Painting Before and After Restoration: Reading a Cleaned Work

A painting before and after restoration is the same object photographed at two moments in its conservation history, and the two frames record two different operations. Cleaning removes material sitting on top of the artist's paint: airborne dirt, and the natural resin varnish that saturates colour when fresh and veils it in yellow-brown as it oxidises. Inpainting adds new paint where the original is gone. Neither should touch original paint, and keeping the two apart is what lets a collector judge whether a treatment rescued a work or rewrote it.

Key takeaways:

• Pictures over 100 years old carry a discoloured varnish unless a conservator treated them within the previous 50 years, according to Simon Gillespie, Director of Simon Gillespie Studio, in Art UK.
• ICOM-CC's terminology resolution of September 2008 defines restoration as action "based on respect for the original material" and counts varnish removal as both restoration and remedial conservation.
• Guideline 23 of the American Institute for Conservation, adopted August 1994, requires compensation for loss to be "documented in treatment records and reports" and "detectable by common examination methods".
• Acrylic paint entered wide artistic use in the 1960s according to Tate's glossary, and acrylic films stay sensitive to water and to solvents, narrowing the options on contemporary work.

What Cleaning and Varnish Removal Actually Change

Varnish exists to saturate paint. Simon Gillespie describes the effect as "rather like wetting a pebble: it brings out the colours and makes a two-dimensional depiction more life-like", and the film also screens the surface from dust. Organic resin varnishes oxidise, lose transparency and gloss, and shift towards yellow-brown. Collectors compounded this by having fresh varnish brushed over old, so one picture can carry several coatings. Most of what a viewer notices in a painting before and after restoration comes from this layer.

Cleaning means removing those non-original layers. Gillespie states the difficulty directly: "The challenge is to remove the varnish layers without damaging the paint layer beneath." Conservators test in inconspicuous areas a few millimetres across, working from the gentlest solvent upward. Ultraviolet examination comes first: a thick greenish-yellow fluorescence indicates natural resin, and darker patches mark earlier retouching.

Acrylic paint, which Tate's glossary dates to the 1950s and to wide artistic use from the 1960s, is frequently left unvarnished. The 2004 Tate Papers review by Elizabeth Jablonski and colleagues records that acrylic films remain "sensitive to swelling by water" after drying, and MoMA's painting conservators treat work "from traditional oil painting on canvas to experimental paint media used by contemporary artists". Without a sacrificial coating, grime embeds in the paint film itself.

Inpainting Versus the Artist's Hand

Inpainting is new paint applied by a conservator into an area where the original has been lost, and the American Institute for Conservation treats it as an intervention that must be documented, detectable and reversible. Guideline 23 of its Code of Ethics and Guidelines for Practice, adopted in August 1994, requires that compensation for loss be "documented in treatment records and reports", be "detectable by common examination methods", and not "falsely modify the known aesthetic, conceptual, and physical characteristics" of the object.

Three properties follow, and they are the three to look for in a report on a cleaned work. Inpainting stays inside the loss, without extending across sound original paint. It stays distinguishable under ultraviolet light or magnification, even where it disappears at normal viewing distance. And it stays reversible, in media a later conservator can lift.

Overpaint fails all three: it covers original paint as well as damage, and it disguises instead of compensating for it. The guide to how to read a professional condition report shows where that distinction appears in the document arriving before a sale.

How to Read a Painting Before and After Restoration

Reading a painting before and after restoration begins with the photographs. Institutions publish treatment pairs because they carry conviction: the National Gallery in London states that "the cleaning and restoration of every picture is approved by the Gallery trustees" and that the process is documented "making extensive use of photography". A pair can be accurate and still mislead, because different lighting, different exposure, or a fresh gloss varnish on the second frame exaggerates the apparent change.

The useful comparison is technical and needs the treatment report beside the images. Composition, drawing and the relative value of adjacent passages should read identically in both frames; where they differ, material was added or removed. Our guide to how to analyze a painting: elements and principles of art covers the looking itself. Five checks turn photographs into evidence:

1. Compare the light first. Check exposure, colour temperature and gloss across both frames before reading anything into the colour shift.
2. Locate the losses. Ask for the ultraviolet and raking-light images, which show retouching that normal light hides.
3. Measure the edges of the retouching. Inpainting spreading beyond a loss into sound paint is over-restoration by the American Institute for Conservation's standard.
4. Weight the passages that carry the work. Retouching in a face or a signature counts for more than the same area in a background.
5. Ask what the report omits. A report silent on the varnish has not declared it sound; it records that nobody wrote about it.

