Metamerism is when two colour swatches seem identical in one lighting situation and look different in another lighting situation. This could be the colour fan and the paint applied to the wall: During daylight, both colours look identical, but with interior lighting with a low-energy light source, the two look like entirely different colours.
We once had a large project in which the colour orange was used on the interior wall. The customer turned on the lights... and the colour of the wall looked olive coloured. When we held the fan against it, the selected shade in the fan remained the same colour of orange. This was a clear case of metamerism: the difference caused by the artificial light between the swatch and the coating of paint.
An orange colour impression can by created e.g. with an orange pigment or it can be created by mixing red and yellow pigments. Many artificial sources of light, in particular the newer ones, do not contain, like the sun (or classic lightbulbs) all colours of light. If orange, for instance, is not contained in a low-energy light, this colour is not reflected and the orange colour looks more greyish.
Caparol, together with the sample card manufacturer Schupp, has developed a new fan production method. This method makes it possible to produce, with our own Caparol products, colour fans mechanically. We therefore no longer use the special pigments for classical sample card production when manufacturing the fans, but use the colours from ColorExpress, i.e. the colours that are also used for tinting Caparol products. The "true colour" rules out the feared metamerism effects, which yields highest possible certainty and reduces complaints.