Monitor Calibration

Monitors, On-Screen Color, and Color Reproduction

The problem of colour monitors, on-screen colour, and colour reproduction is a complicated subject that involves a number of very different technical problems and different technologies. Let's get this discussion off on the right foot by stating right up-front that you can never accurately match your monitor's colour to your print job. OK, with that out of the way we can start to look at the problem and examine some partial solutions.

 

RGB vs CMYK Colour

The first problem to deal with is the way that computers display colour is the exact opposite of the way that colour appears when printed on paper. For a more detailed explanation of RGB vs CMYK color please refer to our earlier CMYK Color post.

Computer monitors create images using combinations of just three colours: Red, Green and Blue (RGB). These are the primary colours of visible light. This also how televisions display images on their screens. RGB colours appear brighter and more vivid specifically because the light is being projected directly into the eyes of the viewer. The monitor literally shines the coloured light directly into your eyes.

RGB colour is an "additive" process in which the three colours are combined in different amounts to produce various colours. It is called "additive" because you must add varying amounts of two or more colours to achieve hues and values other than the three basic red, green and blue colours.

Professional printing presses print full colour pictures by using the colours Cyan, Magenta, Yellow and Black (CMYK). In this "subtractive" process the various inks absorb the light reflected from the underlying white paper to produce the colours that your eye sees. The colours that you see are those colours which were not absorbed by the ink. It is called subtractive because when you subtract the other colours, the colour that is left is the colour that you see.

 

 

Because the perceived CMYK colour is made by light reflected from the printed page it can never be as brilliant and intense as the backlit colour on a computer monitor. It is also affected by the underlying paper colour, reflectivity, and the lighting conditions in the rooms where the page is viewed. As a result, CMYK is never as intense as colour when viewed on a computer monitor.

 

Computer Monitors Have the Blues

As a general rule, all unmanaged computer monitors are too bright and as a rule they are too Blue in colour (this may vary by manufacturer). To begin to approximate print production colour it is necessary to take some degree of control over the colour that your monitor displays. There are some basic free tools that come with some systems and Adobe supplies a Gamma colour adjustment tool with Photoshop. We recommend however that if you want to have more precise control that you make the investment in one of the relatively inexpensive devices designed to analyze your monitor's colour and to make a customized ICC profile which then adjusts that colour to the printing industry standard for colour displays.

 

Monitor Calibration Tools

To calibrate your monitor to the greatest possible degree it is necessary to use a specialized calibration device such as on of the ones listed below. These are reasonably priced devices and should be within the budget of any design professional. If used regularly, any of these will make a big difference in the day-to-day accuracy of your monitor. It is a good idea to search the internet before puchasing one of these devices because the price will vary by as much as 10-20%.

• Xrite i1 Display LT or i1 Display 2
• Pantone HUEY
• Datacolor SpyderTV or SpyderTV Pro
• Integrated Color ColorEyes Display Pro

Any of these mentioned above will adjust your monitor without a large investment. It is possible to spend much more on a calibrator which will also be able to help with printer calibration.

 

Basic Monitor Calibration Without a Calibrator

We recommend that you consider purchasing any of the devices mentioned above. It is quicker, easier, and the results are much better. However, if you choose not to invest in a calibrator then there are some basic things that you can do to help your monitor display colour. If you have Photoshop then you should use the Gamma tool to make some basic adjustments.

In general you should always set the Contrast to 100% and then adjust the Brightness down. The Gamma tool will give you a black and dark gray target that you use to adjust Brightness. Usually the goal is to just be able to make out the dark gray square on the black background. The Gamma tool will then lead you through a series of adjustments designed to neutralize the colours of your display and to remove any cast that is usually present (remember the Blues mentioned earlier). It is a very good idea to set the desktop backround to a neutral gray to remove any influence that the background or wallpaper will have on your colour perception.

The standard target gamma for printing is now 2.2 (older Macs were often set to 1.8 but 2.2 is the current standard). The colour temperature goal is 6500K.

If you don't have the Adobe Gamma tool then you can use whatever adjustment tools that may have come with your system (Macs have something similar to Gamma in their OS X). The goal is the same no matter what software you use. You can even use the controls built into the monitor itself if you have nothing else. Be certain to use a neutral medium gray desktop background when making any adjustment. You are trying to make this gray absolutely neutral. Small adjustments will shift its overall cast from Red to Blue to Green very quickly.

We hope this information is helpful to you but as always, if you need to talk to us just pick up the phone and call us on 028 9045 9864 or email us. Media Design and Print are always happy to help.