Welcome to my blog

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I am passionate about sharing my knowledge about colour to anyone who is prepared to listen. I work as a professor of colour science at the University of Leeds, in the School of Design, but I have held academic posts in departments of Chemistry, Physics, Neuroscience, and Engineering. Sounds like a mixed bag, but my interest was colour chemistry, colour physics, colour neuroscience, colour engineering and colour design. You see I have come to believe that colour is the perfect meta-discipline and that to understand colour you need to be able to understand (but not necessarily be an expert in) different fields of knowledge.

One way to use this blog is to just browse through it and dip in here or there. However, another way is to click on one of the categories (that interest you) such as culture, design, fun, and technology and see posts in that area. You can find the categories on the right-hand side of the page if you scroll down.

You can also comment on the blogs. I really like this, even if you disagree with me. Someone once said to me if you put ten colour physicists in a room and ask them a question (presumably about colour physics) you’ll get 10 different answers. Well, I guess not all of you reading this are colour physicists. Given our different interests and backgrounds, and given the complexity of colour, it’s not surprising that we will disagree from time to time. And that is rather the fun part.

If you have a technical question you’d love me to answer you can click on Ask Me and post it there. You can also email me at s.westland@leeds.ac.uk. I am also offering more detailed information about colour on my patreon page so take a look there if that might be of interest. 

The Colourchat blog is now sponsored by Colour Intelligence

 

Colour Design Strategies

advanced stuff,

I have been in the School of Design at the University of Leeds for over 21 years. Before that I worked in colour engineering. Before that in colour neuroscience. My first degree was in colour chemistry. So I have had a varied career but colour has been at the heart of it. I don’t think I thought too much about design as a discipline before joining Leeds. But your environment influences you, of course. Most of mu PhF students at Leeds have been design students. And I have taught on many undergraduate and postgraduate design programmes. So I picked up a few things along the way.

In the video below I run through some of the key concepts I have picked up around colour design, especially in the context of packaging and product design.

In this video I mention some work by my doctoral student Luewn Yu which I would like to expand upon a little here.

This is the paper

In this paper we showed people lots of products in lots of different colours and we asked which one they would prefer to buy. We also, at the end, asked what was their favourite colour. For each product we also asked to what extent did they think the product colour was functional.

What do we mean by functional? Well, it’s where the colour is more than decorative. Where, for example, in some products the colour might denote how strong a solution is or where it might suggest that a product smells or tastes this or that way.

Take the products below:

We might expect the middle on to smell of lemons for example. And maybe the right-hand one to smell of apples (though in this case it is neutral or original). And take the product below:

If it was darker green we might expect it to be stronger.

So for each product we have a measure of how likely the consumer is to choose the product in their preferred general colour (we call this product colour consistency rate) and we also have a measure of how functional the colour is (we call this colour performance/functionality). Our hypothesis was that people would choose a product in their favourite colour if there was no performance of functional implication of the colour. On the other hand, we thought that people would be less likely to choose a colour in their general preferred colour if colour is somehow important or has some other implication.

And that is what we and what the graph of our results below shows.

So all the blue dots represent different products. On the right you have products where the colour signifies something (such as washing up liquid or mouth wash) and on the left we have products where there is no meaning to the colour (such as a corkscrew or a pair of scissors).

As expected, for products on the left the product colour consistency rare is high; that is people tend to choose these products in their general favourite colour if given the choice. On the other hand, for products on the right the product colour consistency rare is low; that is, there is no consistency between the colour of the product that they pick and their general preferred colour. This allows us to predict quite well whether it makes sense for a product to be offered in lots of different colours or not.

The most important thing about colour

advanced stuff, , ,

I have worked in colour pretty much all my life. In 1980 I started learning at the University of Leeds where I was enrolled on BSc Colour Chemistry. That was 44 years ago!

