Have you ever hear of Tomatoes Colour Chart?

Green

   The tomato surface is completely green. The shade of green may vary from                         light to dark 

 Breaks

    There is a definite break of colour from green to bruised fruit. Tannish-                                  yellow, pink or red on 10% or less of the tomato surface.

 Turning

      Tannish-yellow, pink or red colour shows on over 10% but not more than                             30% of the tomato surface.

 Pink

      Pink or red colour shows on over 30% but not more than 90% of the tomato                         surface.

 Light Red

      Pinkish-red or red colour shows on over 60% but red colour covers not                               more than 90% of the tomato surface.

 Red

       Red colour shows on over 90% of the tomato surface. Due to varying                                   screen resolutions, the accuracy of this colour chart cannot be relied                                   upon.

Source