Art Restoration: The Definitive Glossary of Art Materials & Techniques

Understanding the language of conservation is essential for appreciating the care and expertise involved in preserving artworks and cultural objects. This glossary has been created by our conservation team to explain the key terms, techniques and principles used in professional conservation practice. Each term defines a specific process, material or concept that a conservator may reference when assessing, treating or caring for an artwork.

Our definitive glossary of art brings together an extensive range of traditional and contemporary techniques. Designed as both a practical reference for conservators, artists, collectors and an educational resource for those interested in material history, this glossary traces how creative media have evolved, from natural pigments to synthetic polymers. This series also covers:

• Paintings
• Drawings
• Print Making
• Decorative Objects
• Fine Furniture
• Art Historical Terms

Whether you are a collector, museum professional or simply interested in how artworks are preserved for future generations, this art restoration glossary provides clear insight into the terminology of our field. It also supports transparency by helping clients understand the conservation processes described in our treatment reports and recommendations.

Above: one of our conservators treating an oil painting with the precise application of conservation grade pigments

Archival

Conservation grade storage or display material for ongoing preservation. Archival materials are pH neutral, preventing chemical reactions that cause yellowing, brittleness or deterioration. They include conservation grade papers, boards, mounts, boxes and protective enclosures made from stable, non-reactive components. Using archival materials in framing, storage and display helps ensure artworks remain protected from light, humidity and pollutants.

Read more about our conservation framing services here.

Analysis

Scientific examination of an artwork’s materials and structure to gain insight into its composition and condition. Analytical techniques can identify materials and previous restoration campaigns, helping conservators make informed treatment decisions. Methods may include microscopy and ultraviolet fluorescence. Analysis supports ethical conservation by ensuring any intervention is based on accurate material understanding.

You can find out more about painting analysis here.

Anoxic Storage

Oxygen free or low oxygen environment used to prevent the biological decay and chemical oxidation of artworks and historic objects. By reducing or removing oxygen, this method inhibits mould growth, insect activity and corrosion, particularly in organic or metal-based materials. Anoxic storage is often used in museums and conservation studios for the long-term preservation of sensitive items such as textiles, paper or archaeological artefacts. It is a preventive conservation technique that stabilises materials without direct intervention.

Backing Board

Protective panel placed behind artworks within frames to provide physical support, stability and environmental buffering. Backing boards help protect artworks from dust, pollutants and fluctuations in humidity and temperature, while also preventing damage from handling. They are typically made from archival, acid-free and pH-neutral materials such as conservation board to ensure they do not off-gas harmful substances. A properly fitted backing board is an essential component of preventive conservation, contributing to the long-term preservation of framed artworks.

Above: an oil painting damaged by swimming pool water, before and after restoration by our easel painting conservators

Blanching / Bloom

Clouded, white appearance on the surface of a varnished painting, typically caused by trapped moisture, mould growth or humidity. This hazy film can make the varnish appear milky and dull, obscuring the colours and depth of the original paint layer beneath. Blanching often occurs when moisture becomes trapped between the varnish and paint layers. In conservation, blanching is carefully treated through varnish removal and replacement, restoring the painting’s clarity and original finish.

See an example above. You can find out more about moisture damaged paintings here.

Binding Medium

Substance that holds pigment particles together and allows them to adhere to a surface when applied as paint. The binding medium can determine texture, drying time and durability, as well as how it responds to ageing and cleaning. Common examples include linseed oil in oil paints, egg yolk in tempera, gum arabic in watercolours and acrylic polymers in modern paints. Understanding the binding medium is essential in conservation, as it influences the choice of solvents, consolidants and cleaning methods used to safely treat an artwork without damaging its original materials.

Bonding

Process of re-adhering separated, broken or detached pieces of an artwork or object to restore its structural integrity. This treatment is commonly applied in the conservation of ceramics, sculptures, frames and mixed-media artworks, where fractures or breaks have occurred. Conservators use reversible, conservation-grade adhesives that provide strength while allowing future re-treatment if required. Bonding must be carried out with precision to ensure that joins are stable, visually unobtrusive and chemically compatible with the original materials.

