== Key coloration == 

 I think this section needs amendment.  

 Pythagorean tuning is a bad example for a tuning with key coloring, meantone tunings would be equally bad examples. When we look at the interval structure of those keys, we notice that all keys used in the historical periods related to those tunings had exactly same interval structure in each of the keys. The drawback to this uniformity is the presence of wolf tones, which prevent one from modulating around the whole circle of fifths. Thus, the fact that renaissance keyboards had twelve keys to an octave does not imply that the chain of fifths was viewed as a circle. 
 The two ways to accommodate for these wolf tones were simply retuning the instrument, or far less commonly, instruments with split black keys, one producing the flat note, another the respective sharp note. 

 The 18th century solution to this, was using microtonal variations of the same interval in a way that eliminated wolf tones. The side effect of this microtonal variation was that each key sounded a bit different. That is my understanding of what key coloration usually means. Equal temperament is a later invention that allows modulation around the whole circle of fifths without any key coloration. 

 My position is that even though wolf tones are here cited as examples of key coloration, they are applicable to that purpose only from the viewpoint of modern music, in a somewhat rebellious spirit. They are however not examples of key coloration in the theoretically more conservative sense of the word.