think it a good idea to add a little table oil to the yeso mate, especially in
winter.... I’ve also seen good gilders add linseed oil to avoid the bubbles
the gesso tends to make. In my preparations I would never use either the
one or the other” (Véliz 1987:66). In the contracts it is not unknown to
find the number of layers of yeso grueso and yeso mate specified: “T he
painters must prepare all of the retable twice with fine gesso [guix groso]
and twice with gesso [guix primo] v ery well tempered so that the gold will
be very brilliant” (Sobré 1989:53, n. 17).
Advice also emerges from documents and treatises about the best
time of year for certain preparations; adaptations for hot, cold, or dry
weather also appear. In a contract from 1569 for the retablo mayorof
Astorga, the season of the year for preparing the panels is stipulated: “And
so that the said work is long lasting and permanent they must prepare [the
panels] in the season that is necessary and most appropriate, which is in
the eight months of winter, two before [the season of ] the Nativity and
two after, and the said preparation must be made with great care” García
Chico 1946:112).
Pacheco advises that the glue priming (gíscola) should be more
strongly tempered in winter and comments that in cold places such as
Castile, León and Burgos, and Valladolid and Granada, the glues are gener-
ally more strongly tempered. He adds that in wintertime the painters from
these places gild with red wine in place of water and that they also some-
times add linseed oil to the yeso mate (Véliz 1987:86–87).
Most references to applying the yeso grueso and yeso mate sug-
gest that the ground was applied in a liquid, brushable consistency and
subsequently scraped and smoothed when dry. Pacheco describes a
Castilian practice in which, after an application of three or four layers of
yeso grueso (with a brush), thickened yeso mate is spread on with a trowel
(Véliz 1987:86–87). Perhaps this use of thickened or gelled yeso mate has
contributed to the notable thickness of Castilian preparation layers.
The final smoothing of the preparations of yeso grueso and yeso
mate was accomplished with small, even-bladed knives (escaretas), which as
early as 1493 were recommended in preference to lija (usually interpreted
as sandpaper), although it is also possible that dry cuttlefish bone is meant
(Ramírez de Arellano 1915:39). Pacheco also recommends a blade rather
than lija for this purpose (Véliz 1987:88).
With increasing frequency, from the late fifteenth century through
the sixteenth century, a colored priming was applied over the white yeso
mate before or after the composition was drawn on the panel. A passage
from Pacheco suggests that this was applied prior to drawing: “With lead
white and Italian umber, make a color that is not too dark, and grind and
temper it... with linseed oil. This is the priming. With a large brush,
trimmed and soft, give the panel an even, all-over layer. After it is dry...
it is ready to be drawn and painted upon” (Véliz 1987:67–68). Elsewhere a
nearly transparent layer of gesso has been observed to “act as additional
priming and to ensure that the underdrawing would not show through in
the finished work” (Sobré 1989:55).References to drawing on panels are rare in the documents, although there
is one interesting contract that required that the master, Jaime Romeu of
Zaragoza, draw all the compositions on the narrative panels and the pre-
della, and the hands and faces of all the figures had to be painted by hisUnderdrawing
W P M A S C S 143