Monthly Archives: September 2012

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.

Race for colour

The films were made by a young British photographer and inventor called Edward Turner, a pioneer who can now lay claim to being the father of moving colour film, well before the pioneers of Technicolor.

The footage will be shown to the public from 13 September at the museum in Bradford. And a BBC documentary, The Race for Colour, will be broadcast on 17 September in the Yorkshire and south-east regions on BBC1. I will feature in the film for a minute or two. Exciting.

For further details see the story in the Guardian.

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. 🙁

special females


Our colour vision results from the fact that our eyes contain three types of light-sensitive cells or cones that have different wavelength sensitivity. Some people (called anomalous trichromats) are colour blind and this is usually because one of their cones is mutated and has a different wavelength sensitivity compared with those in so-called normal observers. Colour-blind is a misnomer really because anomalous trichromats can still see colour; they just have less ability to discriminate between colours than normals. Some people are missing one of the cone classes altogether and are referred to as dichromats; they have even poorer colour discrimination but can still see colour. Only monochromats are really colour blind and they are extremely rare.

For a long time I have known that some females have four cones classes (this makes them tetrachromats). Dr Gabriele Jordan, a researcher at the Institute of Neuroscience (Newcastle University) has spent the last 20 years working on human colour vision. She has discovered that tetrachromatic females exist and that although this gives them the potential for colour discrimination much better than normal trichromats in practice most have normal colour discrimination. However, in a recent report she has found a tetrachromat who really does have enhanced colour discrimination. This is really exciting news!

The report in the Daily Mail suggest that a functional tetrachromat could be able to see 99 million more hues than the average person. Personally I am skeptical of this claim even if, as I suspect, it means 99 million more hues than the average person. The number of colours that an average person can see is debatable but I think may be about 10 million (see my previous blog post).

jaws


“Wearing a light blue wetsuit that matches the colour of the sea will make you less likely to become the victim of a shark attack, according to researchers.
Sharks are completely colour blind and only see things clearly if they are mostly light or dark, scientists have claimed.”according to the Daily Mail.

This does not make a lot of sense – if sharks are colour blind then it wouldn’t matter what colour you wear. But later in the article the point is put better by Professor Nathan Hart, from the University of Western Australia: ‘It’s the high contrast against the water rather than the colour itself which is probably attractive to sharks. So you should wear perhaps more muted colours or colours that match the background in the water better.’

Apparently sharks really are monochromats – so colour blind in the popular understanding of the word – and so it’s really a case of matching the yoru swim suit with the lightness or brightness of the surrounding water. Don’t wear a very bright or a very dark swim suit, in short. Maybe this can lead to better designed swimwear!