title: Why use the binary number 64 in base64 as opposed to whole ASCII set?
body: <p>I'm trying to understand why we would use Base64 to convert binary data to ASCII characters rather than just converting it straight to ASCII. In every calculation of Base64 that I've seen, you either start with ASCII characters, or start with binary data which is converted to ASCII in the process of eventually converting it to Base64.</p>
  
  <p><strong>My question is:</strong> Why not just leave it in ASCII, rather than converting it to the Base64 subset?</p>
  
  <p>I've read through all the related questions on Stackoverflow and while I've found lots of useful info, this is the part of the question that I still can't wrap my head around.</p>