See a case study about bonding a smashed vase here.

Above: our conservator treating a damaged porcelain vase

Capillary Action

Movement of moisture through porous materials such as paper, canvas, plaster or wood via microscopic channels. In artworks, capillary action can lead to tide lines, staining, discolouration or paint lifting, especially when exposed to water damage, floods or high humidity. Understanding and controlling capillary action is crucial in conservation, as treatments often focus on stabilising moisture levels and reducing water migration to prevent further deterioration.

Read more about water damaged paintings and water damaged paper restoration.

Cleaning Tests

Preliminary trials carried out by conservators to determine the safest and most effective cleaning methods for an artwork before treatment begins. These controlled tests assess how the surface materials (paint, varnish, paper, etc.) react to different solvents, solutions or mechanical cleaning techniques. By observing small test areas, conservators can evaluate potential risks. Cleaning tests ensure that all treatments are minimally invasive, fully reversible and tailored to the artwork’s specific condition, structure and materials.

You can find out more about the process of cleaning an oil painting here.

Cleavage

Separation of paint or ground layers from their underlying support, often occurring in paintings on canvas. This condition is typically caused by environmental stress or from aged and weakened binding media. It can also be produced by physical impact, fire or water damage. If untreated, it may lead to flaking, paint loss or further structural instability.

Consolidation

Process of securing flaking, lifting or fragile areas of an artwork to prevent further loss or deterioration. This treatment is often applied to paint layers, gilding, plaster or other delicate surfaces where materials have become detached from their support. Conservators use fine injections of adhesive or controlled heat to re-adhere the lifting areas. The goal of consolidation is to stabilise the artwork structurally while preserving its original appearance and texture. When carried out correctly, it halts active deterioration and provides a secure foundation for any subsequent conservation treatments, such as cleaning or tear repairs.

See an example below. Read more about flaking and unstable paintings here.

Above: a modern oil painting with areas of paint loss and cracking, before and after treatment by our conservators 

Cockling

Distortion of paper, card or similar sheet materials. Cockling is typically caused by fluctuations in moisture or humidity, when paper absorbs water unevenly, its fibres swell at different rates, leading to ripples or raised areas across the surface. Cockling can also occur from historic water damage as well as unsuitable mount or framing materials. This deformation may affect both the aesthetic and structural stability of an artwork. In conservation, treatments for cockling include humidification and flattening under controlled conditions, maintaining the integrity of the original paper fibres.

Read more about water damaged paper artworks here.

Condition Report

Comprehensive written and photographic record of an artwork’s physical state, created before and after conservation treatment. This document identifies structural issues, surface damage, environmental wear and areas of past restoration, providing a benchmark for comparison over time and an informative document for the owner or custodian. Condition reports are essential for insurance, transport, sales, exhibition loans and treatment planning, ensuring that any changes to the artwork are fully traceable. Our conservators include high-resolution images, material observations and recommendations for preventive care.

See more about artwork condition reports here.

Conservation Grade

Reference to materials, methods or products that meet recognised standards for the preservation of artworks and objects. Conservation grade materials are stable, non-acidic or low in pH, ensuring they do not cause deterioration or discolouration over time. Examples include acid free papers, pH neutral mounts, UV-filtering glazing and reversible adhesives. These materials are tested for long term stability and are used in framing, storage, transport and treatment to safeguard artworks from environmental or chemical damage. In professional practice, using conservation-grade materials supports ethical, preventive conservation and aligns with the standards set by organisations such as ICON.

Above: our conservator treating a watercolour painting

Conservator

A trained professional who preserves and restores artworks, objects and cultural heritage using established ethical and technical standards. Conservators combine scientific knowledge and precise skills to stabilise and protect artworks while respecting their historical integrity. Their work follows strict professional guidelines, such as those set by ICON (Institute of Conservation) which emphasise minimal intervention, reversibility, documentation and respect for original materials. A conservator may specialise in specific fields such as paintings, paper, textiles or objects, ensuring that each artwork receives expert, tailored care for its long-term preservation.

