Tag Archives: blue

Colour Words

This week we had a three-day colour conference at the University of Leeds. You can see details of it here. This follows on from our successful event in 2019. COVID meant that it took 4 years to host our second conference but hopefully it won’t take so long for the next one. We had so many excellent speakers but one of these was Dimitris Mylonas (pictured) from Northeastern University London, UK who spoke about Colour Naming in Humanity-Centred Design. Dimitris is one of those people whose work I admire but I don’t get much chance to meet him even though we both live in the UK. I particularly like the use of on-line experiments in his research.

Last night I was chilling after the event finished and browsing youtube and I came across this interesting youtube video about the origins of English colour words. It is definitely worth a watch. It includes the idea that some ancient cultures didn’t have a word for blue and that they couldn’t see blue. Although I think it is true that they didn’t have a name for blue I am less convinced that they couldn’t see blue. As evidence for this people often cite Homer’s description of the sea as being wine dark in both the Iliad and Odyssey. If only I had seen this video the day before it would have reminded me to ask Dimitris what he thinks about this. I am sure he would have had something to say.

I don’t like Mondays

I don’t like Mondays blue. I do actually like Mondays, unlike The Bangles. But I don’t like blue. In this, I am out of step with the majority of people. Most studies on colour preference show that blue is one of the most preferred colours, irrespective of gender or culture. But, of course, some people don’t like it and I am one of those people.

The graph below is from one of my papers. It shows the per cent of people who selected each of 6 colours when we asked which was their favourite.

When we talk about liking or disliking a colour there are two caveats of course. The first is that there are lots of different blues. You might quite like one blue but not another. Most of the literature – including some of my own papers – not only focus exclusively on hue (as in the graph above) but only look at what we might call the focal colours of these hues. This grossly over simplifies the situation.

The second caveat is that although it is fine to talk about colour preference in an abstract sense, in practical terms you might like a colour in one context but not another. To give a ludicrously simple example: you might like a red car but not a red wedding dress. So we need to talk about context in a professional design scenario.

I am writing this because today I was walking in Leeds and heading towards the university where I work and I was reminded of this interesting blue structure that appeared a few years ago.

To say I don’t like it is an under statement. I think it is horrid. I cringe every time I see it. I generally don’t like blue but this particularly colour of blue is the most horrible.

Sometimes in Leeds I would go to a coffee shop that is associated with Harvey Nichols. They have rebranded it as Rabbit Hole Coffee. Imagine my shock when I saw the horrible blue that they used.

In a design context there is a role for blue and for this sort of blue. It is used quite a lot by Greggs and Tesco.

In these two cases it is a good use of the colour blue. In my opinion it looks cheap. And for Greggs that is fine. They don’t pretend to compete with Harvey Nichols. They want to communicate to their consumers that what they sell is not expensive and that is great. And it also works well for Tesco (although it is a slightly different blue to the blue used by Greggs). Tesco don’t specifically want to communicate that they are cheap but they do want to communicate that they are good value. Definitely not on the pricey side, as we say in the UK.

So even though I don’t like blue personally I can endorse its use by Tesco and Greggs. But the University of Leeds and the Harvey Nichols cafe? I think it is a really poor choice. I would have much preferred the lovely Leeds (legacy) green which you can see on the structure just to the left of the blue tower. Even a lovely red would nice. These are the University of Leeds brand colours, which have a gorgeous dark red,

with these two legacy colours:

Texas Design Week

I’m off to Texas on Monday for Texas Design Week. I will be taking part in two panel discussions – one in Dallas and one in Houston – invited by Harlequin (part of the Sanderson Design Group) with whom I have been collaborating for a colour of years now. Last year I did something similar in Atlanta for Atlanta Design Week so I know what to expect. And we have done have half a dozen or more such panels in the UK over the last 24 months. I will be sharing the platform with designers of course and my role is to bring some findings from the world of colour science to the table. The mix of science and design in the discussions is always a lot of fun.

My relationship with Harlequin started when I was asked to write a white paper about colour and its effect on people at home and in the workplace. You can download that white paper here if you are interested.

