A car's interior uses many different surface materials. For the interior design scheme to uphold a high level of quality, these materials must harmonise and be visually compatible. Experience and research have proven that a material's appearance and colour can be subject to change when under various types of light. Compositions of surface materials can also influence the way they are perceived together when the light they are illuminated by changes.

A study was performed where 21 interior surface materials were examined under a selection of white and coloured light. The materials consisted of ten décor samples, four grained plastic samples, four grained vinyl and leather samples and three chrome samples. The white light used consisted of daylight (CIE illuminant D65 at 6500 °K), fluorescent light (CIE illuminant F11 at 4000 °K) and incandescent light (CIE illuminant A at 2800 °K). The coloured light used consisted of six colours: red, green, blue, yellow, violet and turquoise. The materials were examined using the paired comparison method under all nine types of light, and the results were documented. Patterns were identified in the results and conclusions regarding different aspects of the materials were drawn.

The results showed that light has a strong impact on the perceivability and compatibility of materials, which aligned with previous research. Light materials were more affected by changes in light than dark materials, often taking on the colour of the light entirely. Red, green and blue light caused many metameric issues and materials were often straining to observe. Violet light caused less issues, and yellow and turquoise light even fewer. The results were summarised into a list of conclusions relating to the materials and their properties.

Implications of the results were discussed for three separate aspects: perceived quality, design and environmental. It is also important to keep in mind that conclusions drawn from results based on subjective judgements will always be prone to inaccuracies. Therefore, caution is advised when applying the results of this thesis, and compatibility tests should always be performed in addition to applying the conclusions.