Click here to read more about our conservation team.

Cross-section Analysis

Microscopic examination of uninvasive samples taken from an artwork to study the structure and composition of its layers. Conservators can view the paint, ground, varnish and dirt layers in sequence under high magnification.

You can find more about technical analysis of paintings here.

Deacidification

Process of neutralising harmful acids present in paper, textiles or other materials. Acidity can result from surrounding materials, pollutants or natural ageing of fibres, leading to brittleness, yellow / brown discolouration and eventual structural breakdown. During acid removal, conservators apply solutions that stabilise the pH and lift the staining and contaminants. This treatment is an essential part of paper and textile conservation, ensuring long-term preservation without altering the original appearance of the artwork, design or document.

See an example below. Read more about acid stain removal for paper artworks here.

Above: an acid damaged portrait of Queen Elizabeth II, before and after treatment by our paper conservator

Deformation

Distortion, warping or bending of materials leading to visible irregularities such as bulging, sagging, ripples or misalignment. It can occur when materials expand and contract at different rates or stress from handling, framing, an accidental impact or environmental instability. In conservation, treatment focuses on stabilising the artwork, relieving stress and carefully flattened or reshaping the affected area using controlled support, always ensuring minimal intervention and a stable result.

Desiccation

Excessive drying or loss of moisture within materials, leading to shrinkage, cracking or structural weakness. This condition can affect a variety of artworks and materials, particularly when exposed to low humidity or rapid environmental fluctuations. As materials lose internal moisture, they contract unevenly, causing paint to flake, supports to warp or surfaces to become brittle. Desiccation is prevented through careful environmental control with an appropriate level of humidity for the artwork or object. The restoration options include bespoke consolidation and stabilisation treatments.

Ethical

Referring to the principles and professional standards that guide all conservation work, ensuring that treatments are carried out responsibly and respectfully toward the artwork’s integrity and history. Ethical conservation practice is based on key values such as minimal intervention, reversibility and full documentation. These principles ensure that no original material is altered unnecessarily and that the artwork’s authenticity is preserved. Conservators follow established ethical frameworks set by professional bodies such as ICON (Institute of Conservation) and IIC (International Institute for Conservation) to maintain consistency, accountability and long-term preservation across all disciplines.

Above: the removal of a canvas painting from a frame

Filling / Infilling

The process of replacing areas of loss on a painting, object or decorative surface to recreate an accurate texture before retouching colour. Fill materials are carefully selected to match the surrounding surface in texture, while remaining reversible and ethical for the treatment of the artwork. Common conservation fillers include chalk, gesso or synthetic compounds mixed with binders. The purpose of filling is to restore the visual and structural continuity of the artwork without obscuring the original materials. Once the fill is shaped and textured, it provides a suitable base for the reapplication of colour or surface tone during later restoration stages.

Finish

Final surface layer or coating of an artwork, which defines its appearance, texture and visual depth. The finish may include a varnish on a painting, the glaze on a ceramic or the polish on a wooden object. It serves both aesthetic and protective purposes, enhancing colour and sheen while shielding the underlying material. Over time, finishes can degrade, yellow or become cloudy, affecting the overall appearance. In conservation, finishes may be examined and treated through cleaning or selective removal and replacement.

Foxing

Brown or reddish spots and freckles on paper or textiles. Commonly seen on paper artworks, prints, maps and books. Foxing is usually caused by a combination of mould growth, metal impurities and exposure to humidity or poor storage conditions. These stains can vary in intensity and distribution, sometimes appearing as light speckles or large discoloured patches. In conservation, foxing is treated through carefully controlled cleaning, washing or reduction techniques, depending on the stability of the underlying material and media.

See an example below. Read more about the removal of foxing on paper here.

