APPROACHING VIETNAMESE LACQUER FROM A COATING STUDIOLOGY PERSPECTIVE (Part 1)

(To this day, many experts and artists specializing in lacquerware in Vietnam still proudly believe that Vietnamese lacquerware belongs to the Vietnamese people, and only Vietnamese people fully understand and have the authority to speak about it. How unfortunate! This "empiricist culture," when combined with an "authoritarian culture," hinders people in every way – sometimes even blinding and narrow-minded… The disaster that befell Nguyen Gia Tri's "Spring Garden" at the Ho Chi Minh City Museum of Fine Arts can be seen as an example.

Following the suggestion of a "disciple" studying in a "dying" country, approaching Vietnamese lacquerware through the field of COATING STUDIES using reputable English, French, and German data sources, I stumbled upon countless valuable lessons…)

Part 1: THE BOTANICAL AND GEOCHEMICAL NATURE - THE ENDOGENOUS CORE OF VIETNAMESE LACQUER

The argument about the origins of Vietnamese lacquer begins with identifying the biological nature of the main raw material: lacquer resin. Studies that formed the basis of 20th-century French-language documentation, from the ethnographic records of Henri Oger to the field surveys of scholars from the French School of Far Eastern Studies (EFEO), focused on uncovering the species differences between the vegetation of Indochina and the Chinese plains. The native Vietnamese lacquer tree is the species Toxicodendron succedaneum (from the hills of Phu Tho), which is completely genetically and distinctly different from the species Toxicodendron vernicifluum endemic to China and Japan.

This botanical difference leads to profound consequences regarding the geochemical structure of the two types of lacquer coatings. Molecular analysis using pyrolysis gas-gas mass spectrometry (Py-GC-MS) by modern heritage laboratories at the Guimet National Museum of Asian Art (Paris) and the French Museum Research and Restoration Center (C2RMF) has demonstrated that the core of Chinese and Japanese lacquer is dominated by short-chain alkyl-catechol compounds containing 15 carbon molecules (Urushiol), while Vietnamese lacquer resin is composed of long-chain alkyl-catechol compounds containing 17 carbon molecules (Laccol).

The longer hydrocarbon chain in the Laccol molecule creates a larger distance between the linked links when the lacquer resin undergoes polymerization. This highly spaced molecular network determines the characteristic physical properties of Vietnamese lacquer: the cured lacquer film always maintains high mechanical toughness, high intrinsic elasticity, and slow hydrolysis in humid tropical environments. In contrast, the short C15 chain of Urushiol compresses the molecules tightly, creating a surface with a dense, glass-like network structure, achieving absolute hardness and high scratch resistance, but also brittleness and difficulty in abrasion.

The second difference lies in the natural water content of the raw resin. Phu Tho lacquer resin contains a natural water content of up to 25% - 30%, much higher than the 10% - 20% of Chinese raw lacquer. The drying process of the lacquer does not occur by the usual solvent evaporation but depends on organic polymerization under the catalysis of the enzyme Laccase, a reaction that requires the environmental humidity to be maintained at 75% to 80%. The high intrinsic water content causes the lacquer to dry slowly, and the curing process occurs steadily from the core of the wood outwards to the surface. The slow-drying properties and the amber-like, flexible film of Laccol were the decisive mechanical prerequisites for Vietnamese craftsmen to perform mechanical intervention using water-grinding techniques without cracking the substrate structure.

ARCHAEOLOGICAL PROCESS AND HISTORICAL SOURCES

The argument of the female artist and researcher Alix Aymé, published in the journal Études Outre Mer (December 1952), represents the pinnacle of old colonial academic thinking. She asserted that Annamese art was entirely a reflection of Chinese art after nine centuries of domination, and cited the legend of the scholar Tran Tuong Cong (Tran Lu) in the 15th century to affirm that lacquer technology was only introduced to Vietnam from this point onwards. Throughout the latter half of the 20th century, field archaeological discoveries in Vietnam provided scientific evidence that refuted this argument.

