Depending on the culture and richness of the country. 1400's were time of iron, and weren't that colorful; most of knights wore full plate armors. None nobles were rarely allowed to fight on the European battleground with few exceptions of battle of Grünewald 1410 - were Tatars were allowed to fight.

Full plate armors: The breast plate usually was covered with flannel shirt/over-coat, picturing/coloring of coat of arms of house the knight belonged to. Wooden shields also represented house the knight was from. (Note: Scale armors were quite popular with Polish, until late 1600's, and early 1700's - it was to shown themselves wearing dragon skin, or being dragons - thus more noble family would actually go with scale armor instead of full plate - in late 1500's scale mails were found to be quite musket bulletproof)

The archers or light infantry would wear chainmail with flannel overcoat picturing coat of arms.

So speaking on the actual point of how colorful they were, it depended on the house coat of arms. It was quite common in the Europe (West, South, Central, Partially East)

There are distinctions like Orders such as Teutonic, which worse single white banner with a cross. It was due to way they integrated their members. A noble would have to give up all of his wealth to the order, and title of his lands - thus while coming from noble families they didn't represent them anymore.

There are other distinctions worth noting in terms of helmets. Eastern helmets were usually decorated with feathers of local birds like eagles, storks and pheasant, others. Southern helmets from richer families would use peafowl, to show off their wealth. Though it was rare occurrence that just started to become norm in 1400's.

(1500's brought far more interesting designs and colorfulness)