Above: an antique print damaged by foxing growth, before and after restoration by our paper conservator

Fixative

Specialised spray or solution applied to artworks to stabilise friable or powdery media, such as charcoal, chalk, pastel or graphite. Fixatives help to reduce smudging and loss of pigment from the surface, forming a delicate binding film over the artwork. However, their use in conservation is approached with caution and ethical consideration. Inappropriate application of fixatives can darken colours, alter surface texture or change the visual quality of the work. When used, any fixatives are selected for their reversibility, stability and compatibility with the original materials. Alternative preventive methods, such as protective mounts, glazing and controlled environments, are often preferred as a less invasive way to preserve these fragile materials safely.

Flaking

Detachment or lifting of paint or other surface layers from their underlying support, such as canvas. Flaking is often caused by environmental fluctuations, ageing of the binding media, tears and break lines, accidental damage or impact from fire and water. Flaking poses a significant risk of paint loss if not stabilised promptly. Conservators address flaking through precise treatments using reversible adhesives introduced beneath the lifting areas. They will also reapply saved pieces that have fallen away from the surface whenever possible, to minimise any need for visual intervention. Preventive measures, including stable humidity and temperature control, are essential to minimise future flaking and preserve the integrity of the artwork.

Read more about flaking paintings here.

Friable

Surface or medium that is powdery, unstable or easily detached, often found in artworks made with pastel, charcoal, chalk or degraded paint layers. Friability occurs when the binding medium has weakened, leaving the pigment particles loose and vulnerable to loss through touch, vibration or movement. This condition can lead to visible dusting or fading over time. In conservation, friable media are treated with minimal intervention. Careful handling and controlled environmental conditions are essential to preserve the delicate surface structure of friable artworks.

Ground Layer

Preparatory coating applied to a support (canvas, panel, etc.) before applying paint, creating a smooth, stable and absorbent surface for the paint layers above. The ground provides texture, colour balance and structural stability, helping the paint adhere evenly and preventing it from sinking into the support. Traditional grounds are made from materials such as gesso (a mixture of chalk or gypsum with animal glue) or ready made primer. The composition and colour of the ground can influence the overall tone and appearance of the finished artwork. In conservation, understanding the ground layer is essential for diagnosing issues such as cracking and paint loss, as damage often originates where this layer separates from the support.

Above: one of our conservators conducting image reintegration treatment through a magnified lens

Humidity Control

Management and stabilisation of moisture levels in the air to protect artworks and objects from deterioration. Fluctuations in relative humidity (RH) can cause materials such as canvas, wood, paper and paint to expand and contract, leading to warping, cracking, cockling or mould growth. Effective humidity control involves maintaining a consistent RH level depending on the material’s needs, along with stable temperature conditions. Conservators achieve this through climate-controlled environments, microclimate enclosures and monitoring systems. Maintaining stable humidity is a key element of preventive conservation, helping to ensure the long-term preservation and stability.

ICON (Institute of Conservation)

The UK’s professional body for the conservation and restoration of cultural heritage. ICON promotes ethical practice, professional standards and public understanding of conservation, ensuring that artworks and historical objects are treated responsibly and transparently. The organisation upholds principles such as minimal intervention, reversibility and full documentation, providing a framework for decision-making within the profession.

Image Re-integration

Precise retouching of lost or damaged areas of paint or detail to restore the visual unity of an artwork. This process, also known as retouching, is carried out with a minimal and reversible approach, ensuring that only areas of loss are addressed without altering the artist’s original work. For easel paintings, conservators use finely matched pigments and reversible media such as watercolours or synthetic resins, applied within isolating layers of varnish. The goal of image re-integration is to maintain the visual impact with ethical responsibility, allowing the artwork to be viewed in a cohesive way following restoration.

Find out more about flaking paint restoration here.

Lining

The process of attaching a weakened or damaged artwork to a new support to provide additional strength and stability. In painting conservation, canvas lining involves adhering the original canvas to a secondary one using a suitable adhesive, ensuring that tears, deformations or weakened fibres are supported without adversely affecting the surface. In paper conservation, lining refers to attaching the artwork to a thin, acid-free support sheet, often made from Japanese tissue or other conservation-grade material, to reinforce fragile or torn areas. Modern lining techniques prioritise minimal intervention, reversibility and the use of stable, non-invasive materials that preserving both the structure and authenticity.

