Contrasts don’t need to be garish nor just black and white. Look for colours that the main users of the space would naturally enjoy and then contrast with different hues or bolder or lighter colours to provide adequate contrasts that will work for those who need them without resulting in clashing colours for those workers and visitors to the space who may not need to rely on the colour contrasts. Chosen well, colour contrasts should enhance the space for all users. LRV (Light ReflectanceValue) works on a 0-100% scale and are a measure of what the colour looks like. So if you need a contrast of 30% LRV then you need to choose two colours that have a LRV difference of +30% LRV, such as one colour with 40% LRV and one with 70% LRV to give the required colour contrast difference of 30% LRV. However if you have an LRV change of 30 you could end up with a dark green and a lighter green, which wouldn’t necessarily be enough contrast for someone who is colourblind. Ideally as well as a strength difference, you would also use contrasting colours (e.g. yellow with blue), different sheen levels and good lighting to help emphasise the colour contrast. You can use Resene colour codes to help identify colour differences. e.g. for the Resene colour code B54-058-237, the ‘54’ is the luminance (which is similar in many ways to LRV), the middle part ‘058’ is the saturation and the ‘237’ is the position on the colour wheel. Each of those elements can be used to compare colours to add additional contrast. LRVs only normally apply to solid colour finishes not stained finishes so if you are comparing stains you would need to visually check there is sufficient contrast. If comparing two surfaces from different suppliers that will be used side by side and need to be contrasting you may need to check how they are measured or do a visual check to ensure they provide sufficient contrast. In the case of Resene you can view the reflectance value for each colour in our online colour library, www.resene.com/colour – this gives you a quick reference to what colours of various LRV values look like. Colour blindness Colour blindness, or colour deficiency as the experts like to call it, is a condition in which certain colours cannot be distinguished and is most commonly due to an inherited condition. It is caused by a malfunction of the retina which converts light energy into electrical energy that is then transmitted to the brain. The conversion of light is accomplished by two types of photo-receptor cells in the eye’s retina: rods and cones. The cones are responsible for colour vision. Each contains visual pigments sensitive to wavelengths of light – red, green and blue. Most people can match all colours of the spectrum by mixtures of only these three fundamental colour sensitivities. The huge variety of colours we perceive comes from the cone cells response to different compositions of wavelengths of light. Defects in colour vision occur when one of the three cone cell colour coding structures fails to function properly. One of the visual pigments may be present and functioning abnormally. Or it may be absent altogether. The cones with the blue are almost always normal, so blue deficiencies are very rare. It’s the red/green spectrum that’s usually affected by the colour channels. 40 |