorimeter is placed to a whole range of colours and it makes measurements as it cycles through a large number of colour and brightness changes.
This is a photograph of the screen with the colorimeter in place, providing a green area for the colorimeter to measure and analyse.
This is a photograph of the screen with the colorimeter in place, providing a white area for the colorimeter to measure and analyse.
This is a photograph of the screen with the colorimeter in place, providing a red/orange area for the colorimeter to measure and analyse.
The final result is a profile that can be applied to your monitor and can be kept along with the original profile.
It is very difficult to show the effects of calibrating a given monitor when viewed on a different monitor of different calibration status.
Below is an animation of two photographs of a monitor screen with and without a calibration showing a test chart.
Look at the animation, and you will get some idea of the improvement of the rendering of the test chart when the calibration is applied. The photographs have not captured the exact appearance of the computer screen, for example, the camera has not captured the left hand part of the chart as well as it has the right hand part; but they do give an indication of the type of improvement that calibration can bring to a monitor.
In addition to the instructions that come with the colorimeter or with software to control the colorimeter, there are many tutorials online explaining how it is done and why it should be done.
If your astronomical images don't look quite right, maybe they are too rich in the blue or another colour, or gradients in brightness don't show as clearly as you would hope; then maybe your monitor is significantly out of calibration. If your monitor has been used a lot and is starting to age, or maybe it is a budget monitor or the screeen of a budget laptop; then it may be worth investing in a calibration system to make the monitor perform as well as it can. With good, open source software such as DisplayCal, even a budget colorimeter can make a significant difference to the way your monitor renders the images that are of importance to you.
