Dictionarium polygraphicum. Sap green.

Dictionarium Polygraphicum:
Or, The Whole Body of Arts Regularly Digested.
Vol I.
London: Printed for C. Hitch and C. Davis in Pater-noster Row, and S. Austen in St. Paul's Church Yard. MDCCXXXV.
1735
SAP GREEN is a colour like that of an oak leaf, if it be us’d thin with common water, for this as well as the former wants no gum; but if it be us’d strong, will produce as dark a green as any.

It will be proper to try colours first on a white Dutch tile, and by thinning it with water, you may render it of what strength you please; and may brighten it very much, with adding to it a very little verdegrease.

There are two ways of making sap-green, viz. Take the flowers of the blue flag iris, or flower de luce, and press them while there is any juice to be got from them; boil this gently in a glaz'd pipkin till it grows thicks; adding a little alum to it, and it will make a very useful and lasting Green.

N. B. You must observe this, that in the boiling of any juice, &c. of the colours before-mentioned, you must always do it in an earthen pipkin; for if it be boil'd in vessels of metal, they will oftentimes change from the colours intended.

The second way to make a sap-green for the washing and illuminating prints, is to take the juice of buckthorn-berries; and tho' that juice simply will yield only dark purple of a very base hue; yet by adding tartar to it, it will change into a good sap green.

Either of these colours will mix with the liquid verdegrease above-mentioned, as well as make a delicate shade for it.

There is besides these, another Green which is admired by some persons, and that carries a good body with it, and with a degree of transparency too (as it may be made) but as it is commonly us'd, is a colour of a full body, and fit only for painting in miniature.

This is made by mixing Dutch pink with indigo to what de gree of colour they please; but the high preparation of French berries with indigo (see the Article YELLOWS) is much to be preferr'd to Dutch pink, especially as this answers all the intentions of Dutch pink, and carries a transparency with it, which the Dutch-pink has not.