Category Archives: knowledge

oldest work of art ever

culture, knowledge, nature, news, , , , ,

I previously wrote about the finding of the oldest cave painting in the UK which was a 14,000-year old painting found in a cave in South Wales. You can read about that post here. Of course, the oldest cave paintings in the world are perhaps 30,000 years old; probably the Chauvet caves in France. Today, however, I read of a new finding: these are six paintings of seals that have been found in caves on the coast of Spain, about 35 miles east of Malaga, and thought to be about 42,000 years old.

The article claims that these paintings of seals are the oldest known works of art in the world. But are they? In 2000 the BBC reported that archaeologists in Zambia uncovered evidence that early humans used paint for aesthetic purposes far earlier than previously thought. The team found pigments and paint grinding equipment believed to be between 350,000 and 400,000 years old. The oldest pigments previously found were 120,000 years old.

PhD blogs

culture, design, knowledge, technology, , , , , , , , , ,

I just noticed that quite a few of my PhD students have blogs so I thought I would give them a mention.

Jason Kao is studying for a PhD in the generation of 3D movies – particularly interested in the effect of hue and saturation contrasts on the strength of the 3D percept (as in, red objects tend to appear forward whereas blue objects recede). You can read his blog here.

Jade Smith is undertaking a PhD to look at how we can understand more about how consumers use clothes in order to better design clothes that will be used longer. As you may know, our current consumption of textiles in the world is not sustainable even from the persepctive of the demands made of water during their manufacture and processing. You can read her blog here.

Maryam Da is undertaking a PhD in colour semiotics. Specifically, she is running a massive on-line global colour survey to determine the meanings that people attribute to different colours. She is also using a clever methoodology whereby each person does just a little bit of the experiment – in fact, we ask each person about just one colour. So there is not excuse not to help out. Please have a go at the survey – it takes less than a minute. You can read her blog here.

new colour journal

knowledge, news, professional, , , , , , ,

A few years ago I set up a new journal – Colour: Design and Creativity. What I wanted to do was create a journal where people interested in colour could communicate and discuss their research whether their background be scientific, artistic, design, or anything else. For me colour is inherently multi-disciplinary – it’s a sort of meta-discipline, in fact. And the richest discussion is likely to be discussion that enables people from many different backgrounds to contribute.

I set the journal up with the Society of Dyers and Colourists who seemed to share my view. But I guess it didn’t really work out and we needed to find a new home for the journal. So I Was delighted when there was interest from AIC – the International Colour Association. We have now launched the Journal of the International Colour Association and published our first issue last month: see http://journal.aic-color.org/ and click on browse issues on the right-hand side. I am slowly uploading the previous issues that were published as Colour: Design and Creativity but that could take some time.

The journal is free to view and free to publish in. Please take a look.

red makes you eat less

design, knowledge, nature, news, , , , , ,

Yesterday was the first lecture in my module (Colour: Art and Science) at the University of Leeds. In this module I look at colour from a multi-disciplinary perspective covering art, design, physics, history, philosophy, neuroscience, advertising and branding – all perspectives that are needed to understand colour or are strongly influenced by colour. Towards the end of the module I look at colour in branding and advertising and look at the effects that colours have on people’s behaviours and emotional states. One of the frustrating things about it though is that there is a lack of high-quality research about this. In fact, I would go so far as to say that there is more nonesense written about colour (in books and on the internet) than almost any other topic I know!

Take the effect of colour on appetite. Lots of websites and books will tell you the same thing. Red stimulates appetite and this is one reason, for example, why it might be used in MacDonalds’ interior colour scheme. On the hand, blue inhibits your appetite; one reason for this is often stated as being that blue foods are quite rare and therefore we are predisposed to not want to eat blue foods (though what about blueberries!!). But when people write this, how many of them have actually done any research or read any research about these effects? That’s what I mean about nonesense; people write it because they heard it somewhere or imagined that it might be true. Last week I came across some research on the effect of colour on appetite. In this research, published in the Journal of Appetite, and jointly carried out by staff from the University of Basel (Switzerland) and the University of Mannheim (Germany) it was shown that participants drank less from a red cup than a blue cup and ate less snack food from a red plate than from a blue plate. In other words, the opposite of what is commonly believed. The point of this is that more serious research needs to be done to explore the effects that colour has; come and do a PhD in my lab and help to rectify that!!