Talking about colour in our lighting lab

In the white paper Soojin Lee and I identified two different ways in which colour (and light) can affect us. We referred to them as emotional and physical.

The emotional effect is often caused by associations; we associate certain colours with certain ideas or memories. We might find a blue room relaxing, for example. There is some commonality between people (because we all live in the same world) but at the same time there are differences between individuals. This is the same reason why, for example, blue is a colour liked by lots of people, but that we can find individuals who don’t like blue. I am one of those.

The physical effect is more to do with the direct effect of colour and light on our physiology. For example, we need exposure to lots of light in the morning and we need to avoid such exposure at night, to keep our circadian system in a healthy state and to enjoy good quality sleep. There is evidence that blue light, in particular, is alerting and can keep us awake. Because we all have the same physiology there tend to be fewer individual differences in these effects.

Sometimes these two effects are contradictory and can even occur at the same time. It’s why a blue bedroom (blue-painted wall, blue curtains or blue bed linen) can be relaxing whilst at the same time exposure exposure to bright blue light can be alerting.

So is blue alerting or relaxing? It depends. It doesn’t actually make any sense to ask the question in that abstract way. We should ask whether blue lighting or blue paint, for example, is relaxing – and then we can have a meaningful response.

Brown is trending

I am not a fan of colour trends. What I mean by that is that I think sometimes there is an urge to generate new colour schemes twice a year which feels a little forced to me. And it is one of the reasons why we over consumer. This is particularly the case with clothes where – in the UK in particular – we buy clothes far too often. Our consumption of textiles is generally not sustainable.

But that said, I am not saying that there is no such thing as colour trends. Certain colours – and colour combinations – become desirable at certain times and I don’t think the whole thing is artificially generated. I just think the changes are not as rapid as the colour forecasting industry would have us believe.

But I am old enough to remember the 70s and I remember well the desirability of brown and olive green bathroom suites, for example. Nobody would use these colours as the basis of their interior design colour schemes today — would they?

Well, today I read that brown is replacing dark blue as a favoured colour for interiors when a moody dramatic look is the aim. The article in Livingetc suggests that the use of brown – a more muted colour – is more natural in its feel and that sales of brown-hued paint are rising. There are some interesting examples of the use of brown in the online article.

Colour Mixing

I really like this page by John Lovett about colour mixing.

We all know that you can’t mix all colours by starting from three primaries. You can’t do this in theory and you can’t do it in practice. You can’t do it with additive colour mixing and you can’t do it with subtractive mixing. In fact, with subtractive mixing, the oft-cited primaries of red, yellow and blue are actually not a very good choice.

Mixing red and blue pigments, for example, won’t give you a great purple. You will lose saturation and you almost certainly won’t get the vivid purple that is suggested by many colour wheels. However, John Lovett’s page explains how, if you do start with red, yellow and blue, you can do a little better by understanding that there is not just one blue and one red, for example. If you want to mix yellow and blue you should use a greenish yellow and a grreenish blue. On the other hand, if you want to mix blue and red you should use a reddish blue and a bluish red. This reduces the loss in saturation.

However, although Lovett’s advice is superb, you still can’t make all of the colours this way (though you can make all the hues of course). And arguably what Lovett is proposing is a six-primary system rather than a three-primary system. Lovett ends up proposing a six-primary system in an attempt to make the out-dated idea of RYB work.

Why yellow and blue don’t make green

[and why we should stop teaching it in schools]

You will find images like the one above, that show that red, yellow and blue are the primaries and that yellow and blue make green.

Sometimes this is represented as a colour wheel:

So some people say yellow and blue make green. And you will find other answers that say that yellow and blue make black. How can this be?

Well, we need to understand a little science to get to the bottom of this.

The figure below shows what happens when you mix an ideal yellow dye with an ideal blue dye. The blue dye reflects light perfectly in about a third of the spectrum (and absorbs perfectly in the other two thirds). The yellow pigment reflects light perfectly in about two thirds of the spectrum (and absorbs perfectly in the other third).

The problem here is that the blue and yellow pigments (between them) absorb perfectly across the whole spectrum. The people who say that yellow and blue make black are saying so because of this argument.

