This section is from the book "The Professed Cook: Or, The Modern Art Of Cookery, Pastry, And Confectionary", by B. Clermont. Also available from Amazon: The professed cook.
For Red, take Beet-root baked and pounded, put a little Cullis to it, and sift it in a Stamine, taking care that it be pretty thick: You may make a little thin Paste of it, which cut to what form or slower you please, to be applied upon any thing you have a mind to flourish; basting the Meat first with Whites of Eggs to make the Colour stick, and then putting it into the oven a moment, just to dry it.
Yellow is made with Yolks of hard Eggs pounded, and a little Cullis, and fisted as the former.
Cochineal and Saffron also make very good Colours; and if you mix a little melted Ifinglass with each, it Will make the Jelly stronger, and fitter to cut into different shapes, with which you may garnish any cold Dishes, according to fancy.