The pike and shot era was not a period of standard national uniforms. Bands of mercenaries, and in some rare cases volunteers, would "come as they were when invited" to most battles in the early years of the war. For identification units rallied to their standards, wore the same color scarves (not always the same as the previous battle for the same army) and had distinctive watchwords to be shouted just prior to braining a potential enemy soldier. There were, however, distinctive uniforms in some armies, and common scarf colors.

Pierre Foure informs me that there are known documents which indicate a large purchase of red brown cloth from Venice by Count Tilly to equip his Imperial army, and, as my set of oils has a red brown color called Venetian Red, I assume that it is safe (as safe as most colors) for the Imeprialists. He also mentioned different colors ordered by Gustavus Adolphus from England to equip different units in distinctive uniforms. Col. Dodge, in his book "Gustavus Adolphus," states that the distinctive colors applied only to flags and sometimes scarves, but other sources mention a portrait of Gustavus Adolphus flanked by his officers, backed by their units, each in distinctive colors. Having thus expressed doubt concerning Col. Dodge's facts, it is perhaps inappropriate to quote his colors, but heresay is about all you are likely to get on Thirty Years War Uniforms:

Unit	RegimentFlag and/or Coat color
Ehrenreuter	Red
Vizthum	old(?) Blue
Winkel's	Blue
Hepburn (Scots)	Green
Hamilton (Scots)	Green
Pomeranian	White
Hanse Regiments(3)	Black

Pierre informed me that French units normally had white scarves and plumes. Both he and Blair mentioned the Holkische Jager zu Pferd, a light mounted unit of the Imperialists which wore green coats and red trousers with floppy hats. Imperial cuirassiers in Germany are usually referred to as wearing black armor, though black toned silver shows up better on small scale figures.

If you prefer the English Civil War there is more data available. Norman and Pottinger's History of War and Weapons 449-1600 gives the following coat colors:

Royalists	Parliamentarians
Newcastle White	Lord Brookes Purple
Prince Rupert Blue	Lord Saye's Blue
Royal Guard Red	Hampden's Green East Anglia Red New Model Army Red
The same source gives orange as the Parliamentary, red the Royalist color at Edgehill.

1630 and All That