Above: a mould damaged painting restored by our conservation team 

Mould Remediation

Controlled removal and neutralisation of fungal growth on artworks, including paintings, paper, furniture and decorative objects. Mould can develop when artworks are exposed to high humidity, water or poor air circulation, leading to staining, discolouration and the breakdown of organic materials such as canvas, paper and pigments. Conservators work under strict safety and environmental controls, using dry surface cleaning bespoke treatments to eliminate spores without damaging the original material. Preventive measures, such as humidity regulation, air filtration and proper storage, are essential to ensure that mould does not reappear.

See an example above. Read more about mould restoration for paintings and paper.

Light Damage

Fading, discolouration or structural deterioration of artworks caused by prolonged exposure to sunlight or strong artificial lighting. Sensitive materials such as watercolours, ink and organic pigments are particularly vulnerable, as light can break down chemical bonds and alter colour stability over time. Unlike some other types of deterioration, light damage is cumulative and irreversible, meaning that even low levels of exposure can cause long-term change. In conservation, preventive measures include using UV-filtering glazing, low-intensity lighting and controlled display durations.

Learn more about UV protection for artworks here.

Microscopy

Magnification to examine the materials of an artwork in detail. Conservators observe paint layers, fibres, pigments and signs of deterioration that are invisible to the naked eye. Microscopy is an essential diagnostic tool in conservation, helping to guide treatment decisions. When combined with other analytical methods such as cross-section analysis or UV fluorescence, it provides valuable insight. Microscopy is also used during treatments that require a surgical level of precision, such as repairing a torn painting.

Learn more about how we examine artwork materials here.

Minimal Intervention

Ethical principle of carrying out only the treatments necessary to stabilise and preserve an artwork, while avoiding any alteration to its original materials or appearance. This approach ensures that conservation work remains respectful of the historical, cultural or artistic integrity. It is a core standard in professional conservation practice, supported by organisations such as ICON (Institute of Conservation) and the IIC (International Institute for Conservation), forming part of the broader framework of responsible, ethical care.

Solvent Gel

Thickened cleaning solution used in conservation to deliver solvents in a precise and controlled manner. By suspending a solvent within a gel, conservators can limit the spread and penetration of the liquid. Solvent gels are particularly useful for varnish removal, surface cleaning and stain reduction, as they allow for longer contact times and greater accuracy on delicate surfaces. The composition of a solvent gel can be adjusted to the sensitivity of the artwork.

Above: our conservator cleaning a Lladro figurine

Off-Gassing

The release of volatile organic compounds or other chemicals from materials used in framing, storage or display. These emissions can arise from adhesives, paints, plastics, foams and certain wood products. They react with artworks and can cause discolouration, tarnishing or surface degradation. Off-gassing is particularly harmful in enclosed environments, where vapours can accumulate and interact with sensitive materials. In conservation, the use of archival, conservation-grade and pH-neutral materials helps prevent off-gassing.

Read more about conservation grade framing materials here.

Overpaint / Overpainting

Non-original paint applied during a past restoration or alteration, often used to cover areas of loss, damage or discolouration. Overpaint can obscure an artist’s original work and may differ in texture, colour or skill. It is usually detectable under UV light. In conservation, the identification and careful removal or reduction of overpaint are carried out when appropriate, using controlled methods. The goal is to restore visual balance while preserving the authenticity and integrity of the original artwork.

Paint Layer

The visible, coloured layer of an artwork composed of pigments bound together by a medium, such as oil, acrylic, tempera or gum arabic. This layer forms the image itself and is applied over a ground or primed surface, which provides adhesion and stability. In art conservation, understanding the material composition and condition of the paint layer is essential for selecting appropriate treatments while preserving the original artistic intent.

Pollutants

Airborne substances that can chemically or physically damage materials. Common pollutants include soot, smoke, sulphur compounds and volatile organic compounds, which may enter from outdoor air or be emitted by building materials and display cases. They may also be present due to a recent or historic house fire and exposure to an open fireplace or nicotine fumes. Over time, pollutants can cause dark discolouration, staining or weakening or materials. The effects of pollution, such as smoke damage, are addressed through sensitive surface cleaning followed by a varnish removal if it is further embedded.

