Thus also, if you take Putty, and melt it with any transparent colour’d Glass, it will make it become an opacous colour’d lump, and to yield a paler and whiter colour than the lump by reflection.
The same thing may be done by a preparation of Antimony, as has been shewn by the Learned Physician, Dr. C.M. in his Excellent Observations and Notes on Nery’s Art of Glass; and by this means all transparent colours become opacous, or ammels. And though by being ground they lose very much of their colour, growing much whiter by reason of the multitude of single reflections from their outward surface, as I shew’d afore, yet the fire that in the nealing or melting re-unites them, and so renews those spurious reflections, removes also those whitenings of the colour that proceed from them.
As for the other colours which Painters use, which are transparent, and us’d to varnish over all other paintings, ’tis well enough known that the laying on of them thinner or thicker, does very much dilute or deepen their colour.
Painters Colours therefore consisting most of them of solid particles, so small that they cannot be either re-united into thicker particles by any Art yet known, and consequently cannot be deepned; or divided into particles so small as the flaw’d particles that exhibit that colour, much less into smaller, and consequently cannot be diluted; It is necessary that they which are to imitate all kinds of colours, should have as many degrees of each colour as can be procur’d.
And to this purpose, both Limners and Painters have a very great variety both of Yellows and Blues, besides several other colour’d bodies that exhibit very compounded colours, such as Greens and Purples; and others that are compounded of several degrees of Yellow, or several degrees of Blue, sometimes unmixt, and sometimes compounded with several other colour’d bodies.
The Yellows, from the palest to the deepest Red or Scarlet, which has no intermixture of Blue, are pale and deep Masticut, Orpament, English Oker, brown Oker, Red-Lead, and Vermilion, burnt English Oker, and burnt brown Oker, which last have a mixture of dark or dirty parts with them, &c.
Their Blues are several kinds of Smalts, and Verditures, and Bise, and Ultramarine, and Indico, which last has many dirty or dark parts intermixt with it.
Their compounded colour’d bodies, as Pink, and Verdigrese, which are Greens, the one a Popingay, the other a Sea-green; then Lac, which is a very lovely Purple.
To which may be added their Black and White, which they also usually call Colours, of each of which they have several kinds, such as Bone Black, made of Ivory burnt in a close Vessel, and Blue Black, made of the small coal of Willow, or some other Wood; and Cullens earth, which is a kind of brown Black, &c. Their usual Whites are either artificial or natural White Lead, the last of which is the best they yet have, and with the mixing and tempering these colours together, are they able to make an imitation of any colour whatsoever: Their Reds or deep Yellows, they can dilute by mixing pale Yellows with them, and deepen their pale by mixing deeper with them; for it is not with Opacous colours as it is with transparent, where by adding more Yellow to yellow, it is deepned, but in opacous diluted. They can whiten any colour by mixing White with it, and darken any colour by mixing Black, or some dark and dirty colour. And in a word, most of the colours, or colour’d bodies they use in Limning and Painting, are such, as though mixt with any other of their colours, they preserve their own hue, and by being in such very smal parts dispers’d through the other colour’d bodies, they both, or altogether represent to the eye a compositum of all; the eye being unable, by reason of their smalness, to distinguish the peculiarly colour’d particles, but receives them as one intire compositum: whereas in many of these, the Microscope very easily distinguishes each of the compounding colours distinct, and exhibiting its own colour.
Thus have I by gently mixing Vermilion and Bise dry, produc’d a very fine Purple, or mixt colour, but looking on it with the Microscope, I could easily distinguish both the Red and the Blue particles, which did not at all produce the Phantasm of Purple.