Commissioned by the Central Provident Fund Board in the 1970s, it once decorated the walls of the former CPF Building at 79 Robinson Road, and decades of public display had taken its toll. The National Gallery Singapore (NGS) purchased the work for its collection in 2015.

It was only after a lengthy three months of planning on paper that the Japanese “art doctor” – who usually handles smaller items like books and letters – was confident to start the conservation process of the largest paper object she had ever laid hands on.

Chen (1906-1991) started painting gibbons from possibly as early as the 1930s, and the lively primates are his most recognisable subject.

Painter Chen Wen Hsi (1985-1988) in a portrait photograph (silver gelatin print) taken by Singaporean photographer and Cultural Medallion recipient Chua Soo Bin. PHOTO: COURTESY OF NATIONAL GALLERY SINGAPORE

Before settling in Singapore in 1949, the Guangdong-born artist had never seen a real gibbon.

But at his home here at 5 Kingsmead Road, he kept a menagerie that included, at its peak, six pet gibbons that he painted by observation.

Chen’s lifelong quest to capture the gibbon’s form culminated in this panoramic scene with 14 mischievous apes.

An image of Chen Wen Hsi’s Gibbons pre-conservation. The painting is a collection of National Gallery Singapore and conservation of this artwork was funded by the Bank of America Art Conservation Project. PHOTO: COURTESY OF NATIONAL HERITAGE BOARD, SINGAPORE

An authentic painting of his can fetch upwards of $600,000 at auction, but many Singaporeans own a mint copy of his work for much less: Two of his gibbons swing playfully on the back of the Republic’s $50 banknote.

The conserved Gibbons will be a centrepiece in a new permanent Singapore art history exhibition at the NGS, which is set to open the first gallery in December.

The exhibition will fully open its three galleries in July 2025, ahead of the Republic’s 60th birthday.

The pressure was on for Ms Mariko’s team at the Heritage Conservation Centre (HCC), a high-security, purpose-built facility tucked away in Jurong Port Road. It is where more than 250,000 artefacts and artworks in the National Collection are carefully maintained and stored.

Scroll mounter Eve Zhang perches on a ladder placed on two platforms with wheels on both ends to provide elevation, allowing the team to better access the middle of the painting.

But like any good surgeon, Ms Mariko – who is senior paper conservator at HCC – prefers to focus on the material facts of the patient in the room than its outsized importance in the world: “Once I decide to do any treatment, I don’t really think about the significance of the artwork – whether it’s very important or if it’s my mother’s dictionary.”

A loss seen at the edge of the painting. Tears and losses can be due to various reasons.
For Gibbons, many of the losses were due to brittle paper, wrong handling and poor quality framing materials in the past.

The conservation of this ink work began, surprisingly, with a hot bath of sorts.

Ms Mariko and her team climbed atop a moveable bridge and poured buckets of deionised water – close to 100 deg C – onto the paper’s surface, in a bid to remove water-soluble impurities which cause stains.

The gibbons became submerged in a shallow “pond”, until the art conservators pressed and rolled a towel on the artwork’s surface a few moments later to absorb the moisture.

The washing process was repeated three to four times, and the drying process took more than three months.

“It’s not like washing clothes in the laundry,” Ms Mariko quipped. The process had to be slow, as paper is more susceptible to damage when wet. But once dried, the paper is less brittle.

Although one would expect the water treatment to cause the Chinese ink and colour to run, the fibre in the high-quality rice paper absorbs the ink so firmly that the painting remains intact even if exposed to water.

Scroll mounter Eve Zhang mixing colours using Chinese pigments. The process of adding colours to an area of a painting that has lost its original colours is known as retouching or “inpainting” in the conservation field.
The aim of inpainting “is not to completely disguise the previous colour loss, but to make the loss blend into the surrounding areas better”, said paper conservator Mariko Watanabe-Hirano.

Conservation on such a scale can be athletic work.

Scroll mounter Eve Zhang working on Gibbons, the 1977 ink masterpiece by pioneer Singapore artist Chen Wen Hsi. Conservation work on the 190cm by 488cm artwork by a team of nine conservators spanned over a year.

“It’s like holding a yoga position. After one day, when we go back, our whole body is sore,” said scroll mounter Eve Zhang, 50, as she put on the final touches before the painting was rolled up.

Ms Zhang removing excess moisture from the painting. Signs of foxing are still evident, although the conservators say the yellowing is much less apparent than before the conservation process started.
Ms Zhang removing a very small lump of paper using a small knife from the lining paper that the conservators have applied on the back of the artwork. Such unevenness can happen while they brush over the lining paper for better adhesion.

Holding a slab of insect wax no bigger than a computer mouse, she took four minutes and 35 seconds to slather the entire back of the painting in wax – which keeps the paper flexible – stopping just once to catch her breath midway.

