Am I right that 255 is all eight binary values (0-7) converted to decimal again?
No, 255 is all eight bits of a byte set to 1:
255 == 0b11111111
If you have a binary number abcdefgh, where a-h are all either 0 or 1, you can convert this to a decimal value using the following:
value = a2^7 + b2^6 + c2^5 + d2^4 + e2^3 + f2^2 + g2^1 + h2^0
= 128a + 64b + 32c + 16d + 8e + 4f + 2g + h
Note that you can perform this exact same calculation in a base-10 system (there's nothing special about base-2). For example:
1234 = 1 * 10^3 + 210 ^2 + 310^1 + 410^0
= 11000 + 2100 + 310 + 4
For a general base b, your numerical value is:
sum from i = 0 to n-1 of (digit i * base ^ i)
where you have n base-b digits in your number.
Does this make sense?
- Ben