Agile Radiant™ Colour Viewing Cabinets allow you to use different light sources to detect Metameric effects
Metamerism is an effect where two different colour samples appear to match under one set of lighting conditions, but not under different lighting. It's not that easy to explain, but often it's all to easy to see.
The problem arises because the eye is only responsive to three colours - red, green and blue. The amount of each of these colours seen by the eye is normally referred to as the tristimulus values, X,Y,Z. So any conditions that produce the same tristimulus values will be seen as the same colour.
The stimulus to the eye depends both on the amount of red, green and blue in the light illuminating the colour sample, and the way that the pigments in the colour sample reflect or absorb these colours. Changing either the light source or the pigments used will change the resulting tristimulus value, and hence the colour as seen by the eye.
It follows that when you use different pigments to match a colour under a particular lighting condition, then change the light source, the colours will generally no longer match - the so called metameric effect. It is difficult to predict whether the error will be small or fairly dramatic.
As an illustration, imagine that the two sample patches have been printed side by side, and matched under 6500K Daylight conditions. When viewed in daylight they appear to match exactly.
However, when viewed under typical Tungsten home lighting, the printed samples definitely do not match!
Obviously, this is just a simulation. However, if you contact us, we will be pleased to send you some actual printed samples, so you can see this effect for yourself.
To detect metameric effects, the normal method is to use controlled lighting conditions, such as those provided in the Agile Radiant™ Colour Viewing Cabinets. You can then switch between different light sources to check the colour match visually. It is also possible to detect and quantify metamerism instrumentally using a spectrally based measuring instrument that supports different light sources, such as the Ihara S900 Spectrophotometer we offer.
A simple way to avoid problems of metamerism is to stick to PANTONE® Solid Colours. The pigments used are defined by Pantone, as are the formulae used to produce specific colours. Hence, the printed result should always match the specified colour, regardless of lighting conditions.
Go to main Colour Viewing Equipment page.
PANTONE® is a trademark of Pantone, Inc.
© Cherlyn Electronics Limited, 2007