Of course, the research referred to above does not necessarily mean that people would prefer red food to blue food or that people would eat less food in a restaurant decorated in red rather than blue. It is exactly that sort of extrapolation that is partly responsible for all of the misinformation about colour that is everywhere around us. I have to confess that I myself am sometimes responsible for this misinformation since I was talking to the students last year about the appetite-suppressant properties of blue. I need to stop now …. and go and do some more research.

synesthesia

knowledge, ,

Synesthesia is a neurologically based condition in which stimulation of one sensory or cognitive pathway leads to automatic, involuntary experiences in a second sensory or cognitive pathway. People who report such experiences are known as synesthetes.

So, for example, people may involuntarily experience a colour whenever they see or think of a number. Many people with synesthesia use their experiences to aid in their creative process, and many non-synesthetes have attempted to create works of art that may capture what it is like to experience synesthesia.

http://colourfulanguage.wordpress.com/ is a blog by Lauren who lives in the UK, has synaesthesia, and likes it!

why are leaves green?

design, knowledge, opinions/rants, , , , , , ,

Why are leaves green? The most obvious answer is that they contain green pigments, the most abundant being chlorophyll and that chlorophyll absorbs the short and long wavelengths in the visible spectrum leaving the middle wavelengths to be reflected and scattered. However, the deeper question is why should chlorophyll absorb in the short and long wavelengths of the visible spectrum when there is more light available in the middle of the spectrum?

The spectral irradiance of sunlight varies with the time of day, the weather conditions, the time of year, and the latitude/longitude. However, I think it would be reasonable to say that by and large, in most situations, the peak irradiance is in the middle of the spectrum (that which we would normally associate with being green and yellow).

So if one assumes that evolution has produced a perfect engineering solution to this aspect of nature in particular then I think one may expect plants to absorb mainly in the middle part of the spectrum (and this would result in the bluish and reddish wavelengths being reflected and a purplish colour).

So why don’t we have a chlorophyll equivalent that is purple? I have come across a number of arguments.

1. One could go further and say that if a plant wanted to be really efficient it would absorb all wavelengths of the visible spectrum and would therefore appear black. So black, rather than purple, would be the perfect engineering solution. Given that most plants are neither black nor purple then I think we can assume that evolution did not find the perfect engineering problem or that the problem is more complex than we think. For example, it could be that a plant that is black would absorb too much light and overheat. Or it could be that chlorophyll evolved from some earlier light-sensitive chemical and that genetic mutations could lead more easily to chlorophyll than to purple or black pigments.

2. Taking this point further, I have heard it suggested that most plants evolved from earlier plants that lived under water and that absorbed mainly short wavelengths of light (long wavelengths – red – cannot penetrate much more than 1 m of water). These earlier cousins of the modern plant would most likely have been brownish. Indeed, if one looks today ay plants in seawater, green plants are only seen on the surface or at very low depths. So the ancestor of chlorophyll could have been a brown pigment which mutated into green chlorophyll more easily than it could have mutated into a purple pigment.

3. I have also come across the ‘early purple earth’ hypothesis. This suggests that originally most plant life on land was indeed optimally purple and that chlorophyll absorbed to take advantage of those wavelengths that were not already being gobbled up by the dominant species. Subsequently, chlorophyll proved more successful than its purple companion.

4. It could be argued that optimally absorbing light (and being purple) is not the most important thing and that there are other aspects of the problem that are more important. Green chlorophyll could be the optimal solution to this more complex problem.

In short, the real answer is … I don’t know. I am not overwhelmingly convinced by any of the above arguments.

