glblanchard wrote:
Seriously? You guys understand all this? I'm depressed.
well how many different reds blues and greens can you see? more than 2 levels of red or 4 or 8 ? well some clever people figured out 256 levels was more than we can see in red green or blue. our eyes are more sensitive to some colours than others but we can't see any colour in more than 256 levels
it could be just 200 but 256 is useful. computers work with bytes groups of 8 bits and counting in binary is just like decimal with less digits 2 to be exact so 0, 1 , 1 0, 11 is the same as 0, 1,2, 3 in decimal. binary numbers get very long and hard to see the value of for us. so we need a shorthand and hexadecimal does that its a base 16 number system and goes 0123456789ABCDEF we use A-F because we havent symbols for those higher digits and we also know that B is higher than A but less than C
a single hex digit is enough to hold 4 binary digits from 0000 to 1111
a byte is 8 bits so two hex digits can represent 00000000 to 11111111
in binary, in decimal thats 0 - 255 that gets hard to convert to binary
but
0000 0
0001 1
....
1111 F
is fairly easy
F110 is 1111 0001 0001 0000 in binary
you just group the binary into groups of 4. (F110 is a 16 bit number or 2 bytes).
any way to write a number to represent any colour we can see can be done with 00,00,00 to ff,ff,ff. the first pair says how much red the next how much green and the next how much blue. so 00 66 00 s going to be some shade of green... 66 66 66 is a gray as no colour dominates 66 66 99 would be a bluey gray. thats another problem we don't have 24 million names for colours so these numbers are the best we can do.
Computer generally doesnt care if a colour is written as a decimal value or a hex value as both get converted to binary but if i write 66, 66, 66. as a colour value you don't know if that is in hexadecimal or decimal this number is higher in hex than in decimal a different colour depending on which base is being used. so hex is used as a rule to write colour values.
to finish on a question what value is 18% gray?