Hi, I'm wondering why most images are in 16 bit or 32 bit format. Why they are NOT in 11 bit or 29 bit or 138 bit or 397 bit? Can anybody can explain the technical part here? Thanks.
When you are referring to 16 bit images, it means, the colour information of a single pixel (of the image) is represented in 2 power 16 colours. More the bits per pixel in an image, more the number of colours can be produced in an image pixel. Source: http://en.wikipedia.org/wiki/Color_depth As the images are represented in digital format, the bits correspond to a bit in computer world. So, not only 16 and 32 bit images are available but there are also 1 bit, 2 bit and so on. which is explained in detail in the wiki link above. Hope that answers your question. -ishti
Image file "bit depth" depends on what color model is used to describe the color of each pixel. There are many different ways to do this, but for computers and other applications, setting up a standard is important. The more color precision you need for each color in your color model, that is, the larger your gamut of possible colors, the more room it takes to store the color of each pixel. Using a 16-bit color image lets us store a huge possible number of colors conveniently in a file, by letting each byte of 16 bits describe the intensity of a given color channel for a given pixel. That is, you can set each primary color channel of a pixel to one of 65,536 intensities. For each pixel, the combination of the relative intensities for Red, Green, and Blue are described in a set of 16-bit "words". 32-bit images can be used when even more information must be stored for each pixel. This can be better precision (to describe intensities 'between' two 16 bit values), or other factors, such as transparency. Part of the answer to your question is as ishti indicated, you can describe color using completely different color models and you can adapt different file-storage strategies to any of these, but the standards of 16- and 32- bit image files were established to balance the need to display color precisely and the need to transmit or store the data in as small a package as possible. Keep in mind that none of this approaches another important image file characteristic: compression.