If you enjoyed this post you may like to look at my special christmas post on carrots and why they are orange.

preferred colours

fun, knowledge, opinions/rants, , , , , , , ,

Many studies have been carried out over the last 50-100 years to look at which colours people like and which they don’t like. Although there is variability between individuals (not everyone likes the same colours) there is surprising consistency when the results of lots of different studies are compared. In short people like blues and greens and don’t like yellows and (to a lesser extent) reds. The hue parameter is probably the most important but brightness and colourfulness also affect colour preference. People tend to like brighter and more colourful colours than darker and less colourful ones. Just for fun, I have been running my own survey on this web site. You can still add your two-penneth worth if you like – please go to http://colourware.wordpress.com/2011/02/22/favourite-colour-poll/. Interestingly, my fun survey is also in broad agreement with all those previously published experiments. I found that people’s preferences were:

blue 19%
green 19%
purple 14%
red 11%
orange 8%
yellow 8%
pink 8%
black 4%
grey 4%
white 3%
brown 1%
other 1%

I am not sure what practical application there could be in knowing which colours are more popular. For example, my favourite colour is red but I probably wouldn’t want to buy a red coat. Though on average most people really like blue, this doesn’t mean it would be sensible to make a product blue without consideration of many other factors. In design, colour is almost always in context and that context makes all the difference in the world.

More interesting though is recent research I have read which proposes a reason why there is individual variation in colour preference. According to this idea, we like those colours that remind us of things that we like (we like blue skies and green grass). It could explain dark yellows and oranges are particularly unpopular; these colours are normally associated with some rather unsavoury things (dark orange is the colour of poo and dark yellow the colour of vomit). Further, if people have a strong affiliation with an idea/concept that is strongly associated with a colour, then they may have some preference bias towards that colour. It makes me think – I am a hug fan of Manchester United and red is my favourite colour; but do I like red because I like Manchester United or do I like Manchester United because I like red? I am too old to remember which came first.

colour management for beginners

knowledge, technology, , , , ,

Colour displays are now affordable and enjoyed by consumers at work, at home, on mobile displays and in cinemas. Consumers often take it for granted that there is good colour fidelity as images are transferred between different devices. So, for example, a red object in an image appears to be approximately the same red when the image is displayed on different computer displays, when it is printed, and when it is viewed on a mobile phone.

This colour fidelity is not easy to achieve. Different devices use very different technology to display colour images. For example, a computer display will mix together light from three primaries (red, green and blue) to generate a range (gamut) of colours. On the other hand, a printer uses completely different technology and typically uses mixtures of cyan, magenta, yellow and black inks to create the gamut of colours. Even computer monitors use a variety of different technologies (from CRT displays, which are becoming obsolete, to LCD, LED, and plasma technologies) each of which may use quite different red, green and blue primaries. Colour management is required to compensate for differences between the technologies (colour primaries, colour mixing, colour gamuts) between different image-display devices. This necessitates that the companies that produce image-display devices must cooperate so that the devices are able to talk to each other; this is achieved through the International Color Consortium (ICC) . The ICC is an industry consortium that was established in 1993 by eight industry vendors (including Microsoft and Apple). Today approximately 70 companies are members of the ICC whose goals are to “create, promote and encourage evolution of an open, vendor-neutral, cross-platform colour management system architecture and components”. The ICC system is implemented in terms of device profiles and colour management system. The device profile is a computer file that is associated with each device (printer, camera, monitor, etc.) that essentially contains information to allow colour to be managed. In the case of a computer monitor, for example, the device profile would include information about the monitor’s primaries that would allow the colour image to be adjusted to compensate for the properties of the monitor so that the colours are displayed correctly. The colour management system is software that manages how these device profiles interact with each other and is normally part of the operating system of the computer.

