What Happens to All Those Data Bits

If 12, 14, and even16 bits per primary color sounds like an awful lot of data to you, you're right. It is. (See Table 1-1.)

If left intact, all those data bits would inflate image file size and considerably slow down in-camera processing. And it wouldn't really be of much benefit when you view the pictures. The human eye is capable of discerning approximately 12 million different colors, which is why 8-bit color is considered photo-realistic. What's more, only a handful of image-editing programs, like Photoshop, have the ability to work with image files larger than 8 bits. Even if you are able to work in 12-bit or 16-bit color, you can't really output it in that form because there isn't a desktop printer made that can use anything other than 8-bit color.

Table 1-1 How Much Data Is in Those Bits?

Bits Formula for # of Colors in RGB Total Possible Colors

8 bits 256 x 256 x 256 16.7 million

10 bits 1024 x 1024 x 1024 1.07 billion

12 bits 4096 x 4096 x 4096 6.87 billion

14 bits 16380 x 16380 x 16380 4.39 trillion

16 bits 65536 x 65536 x 65536 281.47 trillion

So what happens to those extra bits? They get thrown away, in a process called sampling. You are probably thinking: why the heck should a digital camera collect all those data bits if they're only going to be discarded? That's where the camera's smarts come into play. The camera's image processing includes examining all the captured bits, and by using mathematical formulae developed by the manufacturer's engineers, deciding which set of data bits will produce the best image. Some cameras have built-in stored profiles to which they compare the just-shot image, looking for similar pictures and then selecting the best bit set. Professionals and experienced hobbyists who don't want a camera making that decision for them will shoot in RAW file format, which keeps all the bits intact until the photographer can view them in special software in the computer and choose how they should be processed. (See Chapter 5 to learn more about RAW)

Learn Photoshop Now

Learn Photoshop Now

This first volume will guide you through the basics of Photoshop. Well start at the beginning and slowly be working our way through to the more advanced stuff but dont worry its all aimed at the total newbie.

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  • Ensio
    What happens in photoediting?
    8 years ago

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