www.rugbyfootballhistory.com/allblacks.html
This is very interesting on how the name came about, given to them by the English Press!
The New Zealand test side was not always called the All Blacks, (in the early days they were called Maorilanders, the New Zealanders or even the Colonials), they were given that name during their famous 1905 tour to the British Isles, France and Canada.
The 1884 side mentioned above had for its uniform a dark blue jersey with a gold fernleaf over the left breast, dark knickerbockers, and stockings. It was certainly not ?All Black?.
After the formation of the New Zealand Rugby Union in 1892, it was resolved that the New Zealand representative colours should be ??Black Jersey with Silver Fernleaf, Black Cap with Silver Monogram, White Knickerbockers and Black Stockings?? on the motion of Mr WEllison and seconded by Mr King. This was the standard uniform for some years, though photographs of the 1894 and 1896 teams show that white shorts, and not knickerbockers, were worn. There is no photograph of the 1897 team in uniform?in the official photograph they are shown wearing long trousers?but in the New Zealand Graphic of 14 August 1897 there is a cartoon of a New Zealand footballer wearing a black jersey and white shorts.
For the 1905 tour the shorts were changed to black.
The "Express & Echo in Devon appears to be the first to use the term All-blacks when it recorded the day the 1905 touring side beat Devon 55-4 in their first game, "The All Blacks, as they are styled by reason of their sable and unrelieved costume, were under the guideance of their captain (Mr Gallaher), and their fine physique favorably impressed the spectators".
By 11 October the Daily Mail by Buttery, had also picked this up and reference ?All Black? play and its complement, ?All Black Cameraderie?. From then on the new name gradually won acceptance, so much so that by early November, following the match with Surrey (1 November), the Daily Mail made direct mention of the All Black team ?that everybody is talking about?.