John mixes from the developer concentrate. Put packet B into bottle A and shake well. When you want to mix developer, mix the amount that you need using 1 part concentrate to 9 parts water. Following Kodaks instruction wil give you a 1:4 mix as stated above. Remember that Johns reccomendations are only starting points and may not work for everyone. Actually John's current starting point for T-max 100 and T- max RS 1:9 is 11 minutes at 75F, so if you are getting thin negatives at 13 minutes then it is: your mix, thermometer, agitation, shutter, light meter or maybe your water.(posted 8447 days ago)