The mixture of colours appears to have been reduced to a perfect system, each hue having others specially adapted and used, for heightening and lowering the pure tint; thus the author gives directions which are likely to be scarcely less useful to the illuminator of the present day than they were to those of old.
Of Mixtures.
"If, therefore, you should desire to know the natures and mixtures of these [the above given] colours, and which are antagonistic to each other, lend your ear diligently.
"Mix azure with white lead, lower with indigo, heighten with white lead. Pure vermilion you may lower with brown or with dragon's blood, and heighten with orpiment. Mix vermilion with white lead, and make the colour which is called Rosa, lower it with vermilion, heighten it with white lead. Item, you may make a colour with dragon's blood and orpiment, which you may lower with brown, and heighten with orpiment. Yellow ochre you may lower with brown, and heighten with red lead (query, with white). Item, you may make Rosam[[110]] of yellow ochre and white lead, deepen with yellow ochre, heighten with white lead. Reddish purple (folium) may be lowered with brown, and heightened with white lead. Item, mix folium with white lead, lower with folium, and heighten with white lead. Orpiment may be lowered with vermilion, but cannot be heightened, because it stains all other colours."
Of Tempering.
"Greek green you will temper with acid, deepen with black, and heighten with white, made from stag's horn (ivory black). Mix green with white lead, deepen with pure green, and heighten with white lead. Greenish blue, deepen with green, heighten with white lead. Yellow, deepen with vermilion, heighten with white lead. Indigo, deepen with black, heighten with azure. Item, mix indigo with white, deepen with azure, heighten with white lead. Brown, deepen with black, heighten with red lead. Item, make of brown and white lead a drab (Rosam), lower with brown, heighten with white lead. Item, mix yellow with white lead, lower with yellow, heighten with white lead. Lower red lead with brown, heighten with white lead. Item, red lead with brown, deepen with black, heighten with red lead. Item, you may make flesh-colour of red lead and white, lower with vermilion, heighten with white lead."
Which Colours are Antagonistic.
"If you wish to know in what manner colours are antagonistic, this is it. Orpiment (sulphuret of arsenic) does not agree with purple (folio), nor with green (acetate of copper), nor with red lead, nor white lead. Green does not agree with purple.[[111]]
"If you wish to make grounds, make a fine rose-colour of vermilion and white. Item, make a ground of purple mixed with chalk. Item, make a ground of green mixed with vinegar. Item, make a ground of the same green, and when it shall have become dry, cover it with size ('caule').
"If you wish to write in gold, take powder of gold and moisten it with size, made from the very same parchment on which you have to write; and with the gold and size near to the fire; and, when the writing shall be dry, burnish with a very smooth stone, or with the tooth of a wild boar. Item, if then you should wish to make a robe or a picture, you may apply gold to the parchment, as I have above directed, and shade with ink or with indigo, and heighten with orpiment."