Since 1980 I have been learning, working, researching and teaching colour for almost all of those years. I have learned a lot and I am sure I still have a lot to learn. For example, only a few weeks ago learned that the colour name magenta is named after an actual town in North Italy. I discovered this when doing some research about colour names for the following video.

And I recently I have been learning so many new things from a book called The History of Colour by Neil Parkinson. I can’t tell you how much I am enjoying reading it. But more about that later.

I often say to people that the most important thing about colour that I ever learned is called the principle of univariance. I read about it in Brian Wandell’s book Foundations of Vision in the 1990s. It was discovered by someone called William Rushton in the 1960s. It is about how the human cones operate and it is so fundamental to explaining how colour vision works. It explains how we can discriminate between different wavelengths of light despite only have three types of light-sensitive cells that each have broad-band spectral sensitivity.

It explains why we have metamerism – which is where, for example, two spectrally dissimilar objects can look the same colour when viewed under one light source but then be a mismatch when viewed under a different light source.

It explains why additive mixing occurs. Why we can additively mix red and green light to get yellow. And it even explains subtractive colour mixing if you think deeply about it.

So the video How does colour vision work?, is really about how cones work and the principles of univariance.

Why are things coloured?

advanced stuff, , ,

Things are coloured because we have visual systems. In other words, without us – or some similar sentient being – there would be no colour.

“By convention there is sweetness, by convention bitterness, by convention color, in reality only atoms and the void.”, Democritus, 460-370 BCE.

If we eliminated all living beings from the universe there would be no colour, no sound, no smell. All that would remain would be physical stimuli.

I really believe this. But it doesn’t mean that colour doesn’t exist. It’s like saying that just because they are things that we experience – things that our brains produce – then pain and love don’t exist. Of course pain and love exist. But they don’t exist in the absence of sentient beings and the same can be said for colour. And all of our perceptions of course.

But this video – below – is not about that. It is about how everyday objects such as paints, plastics, textiles, prints etc. interact with light. Why do some objects absorb short wavelengths and others absorb long wavelengths.

For most objects it is all about dyes and pigments. Please watch the video below to hear more about this. And don’t forget to click like if it was worth your time.

How many colours are there in the rainbow?

nature

This is a short video I recorded about the way that we teach children that the rainbow is ROY G BIV.

It’s a simplification of course and it may be that it reasonable to simplify things when we are teaching small children.

If you like this sort of thing you might also like this article from The Colour Literacy Project. It is easy to understand. What is less easy to understand is why I recorded my video in the fog. You’ll see what you mean if you watch it.

The danger of blue light

lighting,

I recorded this video in my labs at the University of Leeds. We have a special lighting lab where we can adjust the spectral properties of the lighting in the room. I started the video and had the lighting automatically cycle through some colours. After a short while it became irritating so I had to pause brlefly and set it to one colour.

We use this lab to carry out various studies into the effects of lighting.

Here’s the video.

Here are some of our fairly recent papers.

Xia G, Li M, Henry P, Queiroz F, & Westland S, 2021. Effects of coloured lighting in the real world environment and virtual reality, Journal of the International Colour Association, 27, 9-25.

Lin J & Westland, 2020. Effect of long-wavelength light on electroencephalogram and subjective alertness, Lighting Research and Technology, x.

Lin J, Westland S & Cheung V, 2019. Effect of intensity of short-wavelength light on electroencephalogram and subjective alertness, Lighting Research and Technology, 1477153519872801.

You can download many of my papers from my publication page which you can see here.

Dark Yellow

design, opinions/rants,

I posted this on LinkedIn the other day and it has certainly a lot of arguments. So I thought I would post it here. The link is to my Patreon site but it is free to read (like many of the articles).

The issue is that when you darken a yellow it tends to go either redder or greener which led to my trite title – does dark yellow exist?

The worst of the comments is the person who replied – ‘I would start by reading Itten’. Of course, I have read Itten but I can’t imagine that saying someone should start by reading Itten would be a good answer to any question. 🙂

Anyway, Itten does show a diagram in his book that demonstrates the effect but I don’t think he explains it.

