The caves at Dunhuang are not falling down. They are being held up – by the Dunhuang Academy（敦煌研究院 Dūnhuáng yánjiūyuàn）, the institution responsible for the care and management of the site, working with the Getty Conservation Institute since 1989.[1]
The problem is salt, not age
The paintings are made on earthen plaster over soft rock. The serious damage is not fading but separation: the plaster lifting away from the bedrock behind it, and flakes of paint coming loose. Investigation showed the mechanism – humid summer air entering the caves raises the relative humidity enough to dissolve salts in the plaster, and halite is the main species responsible.[1][2]
Cave 85: one cave as a method
The two institutions chose Cave 85 – completed in 867, one of the larger caves, with some of the best Late Tang painting – as a model project. It ran from 1997 to 2010, and its aim was method as much as repair: understand the deterioration, test treatments on the site’s earthen plaster, stabilise detached plaster with an earth-based grout, fix flaking paint, then monitor the result. The techniques were designed to be usable at other caves at Mogao and at similar sites along the old routes.[1][2]
Which pressure is worse: weather or visitors
Both, and they interact. Because the salt problem is driven by humidity, the cave has to be closed during rain and high humidity; and because every person in a small painted chamber changes its air, the project also produced a sustainable visitor policy and a carrying capacity based on years of measurements. Photography – high-resolution, full documentation – was done partly so that the record survives even if the surface does not.[1]
The keepers before the scientists
Conservation at Mogao is older than the terms for it. The Library Cave – Cave 17 – was found in 1900 by Wang Yuanlu, the Daoist priest and caretaker of the site; its contents scattered across the world, and the question of who owns the past has been part of the caves’ history ever since.[2] What the modern keepers add is method: measured, published, repeatable.[1]
Why it matters beyond Dunhuang
Because the technique travels. The statement of cultural values, the monitoring plan and the preventive approach developed for one cave were explicitly intended for other Silk Road sites.[1][3] The keepers of the caves are, in the end, keepers of a method.
This piece accompanies the film Keepers of the Caves.
Read next: what is actually inside the caves, and how Buddhism reached this desert The film that goes with this piece is Keepers of the Caves.
Chinese words in this piece
- 敦煌研究院 Dūnhuáng yánjiūyuàn — the Dunhuang Academy
- 修復 xiūfù — restoration, conservation treatment
- 壁畫 bìhuà — wall painting
- 藏經洞 Zàngjīngdòng — the Library Cave, Cave 17, found in 1900
Questions
Who looks after the Mogao Caves?
The Dunhuang Academy, the institution responsible for the site, which has worked with the Getty Conservation Institute since 1989.
What is damaging the paintings?
Not only age. Humid summer air raises the humidity inside the caves and dissolves salts in the painted plaster – mainly halite – which causes the surface to flake and the plaster to detach from the rock.
Why was Cave 85 chosen?
It is a large Late Tang cave, completed in 867, with some of the best painting of its period. It was used as a model to develop conservation methods that could be applied at other caves.
The film, in words
Every caption card that appears on screen in the film, in order. The film has no narration – this is its full text, so it can be read and quoted.
Read the full text – 48 caption cards
- The cliff has stood above the desert for sixteen hundred years.
- People cut more than five hundred caves into its face.
- Painters, monks and merchants left their colours inside.
- Today the caves belong to the people who hold them together.
- Every morning a gate opens, and only so many visitors pass.
- Breath and warmth are the slow enemies of old paint.
- So the day is divided, and the doors close on time.
- Behind the gate, another kind of visitor works quietly.
- They have kept this place for more than eighty years.
- Upstairs, a laboratory measures what air and salt are doing.
- Small samples rest in sealed dishes, labelled and dated.
- A microscope turns pigment into a landscape of crystals.
- Azure comes from lapis, green from malachite, red from cinnabar.
- Knowing the recipe tells a conservator how to repair.
- Humidity is watched hour by hour, winter and summer.
- A crack in plaster is measured with a scale thinner than paper.
- Instruments sit ready on a tray, arranged like a surgeon's.
- Nothing here is fast, and nothing here is guessed.
- Then comes the hour when one person and one wall meet.
- A syringe slides behind the flaking paint, injecting grout.
- The plaster lifts, softens, and settles back against the rock.
- A fine brush touches colour into the missing line.
- The pigment is ground from stone, shell and earth.
- Matching a colour means testing it on a hidden corner first.
- One square centimetre can take an entire afternoon.
- Her hands are steady because her eyes have looked for years.
- A lamp is angled close, so no shadow falls on the work.
- Cotton swabs, tweezers, and a brush shaped like an eyelash.
- She works in silence, listening to the wall.
- Slowly the faded figure returns to the ceiling.
- A bodhisattva's sleeve, a dancer's ribbon, a merchant's horse.
- Repair is not making new. It is holding on.
- The best repair is the one you cannot see.
- Across the yard, another team photographs every square metre.
- Cameras move in measured steps along a rail.
- Each cave becomes thousands of overlapping images, stitched later by machine.
- Colours are corrected until the screen matches the wall.
- Then the caves travel, without the caves moving at all.
- Schoolchildren in other cities stand inside a painted grotto.
- A copy of a cave can be shown where the air is dry.
- Scholars compare paint from opposite ends of the road.
- The archive is the second cave, made of light.
- At dusk the last visitors leave and the sand cools.
- The conservators walk home along a wall that outlived empires.
- Tomorrow the gate will open again, and the work continues.
- Not because the caves are ours, but because they are not.
- We are only the ones standing here this century.
- Some things are kept by being handed on.
Twelve free pages on the objects of China – and ten Chinese words from the films – are in The Art of Chinese Tea: A First Look.
Sources
- [1] Wall Paintings Conservation at Mogao Grottoes – Getty Conservation Institute
- [2] The Conservation of Cave 85 at the Mogao Grottoes, Dunhuang – Getty Conservation Institute
- [3] Mogao Caves – UNESCO World Heritage Centre
The films and the music are AI-assisted and then chosen, written and cut by hand. Every claim above is drawn from the sources listed; anything we could not confirm has been left out.
Written and published by Eastern Whispers — how this site researches, and how it discloses its sources