Oak (Quercus spp.) was used in the construction of the panel and its altarpiece.

The preparatory layers consist of a single white ground mainly composed of anhydrite with small amounts of calcium sulphate. A concentration of organic material is observed on the top of the ground but no clear separate  intermediate layer is visible.

The palette is composed of lead white, carbon black, lead-tin yellow oxyde type I, vermilion, ochres, azurite, smalt, verdigris and a red lake made of cochineal and Brazilwwod.

Colours were formulated using straightforward pigment mixtures. Generally one colour, mostly originating from a single pigment was shaded with black and/or ochre and lightened with lead white.

The technique is fairly simple with most of the samples showing a succession of one of two layers of paint over the preparatory layers. The use of three superimposed layers corresponds to the draperies glazed in red and green.  Local underpaints were found beneath the blue mantle of the Virgin, a technique that is commonly found in paintings of this period, notably Portuguese.
The painter created colour not only through pigment mixtures and paint build-up but with a palpable handling of the paint when it was still fresh.

The degradation of paints rich in smalt and verdigris has caused a dramatic and irreversible change in the colour balance of these paintings.  Beyond the presumed original blue colour of the skies of the predela paintings, the pigment deterioration has especially affected the central figure of the Angel in the Annunciation. Although it is impossible to accurately determine the original colour of the paints, where an almost "black and white" angel is now observed, a much more nuanced and brilliant blue, pink and purplish tunic and wings would have richly combined with a saturated and vivid green cape lying over the Angel's left arm. These vibrant and diverse colours would have framed the central yellow raising arm of the Angel, imparting him a celestial glorious status that is now obscured.