If you teach a pupil to read music with coloured notes, will that pupil then find it difficult to read ordinary black notes?
In my own experience, most pupils who have worked through the first book of Rainbow Guitar (or Rainbow Ukulele) will find that they can make the switch to playing tunes with the same notes, printed black in the normal way, within a very short space of time and with very few problems. If you have had a lot of practice in playing tunes which look like this:
then it is not really such a great leap to playing a tune which looks like this:
The fact that pupils can make this transition fairly quickly, and with few problems, is the real proof that this system works. The colours have been helping in the early stages, but they have not been doing all the work! The pupil has still had to learn how the stave works, and to focus constantly on its shapes, lines and spaces.