Ok, I lied, this one is gonna be big and spin your head…
I had planned on starting small and working up to more complex concepts, but then I decided to address bit depth for my first topic. So this first real post is going to give background to the topic and really, there’s a lot that needs to be said here that I will absolutely refer back to.
In conversations about photography, we refer to bit-depth or cameras supporting 12, 14, or even 16-bit raw files. Cameras generally all put out 8-bit JPEGs and TIFFs, so we’re talking about raw files when we talk about bit-depth.
What is bit depth? Well, let’s start with a description of what every one of us see on a daily basis: 8 bits.
Every computer/tv screen you see is optimized for 8 bits per channel, in the sRGB color space. 8 bits describes 256 colors, or black through the brightest of that color. Like so:
This “ramp” of green has a total of 255 values of green and one value for true black. Each “pixel” on your computer screen has three sub pixels of red, green, and blue, and each gets assigned one of these values. Black gets a value so that each sub pixel can be completely off.
Why is this important? Because the human eye can barely distinguish between value 255 and 254 on this ramp. Really, here they are, try it:
Can you see a difference? Can you see which part of this patch is 254 and which is 255? Unless your monitor is severely broken or improperly calibrated, no, you will not see the division between the two colors very clearly. Why is this important? Well, to illustrate what bit depth means. If the above ramp were 16 bits of green, you wouldn’t get a brighter green or darker black, you’d just get the same range of values chopped up into finer “bits”. A total of 65536 values to be precise.
Why on earth would you want that precision? Read on…