Note that blue is a particularly bad choice of primary because it absorbs so broadly across the spectrum. [Making the blue even purer would only make the problem worse by the way.] Yellow is a good choice of subtractive primary because it only absorbs in one third of the spectrum.

The problem is, the people who say that blue and yellow make black are wrong of course. Every child knows this. In practice, if we measure the reflectance spectra for blue and yellow pigments they don’t look like those ideal ones I showed above. For a start, they are quite smooth. Here is a reflectance spectrum for a real yellow pigment. (The reflectance factor, by the way, is the proportion – or per cent – of light that the colorant reflects at each wavelength.)

Notice that with a real yellow colorant, it does not reflect perfectly in the middle and long wavelengths and it does not absorb perfectly in the short wavelengths. It reflects and absorbs to some extent all the wavelengths but it absorbs more at the shorter wavelength and absorbs at less the middle and longer wavelengths. The same is true of a real blue colorant; it does not absorb perfectly at the middle and longer wavelengths. The consequence of this is that you don’t get black if you mix blue and yellow. You would get black if the pigments were ideal but they are not. We live in the real world. However, you certainly don’t get a lovely bright green as shown in the colour wheel with red, yellow and blue primaries. You would get a dark desaturated murky dirty greenish colour. The main reason for this is that the blue is absorbing too broadly. Interestingly, if you look at the artist John Lovett’s page he explains that to mix a yellow and blue you should use a yellowish blue (and a bluish yellow). 

Now let’s see what happens when we mix cyan and yellow dyes. We’ll start with the ideal colours.

It’s very nice. We get a lovely green colour. Cyan is a great subtractive primary because unlike blue it absorbs in only one third of the spectrum (the red or long wavelengths). Note that it is precisely because the cyan does not look pure that makes it a great primary – that’s why I get so furious about people saying the primaries are pure colours. The cyan looks bluish-green because it reflects in two thirds of the spectrum and only absorbs in the reddish part. Neither the cyan nor the yellow dye absorb in the middle (green) part of the spectrum and therefore the result of mixing cyan and yellow is a lovely green. Except it is not quite true. Remember, this is for ideal pigments. Real dyes do not look like that. Refer back to the measured reflectance spectrum for the real yellow pigment. In reality cyan and yellow do make green but the green might be a little less saturated than you may wish for because of the unwanted absorptions by the two dyes in the areas of the spectrum where ideally they would not absorb. (It was the great Robert Hunt, who worked for many years at Kodak – for those who knew him – who taught me about unwanted absorptions.)

Have you ever seen this happen. Of course, you have. Whenever you use a printer (which typically uses cyan, magenta and yellow primaries) to get a green, the printer is using cyan and yellow to make the green.

Remember those people who say that you can’t make blue because – yawn – it’s a pure colour that can’t be made by mixture? Well, have you ever printed out blue on a printer? Of course, you have. Let’s look again at our ideal primaries and see if we can explain it.

That’s right. Mixing cyan and magenta makes blue. The cyan absorbs in one third (the red third) and the magenta absorbs in one third (the green third) but neither absorb the short wavelengths.

John Lovett explains that you can do a decent job of mixing red, yellow and blue dyes, but only if you allow yourself to use multiple blues and multiple yellows, for example. If you want to do the best job possible using only three subtractive primaries, then the best you can do is to use cyan, magenta and yellow. 

So finally you can see that the best subtractive primaries are cyan, magenta and yellow because the cyan is red absorbing, the magenta is green absorbing and the yellow is blue absorbing. And what is more, you now understand why this is the case (rather than accepting dogma). You also understand why there is a relationship between the CMY of subtractive mixing and the RGB of additive mixing.

The optimal additive primaries are red, green and blue (I will cover this elsewhere). And for this reason the optimal subtractive primaries are cyan (red absorbing), magenta (green absorbing) and yellow (blue absorbing). 

But don’t be fooled by this lovely subtractive colour mixing diagram. You might not get such lovely blue, green and red colours when you mix real CMY primaries (either on your printer or with inks/paints). Why not? Because of the unwanted absorptions.

