Wednesday, 21 January 2009

Sharpening and blurring

Sharpening a photo is the opposite of blurring and both can be done on a computer. A sharpened photo looks like it has more detail, but too much sharpening make it look grainy. This is a term borrowed from conventional photography when you could see clumps of silver halide grains in the prints. However with digital photography if you can see the individual pixels it is called noise and if it is really obvious it is pixelation. You may have seen the occasional pixelation of your TV screen.

Sharpening is needed because digital cameras are not perfect and there will be a little blurring with each photo. However a badly out of focus photo cannot be rescued by the computer.

The opposite of sharpening is blurring. Soft focus photos are those which allow some blurring but there is still some sharpness about them. This blurring means that you don't see skin imperfections and is often used for portraits. However there are lots of other techniques that get rid of blemishes and don't cause blurring but I'll write about these at a later date.

I remember seeing a film which I think was from the 60s in which a photo was enlarged and enlarged again so that the date on a newspaper could be seen. This technique was possible with an expensive photographic studio and state of the art equipment. Now anyone can replicate this technique with a home computer. Just keep enlarging the photo but if you really want to see that date then sharpening may come in useful.

Happy snapping

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