Light and Sleep

knowledge, news, sleep, ,

There was an interesting article in The Guardian today about a new blood test that can detect whether someone is sleep deprived. The idea is to use it to prosecute drivers involved in accidents who have had less than 5 hours sleep. According to the article driving after less than 5 hours sleep is as dangerous as driving after drinking alcohol. Experts are divided on the ethics of this.

This was particularly interesting for me for two reasons. Firstly, because this time last week I was on a flight from Manchester to LHR, en route to Texas where I took part in a couple of panel discussions about colour psychology having gone to sleep at 11:30pm the night before and left the house at 3:30am after fitful sleep for less than four hours. During the 1.5 hour drive from Leeds to Manchester in the early hours I had felt completely awake; however, I wonder whether I would be able to make this journey in a few years if the legislation is introduced.

But secondly, because my own research is concerned with the effect of light sleep and the devastating effects that lack of sleep can have on our health and wellbeing. A discussion about this topic actually came up during the Texas trip. I would encourage everyone to listen to Matt Walker’s superb TED talk – Sleep is your super power. We now know that light plays a crucial role in maintaining a healthy sleep schedule. Healthy sleep is entrained by exposure to bright light in the few hours after waking and to lack of exposure to light in the hours before going to bed. There is debate about the relatively importance of the light being blue. The light-sensitive cells in the retina that are implicated in sending signals to the hypothalamus in the brain (from where the release of hormones is controlled) are maximally sensitive to light at about 480nm but there is some evidence that longer wavelengths of light could also influence alertness (in other words, the cones may also be involved). Here is one of my own papers on this topic:

Lin J & Westland, 2020. Effect of long-wavelength light on electroencephalogram and subjective alertness, Lighting Research and Technology, 52 (6), 763-774.

There is already growing research into the use of light and light-related products to help us to sleep better. As public awareness of this issue grows it is inevitable that interest in to this topic will increase. Perhaps such products could be used to mitigate the effects of poor sleep in situations such as the one I was in last week.

See my related posts

colour helps you sleep
non-visual effects of light

Bulls and red

knowledge,

I noticed a story today about a bull that escaped during a rugby game in France. Why would a bull even be there? I have no idea. But what interested me was the trope that was repeated in the article about the concern that one of the teams was wearing red shirts and that this could put those players in particular danger.

As you may know, bull fighters use a red cape during bull fighting events and this is popularly believed to be to enrage the bull.

However, it turns out that bulls are dichromats. They only have two types of cones – the light-sensitive cells in our eyes – and they are missing the long-wavelength cones. This makes them colour blind and red-green colour blind in particular.

It isn’t the case that bulls are enraged by red; it is the movement of the cape that irritates them. It is my understanding that the red colour is used so that the cape doesn’t show the blood. This was discussed in the first of my podcasts – do dogs see colour – which you can listen to here.

I don’t like Mondays

design, opinions/rants, , , , , ,

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

design, opinions/rants, psychology, sleep, , ,

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

design, ,

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.

Free Webinar on Colour Design and AI

Uncategorized, , ,

We have a free webinar tomorrow (Thurs 23 Feb at 2pm UK time) about colour and AI. Anat Lechner will present about this topic. Here is the abstract below:

We’re at a new age where artificial intelligence is becoming the most influential technology, a technology that once arrived, is poised to morph all aspects of our lives, irreversibly.

Artificial Intelligence rapidly moves into the mainstream, demonstrating greater production efficiencies, marketing precision and at times, creative design output than what humans generate. As cross-industry disruption escalates, designing products, brands and environments is being challenged. Traditionally, design decisions relied heavily on personal preference, past experience, anecdotal or company data, or costly market research, but advancements in big-data and AI call for the integration of new capabilities into the design process to better inform, inspire and validate design decisions

This seminar will review the emergent cross-industry AI-driven disruption, providing examples of creative cognitive technology applications in product, brand, urban and experience designs. We will then center on data-driven color design decision processes, discussing new colour data insights and tools to enhance and solidify companies’ creative capabilities, data assets, design practices, and talent bench-strength.

Anat Lechner, PhD, is a Professor of Business at the Stern School of Business, New York University where she focuses on disruptive innovation and strategic change. She is also the co-founder of Huedata Inc., the Color Intelligence Company that provides colour data and analytics to designers, strategists and researchers to aid product, brand and environment design decisions. A former Researcher at McKinsey & Co. Dr. Lechner has advised global Fortune 100 firms in the Financial Services, Pharmaceuticals, Chemicals, Energy, Food, Technology, design and Retail industries. She has numerous appearances in NYT, WSJ, Forbes, BBC, Time and other premier global media outlets. Anat holds an MBA and a PhD in Organization Management from Rutgers University, NJ.

The webinar is free but you need to enrol. You can do that here – https://www.eventbrite.co.uk/e/colour-design-in-the-age-of-artificial-intelligence-tickets-537415603537

inclusivity in sport

news, opinions/rants, ,

I really like this nice awareness video about colour blindness in sport – in football (or soccer, as you may know it) in particular. It is very well done and makes the point that it is not just about the spectators but about the players themselves – and even the referees!

I posted a few other comments recently about some recent activities in this area which you can see here and here.

However, despite the brilliance of the video about inclusivity in sport I want to make one point about the cone responses. The video states that the cones in the visual system are sensitive to red, green and blue light. There is a level of approximation where it is not unreasonable to say this – and to be honest, for this video it is probably fine. However, when we simplify things it can lead to misunderstandings which are then repeated when they really shouldn’t be.

