Some more info from James on the decoration of the Dura shields:
At least three media used for paints and preparation:
The Yale rectangular shield was painted with encaustic. Good for weatherproofing.
The oval shields mostly prepared with gesso to take paint, of tempera, and one casein.
Various pigments and dyes probably identified; vermilion, carbon black and a reddish yellow earth. Indigo extensively used.
Basic technique was to apply an overall base colour, usually red, to the gesso or skin covering
(not under the skin), then overlay the detailed decoration.
The design on shield 629
(the famous cylindrical one) could well be legionary in character.
The important thing that strikes me is the number of Dura shields with paintwork on: 629, 616, 617, 621, 622, 624, 618, 633, 634, 629, 633, 634.
He does ask the question if the decorated shields are for parade, and goes on to say that soldiers may have had two shields for combat and parade. He suggests the more uncomplicated designs were for combat roles, but the surprising thing is he puts the famous semicylindrical shield (629) in that category.
hock:
He does believe the shields with dominant single figures of could be unit specific and for parade.
"Shield 629 even corresponds with Polybius' description of of the facing technique, with fabric first, then skin (contra Rep,. VI, 461). Masada has yielded a fragment of a shield faced with a layer of textile covered with a red-pigmented leather,..."
Shield 629 is of plane wood, and the plank shields of poplar, corresponding with Pliny's observations on the best woods for shields (woods that heal together at once and close up their own wound - vine, agnus castus, willow, lime, birch, elder and both kinds of poplar. Plane has flexibility, but of a moist kind, like alder; a drier flexibility belongs to elm, ash, mulberry and cherry, but it is heavier...)
The surprising introduction of simple plank shields, and he thinks it was for making convex shield boards which may have outweighed the advantages of plywood. The fibre facing layers would have offset splitting, so there is no reason to believe they were only for ceremonial or training use. Fragments were found in the 'combat deposit' of Tower 19.
Similar shields found elsewhere from Egypt to Trier.
Masada produced shield leathers from oval shields, possibly Republican scutum shape, and plywood board fragments with traces of gesso, fabric and leather, some with traces of reddish and bluish paint.
Going back to the shield I posted earlier, "It is virtually certain that the oval plank shields were used in the fighting. They are the predominant type at Dura, and parts of one or more were found in the Tower 19 countermine with the the bodies... It may be that the painted shields discarded under the rampart were regarded as valueless for fighting not because they were made of planks, but because they lacked the 'anti-split' layers of fibre/glue and skin covering."
So, the shield I posted (616) looks like it probably was decorative. The scene is also said to be the Trojan War.
dagga...dagga...dagga..."ugh". I take it all back and am eating my own words.