Badania odkształceń obrazów pod wpływem zmian wilgotności względnej powietrza

• Authors: Matejak Mieczysław , Skwarek Adam

Title variants

EN

STUDIES ON THE DISTORTIONS OF PAINTINGS UNDER THE EFFECT OF CHANGES IN RELATIVE HUMIDITY OF THE AIR

• Languages of publication: PL EN

Abstracts

EN

The aim of this work was to examine distortions of paintings during their dampening and drying. Examinations were made on copies of paintings with oil and distemper polychromy. On both sides of under-paintings made of spruce wood four tensometers were sticked, in two opposite pairs. Identical chalk and glue mortars, covered with polychromy, were then prepared. The coatings were varnished. Endings of the tensometers sticked to wood were then taken out above the surface of polychromy. After near 6 months tensometers were glued onto polychromies over those put direct on the board. Thus, we got paintings with tensometers on polychromy, under the mortar and an unpolychromed surface of the underpainting. Distortions of paintings, conditioned out in the air with relative humidity of 35% at temp. 20°C., after their transfer to the air with relative humidity of 75% at the same temperature, are shown on illustrations 2 and 3. Illustration no 2 (distemper polychromy) reveals a rapid bulging of wooden layers of unpolychromed side of the painting caused by the adsorption of water vapour and diffusion of water into the painting. This brings about the pressing of wood layers, the humidity of which under polychromy is smaller than the humidity of outside layers. With the time water diffuses towards polychromy and it comes to levelling the humidity of the layers near polychromy. As can be seen from ill. 2 polychromy gets deformed proportionally to layers of the wood, on which it has been put. This proves its flexibility and fine binding with the base. The course of a curve of bulging measured by a tensometer placed on the board of the painting with oil polychromy is similar to that of distemper polychromy, while the layers under polychromy have shown a stronger and more permanent effect of pressing due to board deformation. This results from a flow of a smaller amount of water through oil polychromy when compared to distemper one. A curve of the deformation of polychromy had a different shape because of a poor cohesion with the groundwork and fragility. Curves of the deformation during the drying of paintings have an identical character to that during adsorption, which confirms results and their interpretation. The work done shows that the bulging of unpolychromed layers of the underpaintings is counteracted by under-polychromy layers that do not swell at that time. This brings about reducing dimensions of the layers that had become worst deformed and then, after a subsequent drying of the wood, to its initial humidity it leads to permanent shrinking and permanent buiging of the polychromy. The phenomenon of paintings’ distortion under the effect of dampening and drying of the underpainting can be prevented by putting on the opposite plane of polychromy the material with exactly the same permeability of water vapour as polychromy, which results in the same speed of humidifying the two surfaces of the painting. In the case( when the painting has got already distored, putting the material that would hinder diffusion of water vapour on the board will not change a shape of the under-painting.

• Publisher: Narodowy Instytut Dziedzictwa
• Journal: Ochrona Zabytków
• Year: 1985
• Issue: 3-4
• Pages: 308-311

Dates

published

1985

Contributors

author

Matejak Mieczysław

• dr inż., Wydział Technologii Drewna SGGW-AR w Warszawie

author

Skwarek Adam

• mgr inż., Wydział Technologii Drewna SGGW-AR w Warszawie

References

• Lucanus , Anleitung zur Restauration alter Olegemalde, 1828.
• E. P o p o w s k a, M. M a t e j a k, Wpływ klimatu na wilgotność drewna w zbiorach muzealnych, „Muzealnictwo” , nr 26/27, 1983, s. 128-133.
• P. J. Bois, Moisture Content in Homes, „Forest Products Journal” , 97, 1959, s. 427.
• J. Q. Jahn, Abhandlung uber das Bleichen... der ole, 1803.
• A. Szt yrak , Badanie wspołczynnika oporu dyfuzyjnego powłok malarskich, maszynopis, Wydział Technologii Drewna SGGW-AR, Warszawa 1975.

Identifiers

ISSN

0029-8247