Wood Conservation Final

Historical Evolution

• wooden panel paintings are mentioned and found in Egypt

• Continued during the Ancient Greek, Roman period with similar execution technique, constant in Europe til 13th century CE

• Wood species used was mostly local material, easily sourced

• Usually they glued several layers of different wood donors together, crossing the grain perpendicularly

• Very few examples of Greek and Roman panel paintings survived

2 Techniques

encuastic- wax, hot or cold

animal glue tempera- mixed technique

• wax higher quality- more bold colors, more contrast

• Tempera- duller, chalkier colors with finer gradations

• Boards- majority imported woods (lime, oak, cypress, cedar…)

• Layer of plaster→ paint→ gold leaf

wooden panel painting evolution 3 phases

• Byzantine period 6th-13th century

• Transition period 13th-14th century

• Renaissance period 14th-16th century

Byzantine Period Art

The artistic expression was limited, based on precisely defined rules for the representation and execution technique

• earliest icons 5-6th century

• Few examples left due to Barbarian invasions and the start of new techniques

• General characteristics already similar to wooden panel painting of 14th century

• Tempera was used, applying binders like glues, egg, lattice of figs, casein

Sequence of Painting Technique 6-13th century

1. Tracing the drawing with charcoal and ochre, then scoring the areas to separate those to be painted or gilded

2. Apply bole, and gold leaf with different adhesives

3. Application of color to figures in a uniform way with a medium tonality

4. Darker areas and shadows

5. Lightest tonality til the highlights

Transition Period 13-14th century

• new artistic expression evolved

• More realistic representation of figures

  • More volume

  • Space between figures

  • More architecture

• Golden ground was no longer necessary, depended on the wish of the artist or commissioner

• Similar materials to previous period, with future changes of the use and mixing of colors

Sequence of Painting 13-14th century

1. A drawing on cardboard with all the details and the chiaroscuro shading, was transferred by spolvero on the gesso which was still slightly soft

2. Application of bole and gilding where necessary

3. “Verdaccio” green color for the flesh preparation

4. Dark, medium, and light tonality applied following the form of the figure or drapery

5. Light glazes would sometimes be applied to the face

Renassaince Period 14-15th century

• transition from tempera to oil

• Oil was more fluid and more freedom to the artist, more transparent and glossy

• Panel paintings are simplified: thinner support and preparatory layers

• Different types of tempera: thin tempera (only with egg), fat tempera (with egg, resins, oil)

• In Tuscany egg tempera lasts longer, while Venice starts to use oils very early

Last Period 16-17th century

• wooden panel technique is in decline

• 1600-1700s the wooden panel paintings are gradually substituted completely by canvas paintings

  • Canvas does not crack or veneer(thin decorative/top layer) whereas wood moves

  • Canvas may be any size

  • Canvas can travel easily

Wooden panel painting layers

• wood panel, canvas, glue

• Thick gesso

• Fine gesso

• Spolvero (drawing transfer), scoring, apply bole

• Gilding

• Painting

14th century frame models

• frames became attached to architectural schemes

• The arch and pointed arch were supported by twisted columns

  • Often decorated with sacred representations inspired by paintings

• Marked the birth of triptych and polyptych

  • Imitating the facades of gothic churches

Renaissance frames

• Tabernacle- Painting and frame created separately then assembled together

• Artists were commissioned to create a wide variety of paintings or subjects not just religious

  • Tondo- plant based decorative frames inspired by teracottas

    • Mainly used for compositions of Madonna and child

  • Cassette- columns disappeared, bases were reduced

Dark inlay

Carving a cavity into solid wood, to hold a wooden cutout of the same shape and size

Toppo-inlay

generally used for frames, repeatable geometric motifs, created by assembling strips of wood joined together to create distinctive geometric designs at the top

Shellac

natural resin secreted by the female lac bug

• durable

• Non-toxic

• Eco-friendly

• Creates deep rich finishes, compatible with all woods

Shellac: production process

variations are created by the type of tree, are, and beetle

How to prepare shellac

1. Measure and mix ingredients

2. Wait 15 min, mix again, wait 15 min

3. If all flakes melted, put in airtight container

4. Leave it to sit for 24 hours

Makes small amounts

Shelf life under a year

Negative aspects of shellac

• dissolves in and by alcohol

• Perfumes can damage surface

• Water rings can form

• Scratches can be quite visible

• Sensitive to heat

positives to shellac

• different tonalities to choose from

• Good adherence

• Easy to remove

• Non toxic

• Sufficiently hard, can be sanded

Balsite

• missing wood is reconstructed with new or seasoned wood

• Fillers- paste used to fill in spaces and binder to adhere to original

  • Hardens and minimal shrinkage

  • Easy to use

  • Resistant to biological attack

  • Easy to color

  • Dry in 24 hr

  • Surface can be treated like wood

• Araldite/ vynavil + wood paste = balsite

Ethical principles

• reversibility- the ability to remove/replace or modify interventions in the future without damaging the original material

• Distinguishability- intervention must be seen by the naked eye compared to the original

• Compatibility- use of chemical or physical materials similar to original

• Minimal intervention- limiting oneself to what is strictly necessary

“First, do no harm”

• first do not create further damage

• Lack of professional qualification

• Team of three persons

  • Art historian

  • Scientist

  • Restorer