Tag Archives: design

Colour names affect consumer buying

design, ,

Have you ever wondered why, when you look at a rainbow, you see distinct bands of colour? You may see red, orange, yellow, green, blue, indigo and violet (though more likely you will not be able to distinguish between indigo and violet). We know that the wavelength of light in the visible spectrum – http://colourware.wordpress.com/2009/06/29/colour-101/ – varies smoothly and continuously, so why don’t we see a smooth and continuous colour spectrum? Why do we see distinct colour bands?

myspectrum

In my opinion the reason we see bands is because of something called categorical perception. We tend to want to group things that we perceive together into one class or another. But this grouping is not just a matter of putting things into boxes; it has an impact on how we perceive those things. We see categorical perception everywhere – indeed, I have often wondered whether even the periodic table of chemical elements is a true and accurate representation of how the world is or whether it stems from our categorical perception.

A recent study by Skorinko at the University of Virginia and colleagues at Rice University (published in Psychology and Marketing, 2006) finds that consumers have a more positive reaction to products whose colours are given rather exotic and flashy names such as mocha compared with the same products that are given plainer and genric names such as brown.

 untitled

 And how is that linked to the early statements I hear you ask (even though you asked very quietly)? Well, the authors hypothesise that the reason for the improved consumer reaction to the fancy colours is …. categorical percetption. The fancy names stimulate a more positive category than their plainer alternatives. It is also suggested that more ambiguous descriptions (mocha as opposed to brown, for example) yield higher consumer acceptance and safisfaction. I cannot resist finishing this blog with the last line from the paper by Skorinko et al. (2006) who write:

Indeed, the judgement of “that we call a rose” seems to be influenced by its name (Shakespeare, 1595). 

Orange wedding

news,

Tomorrow I’m flying to Houston to present at a meeting of the Society of Color and Appearance in Dentistry; http://www.scadent.org/. So it was a strange coincidence that I came across a news story today that there is a trend in Houston (of all places) for people getting married – possibly brides, though I wouldn’t be so sexist as to suggest that – to use orange as a key colour in their wedding decorations. Interesting to see that orange is still a fashionable and contemporary colour. I knew I was right using orange as a main theme for the appearance of this blog! For the full story visit http://www.examiner.com/x-11875-Houston-Bridal-Scene-Examiner~y2009m7d12-Orange-you-glad-your-wedding-colors-reflect-you

additive colour mixing

knowledge, ,

There are – broadly speaking – two types of colour mixing: additive colour mixing and subtractive colour mixing. Subtractive colour mixing relates to how inks, paints, dyes etc add together to form different colours; additive colour mixing refers to how light-emissive colour devices create colours. So we’re talking about how computer monitors work or how phone displays work.

The essential principle behind additive colour mixing is that we can mix together three colours – called colour primaries – and create a surprising range of colours. See my earlier post – http://colourware.wordpress.com/2009/07/08/what-is-a-colour-primary/ – for further details about colour primaries. The additive primaries are red, green and blue. Is there anything special about these three colours that justifies their use as the primaries? No, apart from the fact that if you use red, green and blue as the additive primaries you get a large gamut (range of colours that can be produced).  There is no reason why you couldn’t use orange, purple and turqiose as the additive primaries – it’s just the range of colours that could be created would be unsatisfactorily small. And nobody would like that!

So, we have red, green and blue as the additive primaries. The figure below illustrates how additive colour mixing works. Imagine that we have three projection lamps at the back of a hall – one has a red filter and so produces a beam of red light, and the other two use filters to produce green and blue beams. We project these onto a white screen and get three circles of light (one, red, one green and one blue). We then move the angles of the projectors so that the circles of light overlap. We get something that looks rather like this:

additivemixing_b

Where the red and green light overlap we get yellow. We get magenta and cyan for the other two binary mixtures. So,

red + green = yellow

red + blue = magenta

green + blue = cyan

And if we mix all three primaries we can achieve white (or other neutral colours). The primaries could be single wavelengths of light – so we could use a primary at, say, 700 nm (for the red) and one at 450 nm (blue) and one at 530 nm (green). In practice, most devices (CRTs, LCDs etc) don’t use single-wavelength primaries since it would be hard to create bright screens (gamuts are 3-D not just 2-D) but in principle could do so. It’s also important to note that different devices and different manufacturers use slightly different primaries.

But let’s imagine for a second that the three primaries used in the pictuire above are at 450 nm, 530 nm and 700 nm. Green light (530 nm) and red light (700 nm) additively mix together and generate yellow. When this happens what is being mixed and where does this mixing take place? Take a few moments to consider this before reading on.

Notice I said that they additively mix to generate yellow – I specifically avoided saying that they mix to generate yellow light. If we look at the part of the screen that is yellow we would see that we have some light at 700 nm and some at 530 nm. The wavelengths are not mixed; they don’t mix together to generate some third wavelength of light such as 575 nm (I choose this wavelength since monochromatic yellow light is about 575 nm). So no physical mixing takes place other than – I suppose one could argue – that the red and green lights are mixed in the sense that they are spatially coincident. But that’s not really mixing, for me, and certainly doesn’t even begin to explain why we have the sensation of yellow when we look at these wavelengths together.

So when we say that the red and green lights are mixed together to create yellow we should be aware that no phsyical mixing takes place. Indeed, one could argue that mixing is really the wrong word to use. Though as I write this I am struggling to think of a better one – suggestions on a postcard please.

When we look at the mixture of red and green light we see yellow – but the eye is still receiving the indivual wavelengths of red and green light. However, the visual response to this is that yellow is perceived. Indeed, a carefully composed mixture of red and green light could produce a yellow that is visually indistinguishable from yellow monochromatic light; but physically the mixture would still consist of light at 530 nm and light at 700 nm. If mixing occurs at all in any real sense it is in the perceptual mechanisms of the visual system. Indeed, at the heart of this matter is the way in which our visual pigments respond to light …. more about that another time.