The graph above shows the spectral sensitivity of the long-, medium- and short-wavelength sensitive cones. Note that neither is sensitive to just a few wavelengths; each has quite broad wavelength sensitivity. However, the L cone, in particular, is not even maximally sensitive to red. I took the table (below) from wikipedia but I think it is a reasonably summary of the colours that we normally associate with various wavelengths in the spectrum.

From this you can see that the L cone (the one that is sometimes referred to as the red cone) is maximally sensitive to light that we typically see as being yellow or even yellow-green.

One common assumption is that the cones are only sensitive to light that we see as being red, green and blue and it leads to people saying things such as – the visual system only sees in red, green and blue and then generates all the other colours form these. And this is a gross misrepresentation of course.

I gave a talk at the Leeds Philosophical and Literacy Society a week or so ago and it was recorded. In this talk I referred to this and related issues. If you would like to see it then you can do so here.

Man Utd change sock colour

culture, news, , , , ,

This weekend Manchester Utd played Middlesborough in the FA cup. We won’t talk about the result. However, so interesting that Utd changed the colour of their socks from black to white to make it easier for people with colour discrimination issues to enjoy the game. Above you can see a shot from the game with a simulation on the right of how it might look to a someone missing the L-class cone (red-green colour blind).

This comes just after I posted about the rugby game and the problem trying to discriminate between the red and green shorts of Wales and Ireland respectively. Given the news in that post that World Rugby is bringing in some legislation it does seem that colour blindness (as poor colour discrimination is often referred to) is finally being taken seriously.

Colour and Inclusivity

culture, news, , , ,

Interesting article today in the BBC about the colour of rugby shirts and the experience of viewers who may be colour blind.

According to one fan, the Irish and Welsh national kits are particularly difficult to distinguish for some people. As you can see from the simulation below, it is particularly challenging for protanopia (where the long-wavelength cone class is missing and the viewer is a dichromat).

Apparently, World Rugby has proposed new laws to help people affected by Colour Vision Deficiency (CVD), meaning teams may have to change kit from 2027 in the event of a colour clash.

However, it would not be difficult for one team to make their kit a little darker and one a little lighter to allow more people to enjoy the game and follow the action more easily.

In the image below, on the left you can see the original colours and on the right you can see the simulated colours for a protanope.

The top rows shows the colours that will be used in the match this weekend. The bottom rows show slightly shifted reds and greens that are more inclusive on the left, and their simulated appearance on the right.

Colour Matching and Cones

advanced stuff, knowledge, technology, , ,

Earlier today I posted something on quora about who many colours there are. It’s quite a long post. You can read it here. However, if you want the short cut the answer is 3-5 million. 🙂

However, I also linked to the post on LinkedIn and someone asked me a question about the relationship between colour-matching functions and cone sensitivities so I thought I would make a new post today about that topic. I have used my message on LinkedIn as the basis for this post but modified it a little to make it suitable for general consumption.

Here are two diagrams:

This shows the actual spectral sensitivities of the MLS cones in the human eye

The 1931 CIE XYZ colour-matching functions

It’s another common misconception that people get these two diagrams confused. The cone spectral sensitivities are the actual sensitivities of the cones in the eye. Although people often say that the eye responds mainly to red, green and blue light, it’s not so simple.  In 1931 the CIE measured the colour matching functions. One of the reasons that they did this was that in 1931 we didn’t actually know what the cone spectral sensitivities were; these were only known for sure in 1964. So in 1931 the CIE measured the amounts of three primary lights that an observer would mix together (additively) in order to match a single wavelength of light. And they did this for each wavelength. The second of the diagrams above shows the amounts of each of the primaries needed to match each wavelength on the spectrum.  Originally, the CIE used three lights (these were RGB)  or primaries. However, they mathematically transformed their RGB colour matching functions to create the XYZ colour matching functions. These are sometimes also known as the CIE colour matching functions or the CIE standard observer.

These are the original CIE RGB colour-matching functions

The point of these (XYZ) colour matching functions are that they allow us to calculate the CIE tristimulus values XYZ of an object if we know the spectral reflectance of the object and the light it is viewed in. The XYZ values are the amounts of the three XYZ primaries that an observer would, on average, use to match that object viewed in that light source. If two samples have the same XYZ values then they are a visual match; because an observer would, on average, use the same amounts of the XYZ primaries to match each. And this was the whole point of the CIE system; to determine when two colour stimuli are a visual match.  Had we known the cone spectral sensitivities in 1931 it’s possible that history would have taken a different course and that instead of having CIE XYZ we would simply calculate the cone responses LMS. And we could say that if two samples have the same cone responses they are a visual match. But I guess we’ll never know.

Now, if two samples have the same XYZ values then they will have the same cone responses. This is a bit technical but this is true because the cone spectral sensitivities are a linear transform of the CIE XYZ colour matching functions. They are also a linear transform of the CIE RGB colour-matching functions.

The colour-matching functions depend upon which primaries are used whereas the cone spectral sensitivities are more fundamental. Doesn’t this make the colour-matching functions arbitrary? Not really. Although the actual shapes of the colour-matching functions depend upon the actual primaries used, the matching condition does not. If two samples generate the same cone responses then the observer would match them with the same amounts of the XYZ primaries and the same amounts of the RGB primaries.

On this page – https://en.wikipedia.org/wiki/CIE_1931_color_space – you can see the cone spectral sensitivities and the RGB and XYZ colour matching functions.