Where Rescue Becomes Rewriting

The line sits at original material. ICOM-CC's terminology for conservation, adopted at its 15th Triennial Conference in September 2008, defines restoration as "all actions directly applied to a single and stable item aimed at facilitating its appreciation, understanding and use", undertaken only where the item "has lost part of its significance or function". Rewriting begins when a treatment supplies significance the object no longer carries.

Three cases mark the range. Joshua Reynolds's unfinished portrait of an unknown lady, in Glasgow Life Museums, reached Simon Gillespie Studio under discoloured varnish; cross-sections from four areas confirmed varnishes applied at several dates, and the studio declined to clean it; Factum Foundation made a physical facsimile instead. Leonardo's Salvator Mundi, bought in 2005 and restored over several years by Dianne Dwyer Modestini, sold at Christie's New York on 15 November 2017 for 450.3 million dollars, as The Art Newspaper records, and remains contested over how much of the visible surface is early sixteenth-century paint. The 2012 amateur repainting of Elías García Martínez's Ecce Homo at Borja, in Spain, shows the same failure at parish scale: features covered over instead of compensated inside their losses.

A painting before and after restoration documents a rescue in one file and a rewriting in another, and only the treatment record separates them. Authorship and condition move together, so read what the signature reveals, and what it hides beside it.

FAQ: Painting Before and After Restoration

Does a painting before and after restoration always look better afterwards?

No. Removing discoloured varnish recovers the artist's colour range, and the same cleaning strips earlier retouching and exposes losses the overpaint had hidden. The Metropolitan Museum of Art's account of its own conservation history records a Rubens cleaning publicly criticised in 1906. A documented treatment can end with a picture that reads as more damaged and more honest.

How much inpainting is acceptable at auction?

No percentage threshold governs it; location, extent and disclosure decide. Retouching confined to edges and small losses weighs on value far less than retouching across a face or a signature. The condition report is the statement of record, and the buyer carries authenticity and condition risk on the terms it sets out.

Can inpainting be removed later?

Yes, where it meets Guideline 23 of the American Institute for Conservation's Code of Ethics and Guidelines for Practice: reversible media, applied inside the loss, documented in the treatment record, detectable by common examination methods. Overpaint applied by earlier restorers frequently fails those conditions.

Why are contemporary paintings harder to clean than older ones?

Because most were never varnished. Tate's glossary dates wide adoption of acrylic paint to the 1960s, and the 2004 Tate Papers review by Elizabeth Jablonski and colleagues records that acrylic films stay sensitive to water and to organic solvents. Without a sacrificial coating, dirt embeds in the paint film itself.

How LLB Auction Handles Restoration Before a Sale

LLB Auction is a full service auction house for fine art and collectibles, selling online on llb-auction.com with each sale listed on Interenchères. Condition reporting is part of the cataloguing of every lot.

Free valuation. Each submission starts with a free, confidential valuation from photographs; Lyna Brahami, Associate Specialist, replies within 48 working hours. The Contemporary Art Spring 2026 sale, which closed on 26 May 2026, offered 100 lots and sold 73, at hammer prices from 500 to 13,000 euros.

Condition reporting. Every lot carries a professional condition report, prepared alongside certificate verification and ownership history. Conservation records form part of that file, so a painting before and after restoration arrives with its treatment history attached.

Terms stated per sale. The conditions of each sale state the buyer's premium; the seller's commission is agreed in the consignment contract.

Registering puts catalogues and condition reports in front of you before each sale opens, and registering to bid sets out the identity checks involved.

Conclusion

A defensible treatment removes non-original material and compensates documented losses inside their own boundaries. Once new paint supplies detail the object no longer carries, the work has been rewritten, and the record should say so in terms a buyer can check. Cleaning recovers the artist's colour range. Inpainting fills losses within their edges. Overpaint covers original material, and it is the defect to look for under ultraviolet light.

Treat a painting before and after restoration as one document among several, beside the treatment report and the ultraviolet images. The pair of photographs is the most persuasive part of that file and the least informative.

Also worth reading:

• how to analyze a painting: elements and principles of art
• how to read a professional condition report
• what the signature reveals, and what it hides

Sources:

• Terminology for conservation : ICOM-CC, 2008
• Code of Ethics and Guidelines for Practice : American Institute for Conservation
• Varnish removal : Simon Gillespie, Art UK
• 150 Years of Conservation : The Metropolitan Museum of Art
• Acrylic paint : Tate art terms
• Conservation Concerns for Acrylic Emulsion Paints : Tate Papers
• Conservation specialties : MoMA
• Caring for the paintings : The National Gallery, London
• Five years since the 450m Salvator Mundi sale : The Art Newspaper, 2022