colour correction for iphone

Of course, one of the reasons (but by far not the only one) that the iphone has been so successful is the quality of the camera that is built in. It was certainly one of the features that made me switch from Nokia about 3 years ago after more than 15 years of loyalty to the swedish brand. So I was interested to read recently that the next iphone may feature advanced colour correction methods and promises to be even better than its predecessors. You can read about the story here.

Colour correction is necessary because different cameras use different RGB primaries and because the activation of the RGB sensors when taking an image depend upon the quantity and quality of the ambient illumination. So, for example, imagine the light was very very red, then the R channel of the camera would be more strongly activated than if the light was whiter. However, our visual systems are able to compensate for this so that most of the time we don’t notice objects changing colour when we move from one room to another or from inside to outside. Colour correction is inspired by human colour constancy and attempt to correct the images so that the objects in the scene would retain their daylight appearance. However, colour correction is difficult; that is, it is very difficult to get it right all of the time. One frustration I have is taking a photo of my band (I play drums in a covers band) under very colourful lighting. Often the images are very disappointing and lack the intensity of the original scene. That is because, human colour constancy is only partial and under extreme lighting things really do change colour markedly – such as under our intense LED stage lighting. In these cases I think sometimes the automatic colour correction is actually too much and I have found that I have to modify the images I capture on my mac to try to recreate what I think the original scene looked like. So auto colour correction – the state of the art – is certainly not perfect. Let’s hope this story about an advance made by Apple is true.

This is not yellow

A few people have asked me about this interesting and entertainig youtube clip – This is not yellow.

It’s worth looking at. It makes the point that when you look at colours on the screen (whether it is your computer screen, your TV or your mobile phone) although you see a full range of colours, all that is there is mixtures of red, green and blue light. In principle this is true – in practice it’s a bit more complicated because the screen doe snot emit just three wavelengths. For practical reasons the RGB primaries on a display are more broad band. Nevertheless, the essence of what is being said is true; when you look at yellow on the screen it is not a single wavelength that you would associate with yellow that is being emitted. Hence, the “This is not yellow”.

However, the clip doesn’t go far enough. It suggests that this is a problem with displays and that when you see a real lemon, for example, you are seeing real yellow because the lemon absorbs all the wavelengths of light except yellow (which is reflected). Sadly this is not true either. Let’s look at the reflectance profile of a typical yellow object. I can’t promise it is a lemon but a lemon would be pretty similar.

What this graph shows are the wavelengths of light along the x-axis and, along the y-axis, the per cent of each wavelength that the yellow object reflects. Notice that it does not absorb all wavelengths excecpt the ones that would be seen as yellow in the spectrum (essentially about 580 nm). Rather, the physical yellow object reflects all wavelengths in the spectrum because the reflectance is greater than zero at all wavelengths. The physical yellow object also absorbs all wavelengths in the spectrum to some extent because the reflectance is less that 100% at all wavelengths. Obviously some wavelengths are reflected more than others. But it isn’t even the wavelengths at about 580 nm that are maximally reflected. The yellow object reflects more red wavelengths than it does yellow wavelengths. So why does the lemon look yellow? For the same reasons that the lemon looks yellow on the screen; because the light being reflected activates the cones in the human visual system in a certain way. So I am not knocking this video – rather, I want to say that it makes a good point about displays but that this point also relates to colours in the subtractive world. It raises the issue of what we mean when we say something is yellow either on a screen or in the physical world.

is colour forecasting ethical?

Colour Forecasting is big business. What is it? Well, if you search on the internet you may find something like this:

Design firms and retail markets utilize forecasting services to predict trends in color. Color forecasting helps designers (who work a season ahead) what fabrics and styles will be popular in future months or years. Color forecasting resources help predict trends in the fashion industry, and also home home design.

This suggests that colour forecasting predicts which colours will be fashionable in the future; for example, next year. However, I think there is another way to look at it. I am not at all sure that it is a prediction process at all; I prefer to refer to it as a marketing process. This is what happens. A group of people work very hard and have a great deal of expertise and through their activity and global network they produce a ‘prediction’ of what colour will be popular next year. Normally the prediction is not a single colour but a colour palette; but for simplicity let’s assume that it is a single colour and it’s red. The last thing retailers want is stock they cannot sell so they are very keen to find out what the colour forecasters are saying. When they hear that red is going to be popular they make sure that they purchase and stock large amounts of red stuff. Fashion magazines such as Cosmopolitan and Vogue want readers to buy their magazines and want to be seen to be on trend and so they publish story after story about how the next big thing is going to be red. Now think about the consumer. The fashion magazines are full of red and the stores are full of red. What do you think the consumer is going to buy? Can you see why I think the process is more about consumer manipulation than it is about prediction (in the scientific sense)?