Anyway, onwards and upwards!!

Is black a colour?

knowledge, news,

Today I recorded by fourth video on the Colourchat youtube channel. You can see the video here.

I started with a very difficult question – where is colour? – which ended up having to be recorded in two parts. So it was somewhat of a relief to record this easier question – is black a colour?

That said, there are those who argue black is not a colour. There are also those who argue that black is the absence of colour or even the absence of light. I briefly discuss all of these issues in my video.

In short, I think that black is a colour, albeit an achromatic one. It is definitely not a good idea to define black as the absence of colour of the absence of light. Anyway, watch the video if you are interested and let me know if you agree with my view.

Colourchat on youtube

news, Uncategorized

During my recent travels (Thailand for AIC; and China) i was thinking about podcasts and youtube etc. and I had an idea for creating a series of youtube videos about colour. What I didn’t want to do was create a powerpoint presentation and speak over it. I think we are all bored with that aren’t we.

But inspired by a youtuber who was posting about medieval England I had the the idea of just speaking to camera. No fancy graphic or slick production. Just speak to the camera about a number of colour-related topics that I find interesting. At the end of the day it is about colour and so I do include a couple of images and graphics – after all, a picture paints a thousand words – but I try to keep these to a minimum.

I recorded the first of these two of these videos from my hotel in Thailand (which was a brilliant venue by the way – congratulations to the Colour Society of Thailand for their brilliant organisation. You can view this introductory video here.

I also recorded the second video in Thailand and the third one in China. The concept os that I will try to answers questions about colour. These are questions that the public has been asking me for the last 40 years. The first question I decided to answer was Where is colour?

It turned out that this is a very complicated question of course and I decided to address it in two parts. You can listen to these two parts here and here.

It’s an experiment I am conducting. Way back when the internet was barely functional (late 80s / early 90s) I posted to the internet something called the Colour Physics FAQ which was a list of questions and answers about colour.

Eventually, FAQs became old hat I stopped supporting it online though I made it available on Amazon as a small e-book for old times’ sake.

My Colourchat blog has been another way to speak with people about colour and has been reasonably successful. In 2021 I had nearly 100,000 visitors to the blog. But of late I have been less convinced that a blog can really get to people. So my youtube videos can be seen as another experiment in a long-line of experiments – some more successful than others – where I get to talk to people about colour. Let’s see how it does.

MSc Colour

news, Uncategorized, ,

I am really excited to announce a new Masters programme at University of Leeds in the School of Design.

MSc Colour is a postgraduate qualification that is launching in 2024. There are two unique aspects to the programme.

Firstly, it is inherently multidisciplinary. Colour is a natural meta-discipline and to study well it is important to have an open mind and to be prepared to stretch yourself beyond your natural academic area. We will recruit students from all disciplines: art, design, chemistry, computing etc. In the first semester all students will have to undertake some colour design, some colour material science and some colour imaging technology. This multidisciplinary approach is to key to our thinking. However, in the second semester students will specialise in one of three areas:

  • Colour Design
  • Colour Materials
  • Colour Imaging

Secondly, our programme is aligned with the Colour Literacy Project. The CLP, supported by the AIC and the ISSC, is an educational initiative to strengthen the bridge between art and science in 21st century colour education, while addressing common misconceptions and misinformation about colour. The primary objective of the project is to develop a colour education website, within a STEAM framework, which provides foundational, state-of-the-art resources on the art, science and industry of colour for teachers at all education levels. We will be paying particular attention to the common misconceptions about colour which can be found in some educational material.

I will be the Programme Leader for this new programme. For the last few years I have been teaching colour as part of MA Design at Leeds but I am super excited about being involved in a programme where the focus is colour. We have a really talented team of academics with wide experience and can’t wait until next September.

For further information visit here.