Ok, When I said I wouldn't have to explain binary numbers and how the computer counts ,,, I lied.

Below is my quick and dirty binary number explanation. Very quick and very dirty. I've included some links to other web sites at the bottom of this page that may explain better.

The confusion is that the computer doesn't use the standard base 10 number system. The computer only uses the numbers 0 and 1. It counts in the base(2) or binary system.

This is a complicated topic but I'll try to be brief.

Remember back to when you learned to count numbers. The number 1251 was taught as 1 in the 1's column 5 in the 10's column 2 in the 100's column 1 in the 1000's column -------------------------- 1+50+200+1000 = 1251 This is called the Base(10) system because each column is 10 times greater than the last Read numbers in the Binary, Base(2) system in the same maner Read the number from RIGHT to LEFT. The first column is the number of 1's The second column is the number of 2's The third column is the number of 4's The fouth column us the number of 8's Etc, Etc Each column is 2 times greater than the last. 8's 4's 2's 1's So the binary number 1011 would be 1 in the 1's 1 in the 2's 0 in the 4's 1 in the 8's or 1+2+0+8 = 11 in base(10) Here are the numbers 1-10 in Base(10) and Base(2) Base Base 10 2 ---------------- 0 0 1 1 2 01 3 11 4 100 5 101 6 110 7 111 8 1000 9 1001 10 1010 Another way to look at this data is to assume that you have an 8 bit number, then determine how high can you count using this many bits of data. # of bits Example Base 10 ------------------------------------------------------------- 1 1 1 2 11 3 4 1111 15 8 11111111 255 16 11111111 11111111 65,535 24 11111111 11111111 11111111 16,777,215 This chart is more commonly shown as below, where the number zero is included in the total. The number of bits is called the "Bit Depth". Bit Total Depth Numbers ------------------ 1 1 2 4 4 16 8 256 16 65,536 24 16,777,215 32 4,294,967,296The only special case is the TIFF file which can be stored as a 32 bit color file. This is not a file with 4 billion colors. Rather it is a file with 16 million colors and each pixel has a 8 bit number added to show 256 variations of transparency. This is called the Alpha channel.

For More detailed information

Binary Number Tutorial

Binary Number Systems