Hello, I haven't developed film in a long time and I'm getting back into it, but I'm having a hard time figuring out how the ratios work. The developer I plan on getting is Arista liquid film developer. It says to dilute 1 + 9. So, if I have 500ml of water would that be 100 ml of developer and 400 of water? And for the fixer I'm using Arista rapid fixer. it says to dilute 1:4 for film and again with 500 ml of water as an example, 125 ml of fixer and 375 of water? I know the + and the : mean something different. I just want to make sure I'm on the right track.