If you want to to know more you could do worse that get a copy of Measuring Colour, now in it’s 4th edition, and authored by Hunt and Pointer. 

This post gets quite a few hits so I will take this opportunity to direct you to my short series of youtube clips that describe the issues discussed in this post in a visual way. You can see them here. If you want something a bit more technical check out this short lecture on colour primaries or visit my patreon.

Or visit my Patreon page here for more analysis like this

what colour is your passport?

passport colours

Whenever I am travelling to a conference and standing in a line at an airport it seems to me that everyone has either a burgundy passport like me or a red one if the are from USA. It turns out that most passports really are the same colour as this great infographic shows. Well, one of only about four colours so it seems. It’s interesting the way they are grouped; I wonder why Africa tends to use green or black. For the full story see. here.

colour helps you sleep

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Light in our natural environment tends to be bluer first thing in the morning and redder at dusk.

Researchers from the University of Manchester looked at the change in light around dawn and dusk to analyse whether colour could be used to determine time of day. They constructed an artificial sky beneath which they placed mice and they then measured the body temperature of the mice for several days and their body temperature was recorded. The highest body temperatures occurred just after night fell when the sky turned a darker blue – indicating that their body clock was working optimally. When just the brightness of the sky was changed, with no change in the colour, the mice became more active before dusk, demonstrating that their body clock wasn’t properly aligned to the day night cycle.

According to Dr Timothy Brown: “This is the first time that we’ve been able to test the theory that colour affects the body clock in mammals. It has always been very hard to separate the change in colour to the change in brightness but using new experimental tools and a psychophysics approach we were successful. What’s exciting about our research is that the same findings can be applied to humans. So in theory colour could be used to manipulate our clock, which could be useful for shift workers or travellers wanting to minimise jet lag.”

I like pink

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Pink is one of my favourite colours. Generally, however, if you ask people what their favourite colour is, the most frequent response is blue irrespective of gender, age or culture. Adults, that is. Because most young girls prefer pink. There is a huge commercial machine that pushes girls towards pink and boys towards blue. I support the Pink Stinks campaign which I blogged about in 2009, but I fear its chances of success are slender.

In my 2009 I linked to a BBC article that noted that pink for girls and blue for boys was not always the case. People cite the Ladies’ Home Journal from 1918 saying:

There has been a great diversity of opinion on the subject, but the generally accepted rule is pink for the boy and blue for the girl. The reason is that pink being a more decided and stronger colour is more suitable for the boy, while blue, which is more delicate and dainty, is prettier for the girl.

For some reason I always thought that it was the association of blue with the British Navy in the first world war that started the association of blue with boys. But today I read an article that suggests that the association did not start until the 1950s!! Apparently in 1927, Time magazine surveyed 10 major departments stores across the country about how each store associated pink and blue with boys and girls. The results showed that most children dressed in gender-neutral clothing and typically wore white because it was easy to bleach and keep clean. It wasn’t until the 1950s that pink became a female colour according to Estelle Caswell. Read all of what Estelle had to say here.

What colour is the sky on mars?

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The cameras never lies. Or does it? Recently I had to take a photo for a medical case and before submitting it I had to sign to say that the photo had not been modified. I did this – but it was ridiculous of course. Many people have this idea that the cameras faithfully captures what the scene looks like and that, unless we intentionally manipulate the images (in photoshop, for example), then we have captured the truth. Nothing could be further from the truth – as the recent image of #TheDress showed.

The top photo above was taken and released by NASA in 1976 and shows a Martian landscape. The sky is blue. However, at the time, Carl Sagan said “Despite the impression on these images, the sky is not blue…The sky is in fact pink.”

You see the original image had not been colour corrected. Colour correction is a process that takes place on most cameras these days without the user being aware of it but in 1976 was not automatic. The process can compensate for the spectral sensitivities of the camera sensors (which may differ from one camera to another) or for the colour of the light source. The second picture (above) shows the colour-corrected image. Some people are now arguing, however, that the amount of colour correction applied by NASA is wrong and that the sky should not be as red as it appears on the second photograph. For the full story including some other nice images of Mars see here.