Actually, that colour forecasting is not a really a prediction process isn’t even my main gripe. Rather, it is that colour forecasting (and the fashion industry more generally) encourages people to buy more clothes than they need. Do we really need to keep up with the latest fashions? Our consumption of textiles is already unsustainable and we cannot go on behaving as we have done in the past.

One of the final-year students in the School of Design at the University of Leeds is undertaking a research dissertation in this area which I am supervising. She’s running a short questionnaire and needs as many people as possible to complete it. It’s very short; please take a look here.

SimCity for the Colour Blind

A while ago I posted about whether colour blindness was something that designers should take more seriously. After all, about 8% of all the men in the world are colour blind. Of course, this does not mean that they cannot see colour (the term, colour blindness is a bit of a misnomer) but it does mean that they have difficulty discriminating between colours that the rest of us can easily tell apart. In my original post I was referring to the computer game, Call of Duty, and whether the gameplay could be reduced for colour blind players who may have difficulty telling the various colour tags apart that appear on the screen.

So it was quite interesting that I just came across news that the developers of SimCity have added three special colour filters that make adjustments to the colours on screen so that colour blind players can better discriminate. A great idea – but about time!!

Colour blind Chelsea fans

Rafael Benitez has not exactly been the most popular appointment as Chelsea Manager. I can understand the Chelsea fans’ disappointment. I would be distraught if Benitez was brought in to head up the club I support. However, fair’s fair. This week Benitez was criticised by Chelsea fans for wearing a red tie rather than a blue one; red being the colour of Liverpool football club where Benitez used to manage and is perhaps suspected of still having loyal ties. However, as you can see from the photograph, he was clearing wearing an orange tie not a red one. What does this mean? Are Chelsea fans colour blind? All of them? Have a we discovered a new phenomenon? If anyone would like to fund research into colour vision of football fans please get in touch.

Creepy fashion collage

Really like this set of fashion images. You can view them at all at Chicquero’s blog at http://chicquero.com/2012/10/18/creepy-fashion-collage/

race for colour

Over the summer I was asked to take part in a BBC documentary about the recent discovery of the first colour movie film that was fond at the National Media Museum (Bradford). I met the presenter Antonia Quirke (who was very nice) and we filmed for half a day. In the end only a few minutes of our footage made the final cut. Still it was nice to be on TV and BBC1 at that!! For further details see here.

on-line test for colour blindness

Quite a lot of people are colour blind and have poor colour discrimination. There are tests that can be carried out and these include the Ishihara test (which is a screening test that I certainly remember from School) and the Munsell 100-hue test (where people have to arrange a number of coloured discs in order). These tests need to be performed whilst being viewed in daylight. There are online tests but these are less reliable – partly because the viewing conditions vary such a lot. I recently came across a new online test provide by X-rite. It seems to be based on the 100-hue test (or, at least, something similar) and I can see how it could work, despite being an on-line test). I just had a go. It gave me a score of 34 and suggested that for my age group (and gender) the best score was 0 (perfect colour acuity) and the worst was 99 (low colour acuity). Hmmmmmmmmm. I have a version of the 100-hue test and I can perform it perfectly. My real score should be 0. I have perfect colour discrimination. So, much as I like the X-rite test, I have not changed my opinion that on-line tests like these should be used for fun and should be understood to not provide an accurate assessment of your colour vision. On the other hand, it could just be bitter because I only scored 34.

1950s graphics

When I was younger I was a big fan of Marvel comics. I loved The Fantastic Four and Spiderman in particular. I remember that US-based comics (Marvel and others) around the 1960s included the most outrageous adverts that offered fantastic products at very low prices. I always remember wanting some of the sea monkeys and also some of the x-rays specs. Though they were inexpensive, USA seemed a million miles away to me at the time and the notion of buying something from the USA and having it delivered to the UK seemed too fantastic. So I never placed an order. Probably a good thing – check out this interesting review of the 10 most outrageous comic-book advertisements. See also here for more about the monkeys!!

I was reminded of all of this when I came across an article today in the Daily Mail about the work of Peter Stults, an American artist who has taken modern movies and imagined how they would have been advertised in the 50s and 60s. Really interesting and evocative.

ps. If you like Marvel you may like to read what I found out about the colour of the Hulk.

colour meanings in business

Interesting post about colour meanings in business.