A sensation of colour is produced when radiant energy LIGHT enters the eye of the OBSERVER either directly or modified by some OBJECT that reflects of transmits it.Colours visually alter the proportion of a room, therefore it is imperative that colour is distributed correctly.
To use colour effectively it is important to know not only what it looks like, but also how it will behave in different conditions. The things which affect our perception of colour most are its relationship to other colours, its psychological impact on us and the light in which we see it.
Colours have temperature. We describe those colours placed at the red end of the spectrum as hotter, vibrant colours, whereas those at the the violet end as cooler. Although the impact is partly psychological, it has been suggested that some colours are actually hotter than others due to their light waves reflecting different frequencies.
Colours also appear to move and therefore affect our visual perception of space and scale. Warmer and darker colours bring surfaces closer, and cooler colours push surfaces back.
Colours will also appear to change depending on the colour that sits beside it. For example, when red is placed near yellow it appears bluer, near blue it appears yellower, near green it appears brighter. Always keep this theory in mind when choosing colours for your home, as the aubergine feature wall in your friends' home may look bright purple in yours. (This is a VERY common mistake!)
Because colour is reflected from light our colour perception is very sensitive to the amount and quality of ambient light.
While red appears red in natural light, it will look black in blue or green light. The yellow to white quality of most artificial light affects in particular the white and neutral colours. We also notice the effect of shadows caused by the placement of artificial light.
All of these factors contribute to the benefits of sampling colours before making the final decision. A sample pot of the colour in question is the only way to experience the true colour in the particular environment.