These two methods set distinct limits to the work and its effects. The colors were ground up day by day in the shop. Each had its little pot. There was no palette. Hence only a few colors were used, and with little mixing. For tempera painting a good wooden panel—preferably of poplar—was grounded with successive coats of finest plaster of Paris in glue and rubbed down to ivory smoothness. The composition was then copied in minutely from a working drawing. The gold background inherited from the workers in mosaic was laid on in pure leaf. The composition was first lightly shaded and modelled either in green or brown earth, and then finished up a bit at a time, in colors tempered with egg or vegetable albumen. The paints were thick and could not be swiftly manipulated; the whole surface set and so hardened that retouching was difficult. How so niggling a method produced so broad and harmonious effects will seem a mystery to the modern artist. It was due to system and sacrifice. Though the work was done piecemeal, everything was thought out in advance. Dark shadows and accidents of lighting which would mar the general blond effect were ignored. The beauty desired was not that of nature, but that of enamels and semi-precious stones. These panels are glorious in azures, cinnabars, crimsons, emerald-greens, and whites partaking of all of these hues. Their delicacy is enhanced by carved frames, at this moment, 1300, simply gabled and moulded; later built up and arched and fretted with the most fantastic gothic features.