Read more about fire damaged paintings here. See an example from our studio below.

Above: a painting restored by our team following exposure to smoke during a house fire

pH Neutral

Materials with a balanced acidity level that are safe for long-term preservation of artworks and archival objects, this is usually around pH 7. The pH-neutral materials do not release acids that can cause yellowing, embrittlement or chemical decay. Common examples include acid-free papers, boards, adhesives and mounts used in framing. Maintaining pH neutrality helps to stabilise artworks, reducing the risk of acidic degradation.

Pigment

Finely ground natural or synthetic colour. Pigments are mixed with a binder or medium such as oil, egg, or acrylic to form a paint that adheres to a surface. Natural pigments can be derived from minerals, plants or animals, while synthetic pigments are industrially manufactured. Each pigment has unique chemical properties, meaning that different colours can fade, darken or decay at varying rates depending on factors such as light exposure, humidity or chemical reaction. In conservation, identifying the pigments used in an artwork helps determine appropriate cleaning methods, environmental conditions and treatment to ensure long-term preservation.

Read more about the creation and preservation of ultramarine blue and verdigris green.

Preventive Conservation

The practice of protecting artworks and cultural objects by preventing damage before it occurs, rather than intervening after deterioration has taken place. This proactive approach focuses on environmental management, safe handling, appropriate storage and the use of stable, conservation-grade materials. By controlling factors such as light, humidity, temperature and pollutants, preventive conservation reduces the need for future restoration and extends the lifespan of artworks. It is a fundamental principle of ethical conservation.

Reversibility

The ethical principle that all conservation treatments should be capable of being safely undone without causing harm to the original artwork. This ensures that future conservators can re-treat or revise previous interventions as materials, techniques and scientific knowledge evolve. Reversibility supports transparency, accountability and long-term preservation. It is closely linked with the principles of minimal intervention and documentation, which together protect the integrity and authenticity of the artwork.

Above: the restoration of a damaged detail on the surface of a damaged painting 

Solvent Testing

Assessing different cleaning materials and solvent mixtures to determine the safest and most effective method for treating an artwork. Before any cleaning takes place, conservators perform controlled tests on small, inconspicuous areas to observe how paint layers, varnish and surface coatings respond. This ensures that the chosen solvent does not cause colour change or loss of original materials. The goal is to find a stable cleaning approach, tailored specifically to each artwork.

Stabilisation

Halting or slowing active deterioration to prevent further loss or structural damage. This treatment focuses on securing fragile materials, controlling environmental conditions and addressing the underlying causes of decay rather than altering the artwork. Stabilisation treatments depend on the specific materials and current condition of the artwork or object. It is often the first stage of treatment, providing a safe foundation for any further restoration work.

Stretching

Re-tensioning a canvas artwork onto its stretcher or frame to ensure a flat, stable surface. Over time, canvas can sag, distort or lose tension due to environmental changes, age or handling. Conservators carefully adjust or replace tacking edges and stretcher keys, tightening the canvas gradually to restore even tension without placing stress on the paint layer. In cases of significant slackening, the artwork may be temporarily removed and re-stretched under controlled conditions. Proper stretching is essential for maintaining the structural integrity and visual presentation of a painting, preventing further cracking or deformation.

Read more about the restoration of loose paintings.

Surface Clean

Removal of surface dirt, dust and contaminants that rest on top of a varnish or protective layer. This preliminary stage of treatment improves the artwork’s appearance and stabilises its condition without disturbing the original paint or varnish beneath. Surface cleaning is performed using soft brushes, dry sponges or specially formulated aqueous and solvent-based solutions, selected through prior cleaning tests to ensure safety and compatibility. The process can remove soot, smoke residue and atmospheric grime, revealing the true colours and details of the artwork. This may be followed by a varnish removal treatment to remove further discolouration, if deemed necessary.

See an example below. Read more about how conservators clean paintings here.

