Category Archives: technology

Has technology for Harry Potter’s Daily Prophet just arrived?

I believe that print as we know it is dead. I know that there are some arguing that print is having a resurgence – just as there are those who think that vinyl is on the way back for music – but reports that physical books are gaining ground at the expense of digital are just plain wrong as is explained in this article. I saw this before with digital images where people argued that digital images would never replace traditional photography because of quality and price. Well, of course, we know that the quality of digital images increased and the cost of getting them decreased (when I was a student in the 80s it would have been bizarre to imagine that everyone would have a couple of cameras on them at all times) – but it was not this that killed traditional photography and eventually put the giant Kodak out of business. What killed traditional photography was when you could go to a gig, take a photo, and share it almost instantly with your friends around the world. Traditional photography could never compete with this.

Some people prefer reading print to looking at a screen though I am not one of them. But imagine when an e-document feels like paper, is light and flexible, but you can carry a whole newspaper with you (not to mention all the novels you have ever read) by carrying just one piece of it. And it looks just like print.

E ink, the company behind the pigment-based, low-energy monochromatic displays found in many of today’s popular readers has worked out how to create up to 32,000 colours using almost the same technology. For the first time they can create colours at each pixel using yellow, cyan, magenta and white pigments. The new display is 20-inch with 2500 x 1600 resolution. The image below is rendered in this way. This leads to the possibility of having coloured moving images made out of ink – just like the Daily Prophet in the Harry Potter movies. Well, not quite like that yet. But it’s coming. More details here.


light that changes colour with your mood


The future of lighting is LEDs and that means more colour. There are many advantages of LED lighting over tungsten or even fluorescent lights not least of which is the opportunity for more colour. I have noticed all of the new buildings on the campus at the University of Leeds are equipped with coloured lighting. The Laidlaw library – and even the new car park – is illuminated at night in an eerie purple glow.

The Syska SmartLight plugs into a standard socket but then can be controlled using the “Syska Rainbow LED” app for your Android or iOS phone or tablet.

I want one. But I am not sure they are on sale in the UK. More details here.

RGB displays are more complicated than you think


Most people assume that display screens are based on RGB – that is the amount of red, green and blue light emitted is controlled in three signals. We tend to think that there is an RGB ‘value’ at each pixel. However, the reality is a bit more complicated. The picture above is a close up of the sort of display on the Samsung Galaxy S phones, as well as the Nexus One. It is called an RGBG pentile layout. This layout was introduced because our eyes are more sensitive to green light (so green pixels don’t need to be as physically large to appear just as bright to our eyes). However, it means that the ‘pixel’ in a standard AMOLED display consists of 8 colours: RGBG on top of BGRG. Some people claim this leads to less sharp images compared to the standard RGB displays of LCD displays (see below) that are sometimes referred to as real-stripe displays.


Some of the AMOLED displays have an RGBW layout, which adds a white subpixel next to the standard RGB subpixels. This allows the display to have an edge in brightness due to a dedicated white subpixel. With that advantage the backlight doesn’t need to be as bright, which saves battery since the backlight is a major user of battery in a mobile device. There is also Samsung’s latest Super AMOLED display technology that has a new subpixel arrangement called the Diamond Pixel. The first phone to use this pentile type was the Galaxy S4. There there are twice as many green subpixels as there are blue and red ones, and the green subpixels are oval and small while the red and blue ones are diamond-shaped and larger (the blue subpixel is slightly larger than the red one).

Displays are much more complicated and varied than you might think. One consequence is that it is not so easy to compare the resolution of different displays technologies beacause they vary in what they call a pixel.

do glasses for colour blindness work?


For a while there have been coloured lenses on the market that claim that to make colour blindness better. I have my doubts about this. I have tested some of these glasses in my own research and found that they do not work. So I was interested to hear of work by Rebecca Mastey and Richard Schultz at University of Wisconsin-Green Bay that also finds that the products do not work. The researchers tested products from with 27 men with genetically confirmed red-green colour blindness.

The O2 Amp glasses showed some improvement with deuteranomalous observers and deuteranopes, no improvement was found for protonopes whilst the EnChroma glasses had no significant impact on the red-green colour discrimination of any of the participants. The work was presented at the annual meeting of the Association for Research in Vision and Ophthalmology in Seattle.

“The data confirm that these glasses don’t work,” says Dr. Carroll. “In fact, they make some aspects of your vision worse.”

Out of interest, there is also this personal story about a guy with anomalous trichromacy who tested some glasses from EnChroma and fond they made no difference at all.

The future of colour is quantum


Although our digital displays can show literally millions of colours in fact they show us less than half of the possible colours in the world. This is partly because of the reliance on trichromatic devices – what you probably know as RGB. No matter how we choose them, it is impossible to mix together three colours and make all of the other colours. This is despite this embarrassing statement on the BBC website:

Red, yellow and blue are primary colours, which means they can’t be mixed using any other colours. In theory, all other colours can be mixed from these three colours.

