Convert RGB/HEX etc to paint formula
I have to question this.....Why do you even want to mess around with this? There are a few really good reasons that show that this makes no sense.

1) When you go to buy paint at your supplier (hardware store, big box or paint store) there is generally little or no difference in price of the paint whether you buy the straight white in the can or have it colorized to your choice. You can even bring in a sample at most outlets these days and they will mix to match. 

2) If you want to use your machine you have to pay separately for any tints / colorizers that you would use. 

3) These machines can be a real mess if things leak or break. 

4) I believe that these machines require regular maintenance that becomes even more important if there is not a minimal amount of usage of each colorizer dispenser. 

Based upon these factors I would have to suggest that it makes no economic sense even start with this.