Archaeological excavations at the Viet Khe boat burial site (Hai Phong), dating from the 5th to 4th centuries BC—almost five centuries before Ma Vien's expedition—uncovered wooden artifacts such as axe handles, oars, and, notably, entire boat-shaped coffin structures coated with a thick layer of pure lacquer resin. Following this, the system of hollowed-out tree trunk tombs at Duong Du, Chau Can, and Kiet Thuong, belonging to the late Dong Son culture period, also demonstrated a sophisticated technique of using lacquer resin to protect burial artifacts from termites and water damage.

This evidence establishes a reality: the lacquer art of the ancient Vietnamese originated from a deeply ingrained "protective technique" adapted to the hot and humid climate of the riverine region, entirely independent of the feudal industrial centers of the North.

Re-evaluating the historical role of Tran Tuong Cong (Tran Lu) in Binh Vong village (Thuong Tin) also needs to be based on the development patterns of folk craft guilds. Before the 15th century, the spiritual architecture of the Ly-Tran dynasties, with its lacquer and gold leaf techniques at Thuy Pagoda, Dien Huu Pagoda, and ancient statues, demonstrated the widespread nature of lacquerware. Tran Lu's act of going on a diplomatic mission to the Ming dynasty and bringing techniques from Dali Prefecture (Yunnan) back to Vietnam was not the beginning of a new profession, but rather a high-level technology transfer. He brought back new paint formulas, methods for dyeing lacquer resins, and the organizational structure of professional guilds. Alix Aymé made a mistake in equating the act of technological improvement and expanding the guild's scale with the invention of a native craft.

THE TRANSFORMATION FROM HANDICRAFT TO SCHOLAR PAINTING

The great turning point that transformed the rustic lacquer material into a flat painting language (Laque poncée) occurred in the 1930s at the Indochina College of Fine Arts, marking a marriage of thought between Vietnamese folk art and the Western academic compositional system. Before this period, lacquer art was confined to two states: either as a spiritual decorative covering (lacquer with gold leaf) serving royalty and deity, or as a folk art object that merely copied ancient motifs. The arrival of the painter Joseph Inguimberty and the headmaster Victor Tardieu triggered an unprecedented experimentation with materials in the history of East Asian art.

This transformation completely reversed the creative philosophy of neighboring lacquer art centers. While the Chinese opted for the "coating" philosophy using the technique of applying hundreds of layers of extremely hard Urushi lacquer to create raised carvings, and the Japanese chose the technique of "surface decoration" (Maki-e, sprinkling gold and silver powder onto a wet lacquer layer), Vietnamese artists (Nguyen Gia Tri, Pham Hau, Tran Van Can) invented the technique of "polishing" (ponçage).

Due to the resilient C17 chain structure of Laccol, the artist can layer many different colors of lacquer, interspersed with the application of gold leaf, silver leaf, eggshells, and mineral powders deeply embedded in the lacquer layers. Then, charcoal and water are used to smooth the surface. This water-based polishing process is a controlled destruction, abrading the top layers of lacquer to reveal the hidden color effects beneath.

The optical effect of Vietnamese lacquer paintings depends directly on the amber-like transparency of the aged lacquer. When external light shines on the painting, it doesn't reflect off the surface like the mirror-like sheen of Japanese Urushi lacquer, but instead passes through the hazy, reddish-brown layers of lacquer, reaching the gold and silver leaf at the bottom of the painting before reflecting back to the viewer's eye. This multi-layered light refraction phenomenon creates the "inner light" effect, or the profound depth of the flat lacquer painting structure, transforming the material, originally used to enclose and protect objects, into a language expressing the artist's inner world.

