[Formendacil]

Perhaps, Master Narfforc, the reason of colour lies within the context of each Istar's role within Middle-Earth, rather than any particular choice of their own.

We know, by the very fact that Gandalf the White- by virtue of being "the White"- superceded Saruman the White- and replaced him as Head of the Istari in Middle-Earth, that the colours associated with the Istari had to do with their roles in Middle-Earth.

However, there is no reason to assume that the colours had to do with rank, as such.

The role of Saruman, the role later assumed by Gandalf, was to lead the Istari, and by connection, to lead the entire West in battle against Sauron. The suitability of White to this role can be seen in the complete and utter contrast between White and Black- and note that Black is always associated with the Dark (think Black) Land: Mordor (mor- meaning black/dark), Barad-dur (-dur meaning black/dark), the Black Land, and more.

Gandalf, we know, was sent to Middle-Earth, it seems, with the role of inspiring courage and giving counsel, and generally roaming around being helpful. He is, in other words, a behind-the-scenes sort of person. And grey, as a background colour, is quite suitable to this role. Or, possibly, Grey could be a sign of the portions of Middle-Earth to which he was sent. He seems to have been especially concerned with Eriador, and somewhat less to the lands about: Gondor, Rhovannion, Wilderland in General. In these lands, there is a very strong feeling of nostalgia, particularly amongst the Dunedain and Eldar. And grey is a colour that is well-suited to people who are nostalgic, since the colour of life is for them in the past. It seems clear that Gandalf spent the most time of the Istari amongst the Eldar of any kind, but also among the Northern Dunedain, and he shares the distinction, or so it seems, among the people of Gondor. With either of these suppositions, it's possible to find a possible reasoning for the colour in Gandalf's particular mission.

Radagast's particular mission is, of course, obscure. However, by reason of his love for animals (birds, in particular), as well as his association with Yavanna, it doesn't seem outlandish to suggest that it may have been his task to rally the natural forces of Middle-Earth against Sauron. To a mission such as this, Brown seems an eminently suitable colour, brown being a colour found in many shades in nature, among both animals and plants, and is evocative of a richly fertile earth.

This leaves Alatar and Pallando, the two wizards known as "the Blue". Their mission seems plain enough: they were sent into the East, presumably to rally the people there against Sauron, and whether or not they failed is completely obscure. The reasoning for Blue for such a task is not quite so obscure, but obscure enough. Perhaps blue was meant to signify the Sea, which may not have been familiar to the Men of the East, but which in Middle-Earth tends to signify the West, and by connection good in general. Perhaps such a connection to the West and to Good was more needed in the dark East than anywhere else. Similarly, it may just refer to water, which- thanks to Ulmo- was always a connection to the Valar and the West. Another theory that pops into my mind is that it may have had to do with the clear blue sky, which would have been nature's greatest contrast to the dark nights with which Sauron would be identified. Whatever the Blue was intended to represent or signify, however, the fact that both Alatar and Pallando wore it, and the fact that both of them went on the same mission, makes it heavily supportive of the idea that the colours of the Istari signified their missions- not their ranks.

As to any suitability that may be found between character and colour, that can be explained in that each colour was suited to each task, and each Istar chosen for his suitability to the task. One will note that Manwe and Varda considered Gandalf as "Not the Third". That he was not sent to lead the Istari does not necessarily mean, although it seems implied, that he was weaker than Saruman, so much as it means that Saruman was more suited to that task while he, Gandalf, was more suited to the task to which he was set.