Painting technique

The department painting-conservation of the Museum fur Hamburgische
Geschichte is in search of a special painting technique which we
describe below. If you have ever seen a similar technique used in
the 18th century or before we like you to contact: Silke
Beiner-Buth, Painting Conservator, <info [at] HamburgMuseum__de>.

For exhibition purposes we recently have conserved/restored two
portraits of Johann Ernst Heinsius, a portrait painter from
Weimar/Germany who worked from 1780-1784 in Hamburg. Working with
these portraits and examining 3 further portraits of Heinsius, we
discovered an extraordinary painting technique, which we have never
seen before on comparable paintings:

Heinsius used to spread very rough lead white pieces (thickness 1-2
mm) on top of his red ground-layer (priming coat) before he started
to use his oil-colors. The lead white can't be seen as a white
color, but only as a rough surface. We guess he wanted to get by
this a special kind of light reflection with the optical effect of a
smooth transition from one color to the next, the colors should
merge into each other.

Our aim is to come to know what gives Heinsius the idea for this
technique and if he follows someone's example. To solve this problem
we looked to the literature of painting techniques and found a hint
concerning baroque painters--especially Caravaggio was mentioned as
a painter who used sandy, rough and unpolished ground-layers
(Rotondi, Pasquale /Urbani, Giovanni: Il restauro delle tele del
Caravaggio in San Luigi dei Francesi a Roma. in: Boll. ICR 1966, p.
11-20) but--we are disappointed--couldn't find information about a
painter who used lead white.

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                  Conservation DistList Instance 12:88
                   Distributed: Tuesday, May 18, 1999
                       Message Id: cdl-12-88-021
                                  ***