§ X. OF THE DECORATION OF LEAD.
One of the most usual methods of decorating lead was to gild it; whole domes were gilt in this way. The dome of St. Sophia at Constantinople seems to have been so treated, and the great arc of gold dominating such an Eastern city must have been a most impressive sight. Many of the late domes are partly gilt, as at the Invalides in Paris. The roof of the ancient basilica at Tours is said to have been like “a mountain of gold.”
Old recipe books of the last century give instructions for gilding lead. The following are examples:—
“Take two pounds of yellow ochre, half a pound of red lead, and one ounce of varnish, with which grind your ochre, but the red lead grind with oil; temper them both together; lay your ground with this upon the lead, and when it is almost dry, lay your gold; let it be thoroughly dry before you polish it.”
For another ground—“Take varnish of linseed oil, red lead, white lead and turpentine; boil in a pipkin and grind together on a stone.”
“Or take sheets of tinfoil, and grind them in common gold size; with this wipe your pewter or lead over; lay on your leaf gold and press it with cotton; it is a fine gilding, and has a beautiful lustre.”
Dutch metal was also used on a ground of varnish and red lead, as in second recipe; or gilt leaves of tinfoil on white lead ground in linseed oil, this last took a polish “as if it had been gilded in fire.” Dutch metal should be lacquered on the surface. A cheap substitute for gilding could doubtless be made for large surfaces by laying tinfoil lacquered gold colour. Or for statues the surface of the lead might be made bright and lacquered.
The external gilding on the Ste. Chapelle in Paris was done in leaf gold on two coats of varnish.
Smaller decorative objects of lead in the middle ages were often entirely gilt or parcel gilt in patterns; for instance, in an inventory of 1553 we find an altar cross “of lead florysshed withe golde foyle.” The effect of silver is obtained by “tinning” with solder, and when this is intended to form patterns on the surface of the lead the method is thus described by Burges. The surface is coated with lamp black mixed with size; the pattern is either transferred on it or drawn direct and then marked round with a point; all the part to be tinned has the surface removed by a “shave hook” so as to leave the pattern quite bright, a little sweet oil is rubbed over this and the solder is applied and spread in the usual way of soldering with a “copper bit.” This is more conveniently done in the shop, but the spire at Chalons was decorated in this way long after the lead covering was finished. A specimen of this work prepared by Burges may be seen in the Architectural Museum, Westminster.