3D

3D

So you’ve just invested in the latest technology: a 3D TV, but did you know that 3D has been around almost as long as cinema itself. The true name for 3D pictures is stereoscopic. As with sound (you have two ears) we have two eyes so we see from two slightly different points of view and that is translated into 3D by our brains. It has always been easy to shoot in 3D: 2 cameras close together can film the same way as our eyes see. Viewing the pictures is harder though. If you are looking through a “Mattel Viewmaster” which I had as a kid, it’s easy to separate the images as each eye has it’s own eye-piece, like a pair of binoculars. When you are viewing a screen though, it’s a bit harder. In the days of black and white it was easier to separate the images. One image was tinted red and the other green. Then both images were shown on the same screen and you viewed with special glasses with each lens tinted to correspond to the image that the eye was supposed to be seeing – it looked a bit weird if you didn’t have a pair of 3D specs though! Then along came colour and that messed things up. Various ways were tried for colour movies that also used colour as the method to separate the images. That really messed with the whole look of the film though and didn’t really catch on. As technology has improved we have begun to use polarization, as light is a waveform, (explanation of Polarization) but the...
Colour

Colour

Does colour really exist? It’s an interesting question. Different surfaces absorb and reflect different frequencies of light (as light travels in waveforms) and different frequencies are perceived by us as different colours as we have 3 different receptors (cone cells) in our retinas which respond to 3 different ranges of frequency hitting them; red, green and blue. These receptors fire off different signals to our brain which in turn perceive them as colours and thus it can be argued that colours are actually a function of our brains and not the “real” world as much as it can be argued that colour should be spelt without a “U”! The colour digital camera responds in a similar way to the human eye as different sensors are allocated to respond to varying ranges of light frequency. This is done by employing the use of colour filter arrays or by splitting the light entering the camera into its component RGB with the use of a prism. The corresponding sensors then output the level of light hitting them without any actual colour information. It is actually only it’s designation that tells us what colour it is. The information from all three sensors are then combined to give us an overall colour representation. Colour film works in a similar way utilising different layers of a photosensitive salt (a chemical sensitive to light) called silver halide. These crystals are dyed so they are not affected by any other colour than which they have been designated to. Different brands and types of film use layers of emulsion with different types of dye so each type of...
Image Resolution

Image Resolution

Do image resolutions, 1080p, 2K, 4K, cause you confusion? And even if you do know what they stand for, do you wonder why the don’t round up to a neat figure? It all goes back to the early days of computing. A single character was made up of dots called pixels. “Dot matrix” printers would print these out with inked pin strikes on paper. The characters measured 8 pixels across by 8 pixels high which was pretty much the lowest resolution to be able to distinguish numbers from each other. This produced a total pixel count per character of 8 x 8 = 64. That is why all resolutions are actually rounded up to the nearest multiple of 64. Computer memory and storage is measured in exactly the same way. The terms 2K, 4K etc are referring to the number of pixels in the width of the image. K refers to the suffix/prefix Kilo which means 1000. However 2K does not mean exactly 2000. That is because 64 doesn’t divide exactly into 2000 and the nearest rounded up multiple of 64 is 2048. 4k is double that at 4096 pixels but Ultra HD which is incorrectly referred to as 4K is actually slightly less, weighing in at 3840 pixels across. That is because it is twice that of HD which weighs in a little less than 2k at 1920 pixels across. So what is 1080p? Firstly the p refers to the method of image scanning employed (progressive as opposed to interlaced) but that’s another topic. It does indicate however, that the number refers to the height or number of lines in the image rather than the width. In an image...