CHEMICAL DAMAGE MECHANISM OF MULTI-LAYERED STRUCTURE UNDER EXTERNAL INFLUENCE

A complete Vietnamese lacquer painting is a complex physical system comprising: a wooden core, a binding layer (a cloth mixed with alluvial soil and raw lacquer), layers of organic pigments, layers of precious metals (gold leaf, silver leaf), fragments of natural materials (eggshells, seashells), and an outer protective coating. The chemical sensitivity of the Laccol molecule makes this multi-layered system highly susceptible to serious damage when exposed to incorrect chemicals and solvents during storage or restoration.

The 2019 damage to the national treasure "Spring Garden of Central, Southern and Northern Vietnam" is a prime example of the destructive impact of non-neutral pH substances on the structure of classical lacquerware. The use of strong alkaline industrial soap combined with stone powder and rough mechanical methods stripped away the outermost protective layer of the eggshell. Once the outermost organic polymer layer was destroyed, the "mache" structure (the extremely thin layer of color cushioning between the gaps in the eggshell) dissolved and washed away, causing the eggshell fragments to lose their warm, hazy hue and become pale and dry.

For precious metal layers such as gold leaf (usually a gold alloy containing copper and silver) and silver leaf embedded beneath the lacquer, the penetration of strongly polar organic solvents (acetone, methanol) or sulfate-containing compounds will trigger deep chemical corrosion reactions. Silver leaf reacts with sulfur derivatives to form silver sulfide, changing the color from a shimmering silvery white to a deep grayish-black, completely eliminating the light-reflecting ability of the base layer of the painting.

At the same time, aromatic hydrocarbon solvents (xylene, toluene) can dissolve the lacquer layer (the rough lacquer layer that acts as a binder to fix the gold/silver leaf), causing metal drift and shattering the thin gold leaf crystal lattice into microscopic particles under the shrinkage effect of the wooden core.

CHALLENGES AND SCIENTIFIC DIRECTIONS FOR THE CONSERVATION OF LACQUER HERITAGE IN VIETNAM

The current state of conservation and restoration of lacquer paintings in Vietnam faces a significant gap between intuitive practice and modern museum science. The majority of large-scale restoration projects in the country still rely on the individual skills and artistic intuition of master painters. While this method has advantages in understanding the manual water-polishing technique, it reveals serious limitations in terms of physico-chemical accuracy, easily leading to a tendency to "renew the artwork" rather than "preserve its original state."

The shortage of authentic Phu Tho lacquer raw materials and the tendency to overuse industrial paints (polyurethane), pigments, and Japanese paints to touch up peeling areas is a real threat. Industrial paints dry by solvent evaporation, creating a hard, inert film that lacks the light-transmitting properties of Laccol. Mixing these chemically dissimilar materials on the same surface of an antique painting will alter the optical structure of the artwork and cause uneven shrinkage forces, directly leading to cracking at the interfaces between the old and new paint layers.

The pilot program for transferring conservation training curricula in cooperation with Germany and Japan in Vietnam is currently focusing on addressing this systemic bottleneck by developing a set of interdisciplinary technical standards:

* Standardizing the diagnostic phase: Mandatory application of non-destructive testing methods (FTIR, UV spectroscopy) to create digital medical records for artworks before restoration, in order to clearly determine the age and nature of the solvent layers used by the artist.

* Standardizing the cleaning and bonding process: Replacing harsh detergents with biological cleaning solutions with a pH of 7 or natural enzymes, adhering to the principles of "Minimal Intervention" and "Reversible".

* Mastering the curing chamber technique: Applying electronic control technology to the temperature and humidity parameters of the lacquer curing chamber according to Japanese standards helps to stably and uniformly fix the dried Laccol restoration film from the inside out, matching the mechanical properties of the ancient lacquer painting base.

This integration protects the authenticity of Vietnamese lacquer art under a strict scientific barrier, abandoning spontaneous, handcrafted thinking to enter the trajectory of systematic international heritage preservation.

NGUYEN HUNG

(Excerpt from the "Compilation of Documents" folder - abridged)

Gửi ý kiến phản hồi

Gửi ý kiến phản hồi