Millar painted throughout the first world war, and several of these works survive. He reveals in these paintings an innate facility for composition; that which contributed to the uniqueness of the POP strip and his illustration work.
Time for painting was limited by his own success as a commercial artist. He built himself and his wife a studio in Dedham, Essex, where there was an artisitic community which must have been fascinating; living in the village in the 1920s was Thomas Pyne, whose great-grandfathers had painted with Turner.
Millar became friends with Alfred Munnings and they would drive into the East Anglian countryside sketching and painting together. Willows at Flatford, painted on the day of Millar’s son George’s delivery into the world, was sealed with Munning’s approval : Millar was dabbing distractedly at the water, which is depicted with a minimum of paint, when Munnings suddenly said “Don’t do any more to that!”.
Millar’s paintings - already few and far between, attest to the fact that this was a painter who should have had time for more. His subjects were of Nature at its most fulsome, oak trees of majestic maturity and their deep shade, willows with breeze in their fronds, reflections stamped from bold strokes of bodycolour upon the thinnest canvas washes.
In Polstead Ponds, he paints the flooded ponds with a palette of four colours : viridian, cobalt blue, cobalt violet and white.
He left painting flowers to Amy, however Bouquet is an exception, having been the result of something of a challenge between husband and wife. Millar made a study of the techniques of the great masters and painted this study with oil tempera.
His watercolours and oils were exhibited at the RA for a succession of the years in which he was able to find the time to exhibit. For a variety of reasons, he prefered the provincial art exhibitions and became a member of the St Ives Society of Artists, and it was he who proposed that the Mariner's Chapel should become a permanent home for their exhibitions. He also exhibited with the Ipswich Art Society and his work is represented at Ipswich Museum in a large canvas of rain filled plough at the edge of a field in the Dedham Vale. Somewhere in the world, is a masterful copy of Titian’s Bacchus and Ariadne painted by Millar as a result of his life long study of the technique of the great masters.