Ms Zhang applying wax to the back of the painting, where lining paper has been added as backing and to hold the tears and holes together.

Ms Zhang, who was born in Hangzhou and is now a Singapore citizen, apprenticed under her art conservator father and runs her own restoration studio, Wen Bao Zhai. She is regularly engaged by HCC for the conservation of Chinese ink works.

Ms Zhang burnishing the back of the art piece with a stone after wax has been applied. This process can make the paper more supple and flexible, which aids in rolling and unrolling the art piece.
Ms Zhang flicking the Gibbons paper canvas so that it moves in waves, before the artwork is flipped over. If the waxing and burnishing are done evenly, the paper flows evenly from edge to edge.
Ms Zhang trimming off excess areas of the silk border attached to the edges of the artwork’s paper. Chinese paintings are traditionally mounted with silk borders.

Ms Mariko’s team of nine is part of the close to 30 conservators working behind the scenes to bring more than 400 works on show at the yet-unnamed exhibition.

The team protecting the conserved piece with acid-free paper before it is rolled up for storage. Acid-free tissue was inserted to minimise the abrasion and risk of the painting's surface sticking to the other surface, in case temperature and room humidity increase.
It’s all hands on deck while rolling up the masterpiece, Gibbons, for storage. Said Ms Mariko (fourth from left): “It is critically important for it to be rolled up as straight and taut as possible to minimise any uneven pressure, and to achieve this, we did it a few times.”

Other works include Tchang Ju Chi’s Indian Boy (1939), which had lost much of its colour. The oil painting depicts what is likely a South Indian Hindu boy in a lungi, or sarong wrap.

Stroke by stroke, Italian conservator Vanessa Ubaldi, 34, painstakingly worked to restore the work to its colourful glory.

Painting conservator Vanessa Ubaldi using a handmade “appoggia mano”, or hand rest, for more stability and precise strokes as she works to restore Tchang Ju Chi’s Indian Boy – which had lost much of its colour – to its former glory.

Using conservation-grade watercolour for the touch-ups ensures that the conservation material can be distinguished and, if need be, reversed.

Ms Ubaldi showing a section of the painting that has been retouched. The “chromatic selection” technique, which applies primary or secondary colours in small brush strokes without mixing, is done using water colours and varnish colours made for conservation. The method allows the restored areas to remain distinguishable upon close inspection.

NGS curator Teo Hui Min, 34, said the painting is an “exceedingly rare” piece as the gallery has only 14 of Tchang’s works, in varying conditions.

Tchang, born in 1904 in Guangdong, was one of Singapore’s earliest practising artists but was killed in 1942 during the Sook Ching massacre during the Japanese Occupation.

He will be the inaugural subject of a mini project space for Singapore artists at the new exhibition space come 2025.

MINIMAL INTERVENTION

While conservation principles dictate that intervention should be minimal and reversible, it is balanced with the expectation that the work should look its best.

ST PHOTO: NG SOR LUAN

A final detail reveals why Gibbons is a masterpiece worthy of almost a year of conservation, a journey supported by a donation by the Bank of America for an undisclosed sum of between $50,000 and $299,999.

Gibbons is executed on a single sheet of rice paper that was likely custom-made. It is a feat that has baffled Ms Mariko, who said that a single sheet of such size is difficult to make.

Ms Mariko (left) and Ms Zhang flipping the painting over. Flipping and rolling are delicate processes that require experience and attention.

The fact also impressed curators – particularly given the unforgiving nature of the Chinese ink medium.

“Every brush stroke you place on the paper – that’s it,” Ms Teo explained.

“It’s not like other mediums, such as oil on canvas, where there is a certain degree of correction that can take place.”

Ms Zhang retouching the colours lost from the original artwork.

Chen would presumably have reached a certain level of mastery and confidence in his composition and execution to attempt a painting of Gibbons’ scale, she said.

The CPF Building was not the best place to appreciate the grandeur of the work, said Dr Adele Tan, lead curator of the exhibition, as there were limited viewing points.

National Gallery Singapore curator Teo Hui Min (left) discussing Chen Wen Hsi’s oil on board work Oasis (1972) during a media tour on Sept 5. The painting was previously conserved, so it only needed a light dusting and protection on the verso in preparation for exhibition.

Come December, the work will not only look its best, but it will also be positioned to give museum-goers a more generous vantage point – as Chen would have probably hoped.

Images of Chen Wen Hsi’s Gibbons before and after treatment. Gibbons will be the centrepiece in a new permanent Singapore art history exhibition at the National Gallery Singapore. PHOTOS: COURTESY OF NATIONAL HERITAGE BOARD, SINGAPORE

“It’s a bit of a homecoming for the painting,” Dr Tan added. “To a place where you can look at it properly.”