Resolution and Colour Depth

Resolution and Colour Depth

The resolution of an image determines how many pixels the image has. It is usually expressed by stating the how many pixels there are horizontally and how many there are vertically e.g. 200 x 100. This means there are 200 pixels horizontally and 100 pixels vertically and this can be used to calculate the total number of pixels in the image: 200 x 100 = 20000. The resolution of an image is very important because the more pixels there are, the more detail there is in the picture. For example, printing a picture of 200 x 100 on a A4 sheet would be smaller and of less quality than that of a picture 2000 x 1000.

Colour depth is the number of colours that can be reproduced in an image. Pictures with low colour depth will be able to produce less colours than that of a picture with high colour depth. For example, 8-bit colour has 256 colours while a 24-bit colour image has 16,777,216 colours in its palette. High colour depths produce higher quality but very large file size because the code for each colour is longer. Deep colour images are that of very high colour depths such as 48 bit which can produce 285.1 trillion colours. These file sizes are very large because each colour code is 48 bits long.

The disadvantage of using very high colour depth is that it will make the file size a lot larger since each pixel requires more data. This means that high resolution pictures with high colour depth will be extremely large and slower computers will have trouble displaying and editing these pictures. Also, older computers will not even be able to display high colour depths so the the file size will be unnecessarily large. Also, on most pictures, having a very high colour depth will not make much of a difference in the final image.

Since colour depth allows more colours to be displayed, pictures can look a lot more vibrant and full of life as in the picture above. It also adds more levels of realism to photos since photos will low colour depth will not look realistic due to the lack of smoothness in gradients. Picture will also be easy on the eye and will not suffer from bad colour variation as in the red of the 8-bit version above. In the 24-bit colour depth version, the red is very smooth and vibrant.