This is just plain wrong. It is not the case that in theory, all other colours can be mixed from these three colours. In theory, and in practice, they cannot.

But I digress. The point is that using a three-colour primary system – a trichromatic system – is never going be able to reproduce all of the possible colours in the world. But even if we do use three, we could do better than the current TVs, phones and tablets on the market if we could improve our technology. The problem is that the red, green and blue lights in these displays are not as bright and colourful as they could be. That is where quantum dots come in.

Quantum dots are tiny crystals that can be precisely tuned to efficiently produce very specific colours. The crystals are grown from a mixture of various semiconductor materials and liquid solvents. By carefully controlling the conditions, engineers can adjust the size of the crystals, which determines the wavelength of the light that the crystals emit. Smaller quantum dots, with a diameter of two nanometres (two billionths of a metre) or so, emit short-wavelength, or blue, light. Bigger dots, with diameters closer to eight nanometres, produce light that’s nearer the long-wavelength, or red, end of the spectrum. We can expect to see new technology on the market soon offering brighter and more colourful displays.

green light may cure your headache

I get migraines. Not often. Just a few times each year. But when I get one I have been known to turn off the lights and go to sleep in my office. I have found that taking a pain killer and then going to sleep is the only way to relieve my symptoms. But a study in the journal Brain suggests that exposure to green light actually has a beneficial effect.


In the study 80 percent of subjects reported intensification of headache with exposure to high intensity of light, except green. Surprisingly, the researchers found that exposure to green light reduced pain 20 percent. They also found that the signals generated in the retina for green light are smaller than those signals generated for red and blue light. Researchers are now trying to develop a more affordable light bulb that emits pure narrow-band wavelength of green light and sunglasses that can block out all colours of light except narrow-band green light.

clothes that change colour

Colour-shifting threads that change their hues in response to electrical charges are being developed as part of Google’s Project Jacquard. The technology still has a way to go before it could be in the shops but it gives the potential that your could change the colour of your clothes with the ‘flick of a switch’ rather than buying new ones or even that clothes could change colour with your mood. As if that would be a good thing.

For more see here.

measure colour with your smartphone


This looks interesting. Node is a way to add sensors to your iOS device. It allows you to measure all sorts of things, including colour if you have the node+chroma combination. The node costs about £100 and the additional sensors cost about £50 each. I am not sure how much the chroma sensor costs.

You can find further details here –

accurate colour on a smartphone or tablet

Electronic displays can vary in their characteristics. Although almost all are based on RGB, in fact the RGB primaries in the display can vary greatly from one manufacturer to another. Colour management is the process of making adjustments to an image so that colour fidelity will be preserved. In conventional displays – desktops and laptops – the way this is achieved is through ICC colour profiles. Colour profiles store information about the colours on a particular device that are produced by RGB values on that device. So to make a display profile you normally need to display some colours on the screen and measure the CIE XYZ values of those colours; you then have the RGB values you used and the XYZ values that resulted. The profiling software can use these corresponding RGB and XYZ values to build a colour profile so that the colour management engine knows how to adjust the RGB values of an image so that the colours are displayed properly. Building a profile often requires specialist colour measurement equipment – though this can often be quite inexpensive now. If you are using your desktop or laptop display and you have never built a profile then you are probably using the default profile that was provided when your display was shipped. The default profile will ensure some level of colour fidelity but particular settings (such as the colour temperature or the gamma) may not be adequately accounted for. If you want accurate colour then you should learn about colour profiling.

It all sounds simple except for the fact that ICC colour profiles are not supported by iOS or Android operating systems on mobile devices. I find this really surprising but that’s how it is for now. Maybe it will be different in the future.

This means that ensuring colour fidelity on a smartphone or tablet is not so straight forward. So what can you do?

Well, there are two commercial solutions to this problem that I am aware of. They are X-rite’s ColorTrue and Datacolor’s SpyderGallery. ColorTrue and SpyderGallery are apps that will use a colour profile and provide good colour fidelity. These are great solutions. Perhaps the only drawback is that the colour correction only applies to images that are viewed from within the app. Having said that, they allow your standard photo album photos to be accessed – but the correction would not apply, for example, to images viewed using your web browser. This is why a proper system implemented at the level of the operating system would be better, in my opinion.

There are two alternatives. The first would be to implement your own colour correction and modify the images offline before sending them to the device. This would not suit everyone – the average consumer who just wanted to look at their photos for example. But it is what I typically do here in the lab if I want to display some accurate colour images on a tablet. But if you were a company and you wanted to display images of some products for example – it might be a reasonable approach. It has the advantage that the colour correction will work when viewed in any app on the device because the colour correction has been applied at the image level rather than the app level. But it does mean you need to do this separately for each device and keep track of which images are paired to each device. This is ok if you have one or a small number of devices but maybe not so good if you have hundreds of devices.

The second alternative would be to build your own app. If you want to do things with your images that you cannot do in ColorTrue or SpyderGallery or if you have lots of devices and you can’t be bothered to manually convert the images for each device, then you could install your own app that implements a colour profile and then does whatever else you want it to do.