Above: a painting with subtle discolouration, before and after surface cleaning treatment

Substrate / Support

Base material that forms the foundation of an artwork, providing a structure for the colour or decoration to be applied upon. Common supports include canvas, wood panels, paper, copper, plaster or textile. Each support has distinct properties that influence the artist’s technique and the artwork’s long-term preservation needs. In a conservation studio, understanding the nature of the substrate is crucial for diagnosing and treating issues like cracking, warping or delamination.

Tacking

Securing or replacing the tacks or staples along the edges of a canvas to ensure it remains tightly attached to the stretcher or strainer. Over time, tacks can become loose or corroded, leading to slackening or distortion of the canvas, which may cause stress on the paint layer. During conservation, tacks are carefully removed, cleaned or replaced with stainless steel or copper alternatives to prevent future corrosion. Correct tacking maintains even canvas tension and structural stability, supporting the long-term preservation and presentation of the artwork.

Tear Repair

Restoring torn, punctured or split areas of a painting or work on paper to regain structural integrity and visual cohesion. Tears can occur from impact, handling, environmental stress or age related deterioration. If left untreated, tears may worsen or lead to flaking paint and loss of details. In canvas conservation, tear repair involves realigning fibres, inserting fine threads and reinforcing the area with a minimal approach, conducted under microscope. For works on paper, conservators may use Japanese tissue and wheat starch paste to rejoin fibres invisibly. The goal of tear repair is to stabilise the damage with minimal intervention, preserving both the strength and appearance of the original material.

You can find out more about repairing torn paintings here.

Toning

Subtly adjusting colour or brightness to visually integrate areas of restoration with the surrounding original surface. Toning is often carried out after filling or retouching, helping to reduce visual distractions. In ethical conservation practice, toning is performed with a minimal and reversible approach, guided by the principle of preserving the artist’s original intent.

Above: the fine details of a gilt frame cleaned with a small swab

Treatment Proposal 

Document outlining the recommended conservation approach for an artwork, prepared and discussed with the client before any work begins. It details the artwork’s condition, proposed treatments and materials to be used. The treatment proposal ensures that the client fully understands the options available and that all decisions are made transparently and collaboratively. This stage allows the conservator to explain the ethical considerations, potential risks and expected outcomes, ensuring that the chosen course of action aligns with professional conservation standards and the client’s expectations.

UV Fluorescence

The use of ultraviolet (UV) light to examine the surface of an artwork, revealing details that are often invisible under normal lighting. When exposed to UV light, certain materials, such as varnishes, pigments and adhesives emit characteristic colours or patterns of fluorescence. This allows conservators to detect previous restoration work, retouching or areas of alteration. UV fluorescence is a non invasive diagnostic technique commonly used to build an understanding of an artwork’s history, structure and treatment needs.

Varnish

Transparent protective coating applied to the surface of oil paintings and some other artworks to enhance colour saturation and provide a uniform finish. Traditionally made from natural resins such as damar or mastic and more recently from synthetic resins, varnish serves both an aesthetic and protective function, shielding the paint layer from dust, moisture and environmental pollutants. Over time, varnish can yellow, darken or become cloudy, altering the appearance of the artwork.

Varnish Removal

Reducing or fully removing an aged or deteriorated varnish layer from the surface of a painting. Over time, varnish can yellow, darken or become cloudy, obscuring the artist’s original colours and tonal balance. Conservators perform varnish removal only after thorough solvent and cleaning tests, ensuring the paint layer beneath is stable and unaffected. The procedure is carried out using hand-rolled cotton swabs allowing precise and controlled application. Once removed, the painting’s surface is often re-varnished with a stable, reversible resin to restore clarity and protection. Varnish removal is a highly skilled treatment that enhances visual legibility while preserving the authenticity of the original artwork and should only be conducted by a trained conservator.

See an example of varnish removal below. Learn more about discoloured painting restoration here.

Above: an antique painting before and after surface cleaning and removal of discoloured varnish 

Contact Our Team

As part of our service we offer a nationwide collection and delivery service as well as information on worldwide shipping to our studio. E-mail us via [email protected] or call 0207 112 7576 for more information.