16-bit or 32-bit color? What is the difference and what should you be using? Its time to share my understanding of color depth in this nerd out session.
First of all, what is a “bit”? The word bit was created from two words, similar to the words blog & vlog. In this case the words binary & digit make up the word bit. Every bit is either a 0 or a 1, off or on. The more bits you have in a string the more possible outcomes you can have. 1 bit has 2 possibilities, 0 or 1. Every time you add a bit to the string the possible number of outcomes double. 1 has 2, 2 has 4, 3 has 8, 4 has 16 and so on.
How does this relate to color? Lets start with 16-bit color which uses 16 bits to define how many colors can be displayed in a single pixel. This is done by using 5 bits for the red channel, 5 bits for the blue channel and 6 bits for the green channel. This gives you 32 possible shades of red and blue and 64 possible shades of green. If you multiply out all of those different possibilities you get 32 x 32 x 64 = 65,536 colors that can be displayed in a single pixel. That is a lot of colors!
Can you now guess what 32 bit color is? Lets dig in. Same concept as 16 bit EXCEPT you get 8 bits per channel. Red gets 8, green gets 8 and blue gets 8. But wait….that only adds up to 24. Where are the other 8 bits? BONUS: A fourth channel with 8 bits is added called the Alpha channel. This is basically a channel for transparency which allows more gradients to the colors. So lets stop and do some math about our possibilities. 1=2, 2=4, 3=8, 4=16, 5=32, 6=64, 7=128 & 8=256. That means 256 possibilities per channel plus another 256 for transparency. 256 x 256 x 256 x 256 = 4,294,967,296 color possibilities. HOLY SMOKES!!!! Over 4 billion color possibilities per pixel!?!? Yes, that’s BILLION with a B. My mind just popped!
So, what are the plusses and minuses of each? Well, 32 bit obviously gives you more options and images can appear more vibrant and smooth (There is something called posterizing that I will have to get into in another blog). The downside? Working in a 32 bit color depth can slow down your computer processing. While 16 bit still has a crazy amount of color combos it may not appear as nice to the eyes. However your computer will process things a bit more quickly. (No pun intended)
My take? If your computer has the horsepower, process in 32 bit. Bigger is better right?
Here is a great article that helped me understand what bits were: http://digital-photography-school.com/16-bit-vs-32-bit-vs-64-bit-what-does-it-all-mean/
Here is a link to another short article that helped me with the differences between color depths: http://www.computerhope.com/issues/ch001557.htm