Thus, when users capture, view, or print images they are using colour management all the time even though they may be unaware of it. Though this level of colour management is built into software and device drivers and is broadly invisible to the user it does enable colour consistency for images when they are captured, viewed and printed throughout the world. However, this level of default colour management is far from perfect. It does not, for example, generally account for changes in settings for a device (for example, a user may change the contrast, brightness, or colour temperature of a display) so that colour fidelity is, in practice, only approximate. This level of colour fidelity is probably sufficient to satisfy about 90% or more of consumers for whom colour is not a critical issue. However, for professionals working in industries where colour is a major concern (e.g. design, retailing) a higher level of colour management is often required. For these users, it is possible to obtain systems (typically low-cost colour-measurement devices and associated software) that allow a user-defined profile to be generated for a particular device with particular settings. This user-defined profile then over-rides the default profile and should enable a better level of colour fidelity to be achieved. Nevertheless, colour fidelity is always likely to be an imperfect issue. It is difficult for colour-management systems to perfectly compensate for the fact that, for example, different devices may generate quite different colour gamuts (typically, the bright red on a computer screen cannot be achieved by a CMYK consumer-level printer).

For ICC see www.color.org

RYB primaries

knowledge, opinions/rants, , , , , , , , ,

There are two phrases I keep seeing written down all over the internet that cause my blood pressure to increase.

The first is that the colour primaries are red, yellow and blue (RYB). And the second is that the primaries are colours that cannot be made by mixing other colours. Neither of these statements are true, of course.

The first statement makes no distinction between additive colour mixing (of lights) and subtractive colour mixing (of paints and inks) but subtractive colour mixing is normally implied. However, RYB is a relatively poor choice for three colour primaries. The range of colours that can be produced is actually quite small. For most painters and artists it doesn’t matter because very few work in just three primaries – if they did so they would probably be frustrated by the small gamut of colours achievable. Many artists (painters) will use 10 or more basic colours to mix their palette. However, there is a group of people who care passionately about the gamut of colours that can be obtained by mixing three colour primaries – that is the people who work for companies such as HP and Canon. These companies make CMYK printers for the consumer market and their jobs depend upon consumers liking their printers. They understand that the largest gamut (in subtractive mixing) can be obtained if the primaries are cyan, magenta and yellow (CMY). The teaching of RYB as the (subtractive) primaries should be stopped. It’s already gone on for far too long.

One reason I don’t like the teaching of RYB as being the subtractive primaries, in addition to the fact that it is wrong, is that it confuses people who are trying to learn colour theory. This is because red, yellow and blue seem to be quite pure colours and this encourages people to hold the second belief I don’t like which is that the primaries are pure colours that cannot be mixed from other colours. If people understood that the primaries were CMY it would be less tempting to hold this belief about the purity of the primaries. Of course, if you make a palette of colours of three primaries then it is true that no mixture of two or more colours from that palette can match any of the primaries. However, there are other colours (that are outside the gamut of the primary system) that could be mixed together to match the primaries. This false notion of purity confuses the real issue – that is, that the subtractive primaries are cyan, magenta and yellow because the additive primaries are red, green and blue. Look at this picture below:

The additive primaries are red, green and blue and the secondaries are cyan, magenta and yellow. Correspondingly, the subtractive primaries are cyan, magenta and yellow and the subtractive secondaries are red, green and blue. Simple.

I wrote about this before so for a slightly different perspective see my earlier post.

Perhaps I am so agitated about it today because I am just watching England getting trounced by Ireland at rugby when the Grand Slam was so tantalisingly close. Or maybe I will feel just the same tomorrow.

blue appetite suppressant

fun, knowledge, , , ,

It is said that blue is an appetite suppressant and that red stimulates appetite. But is this really true? I would be interested if anyone knows of any studies into this.

I have also read that the reason that blue is an appetite suppressant is that blue food is very rare. I think blue food is less frequent than, say, green or red. But there is, of course, blueberries. And I just came across a type of mushroom that is naturally blue. It’s called Lactarius Indigo. I’ve also come across blue food more commonly in other places such as Japan.