Paint
Paint was used during our period but to what extent is not fully understood. The volume of extant woodwork finds makes recreating actual artefacts difficult without considering whether they were then painted, and if painted then how and in what style.
Making paint
All paint is made from a pigment and a binder. This was no different in the dark ages, however, many surviving paint making recipes are for ‘artist’s paint’, generally for highlighting manuscripts and the like, and these paints are unlikely to be suitable for general woodwork and other decorations.
Pigments could be derived from natural earth metals and the like, such as yellow from ochre, or greens from copper salts. Others like black could be made from charcoal or soot. The range of colours available does seem relatively large, but almost all colours are subdued even dull to the modern eye. There are no really bright colours ; even pure white was not available. Dull or off-white could be made from burnt lime and was used as whitewash for buildings.
For an example range of period colours see http://www.milkpaint.com/color.html Binders could be egg yolk (tempera) and/or milk (casein), but it is very questionable as to whether such paints would remain weatherproof. Oil base binders were probably also used. Turpentine could be produced by heating pine trees over a collecting pit, and know that turps based paints were used on ships because turps was used to thin out tar as a protective coating to ship timbers. Similarly linseed oil is a traditional paint binder, and which considering the production of linen should have been available.
Due to the process required to make paint, it was probably a fairly expensive, and the expense might well have restricted its use. It is also quite possible that the availability of local resources might have made one colour cheaper in a particular area, whilst other colours were either not available or had to be imported.
Credits: with thanks to Steve Lines.