One of the museum’s most important tasks is to ensure that the works of art in our holdings are maintained in the best possible condition.

What is art conservation?

Our conservators treat, document, and study the museum’s collections of paintings, paper drawings, textiles, decorative arts and design, installations, and electronic media.

The museum’s department of conservation has the principal responsibility for taking care of the objects in the museum’s collections. Among other things, this entails ensuring that the conditions during exhibitions, in storage facilities, or during transport help extend the lifetime of the works of art as much as possible.

When conservators have to work with mold-infested material, special work outfits, with gloves, suits and masks, are in order.
Photo: Børre Høstland / Nasjonalmuseet

Sculptures and Installations

The National Museum’s collections of sculptures and installations encompass everything from “classical” stone and bronze sculpture to modern sculptures and installations.

Many of the National Museum’s more recent sculptures and installations use unconventional materials and methods. Some of the works also include kinetic elements.

A quick guide to conservation of sculptures and installations

  • 1. Assessing the condition

    Is the object undergoing a process of degradation? Has any new damage occurred? We document the condition of the piece in text and images and repair any damages that may have occurred, so that the sculpture is stabilized. Sometimes it may be necessary to analyse the object in order to identify the materials or techniques the artist has used, so that we may choose the optimal method of conservation.

  • 2. Establish guidelines

    We establish guidelines for how the objects are to be handled, displayed, stored, and packaged, so that its lifetime may be extended as much as possible.

  • 3. Correct treatment

    Many sculptures and installations contain industrially manufactured items, machines, or other gadgets that have been modified and repurposed. It is therefore essential to consult experts from other fields when the conservator’s own expertise falls short, for example when repairing neon lights, compressors, or cooling elements.

  • 4. Documentation

    In addition to combating the three main threats against the lifetime of the object, namely chemical, mechanical, and biological impacts, the conservator who works with sculptures and installations must actively document these objects.

Particularly when working with installations, the surroundings and the relationships between the individual parts are at least as important as the individual parts themselves. Discussions with the artists themselves provide vital information about how the given sculpture or installation should be displayed, in addition to providing us with useful knowledge about the materials and techniques the artist has used.

Decorative Arts and Design

The National Museum’s collections of decorative arts and design span a period of time from antiquity until today.

The fields of decorative arts and design encompass numerous disciplines and an even greater variety in the materials used. The National Museum’s collection includes items from a wide range of genres, such as jewellery and objets d’art made from precious and base metals; wood and ivory carvings; glass objects and ceramics; furniture, mirrors, and other furnishings; and industrial design in all kinds of materials and styles.

Most of the disciplines build on traditional arts and crafts, but more recent items in the collection often blur the disciplinary boundaries in regard to material, technique, and style, so that the boundaries are not as clear-cut.

Maren Midtdal and Christina Iversen are working with jewelry made of horse hair.
Photo: Frode Larsen / Nasjonalmuseet

Conservators who work with decorative arts and design are keenly interested in materials.

  • What is the material’s chemical composition?
  • How is the material produced?
  • How can it be adapted?

In order to make qualified decisions in regard to either so-called preventive or active conservation, the conservator should have in-depth knowledge about such material technology.

Photo: Frode Larsen / Nasjonalmuseet

In order to determine how best to take care of an object, the conservator must analyse the object in order to identify the materials and techniques.

Despite the staggering variation in materials and forms, taking care of objects can in general be sorted into two categories: preventive conservation and active (or interventionist) conservation. Preventive conservation pertains to removing or minimizing any factor that could damage the objects, while active conservation entails that the conservator works directly on the object, usually in order to “stabilize” it. 

Types of damage for decorative arts and design

Chemical damage

When silver tarnishes, this is the result of a chemical reaction where sulphur in the air reacts with the silver alloy. In that case, the conservator will attempt to reduce the contact with sulphur by storing the silver object along with a substance that bonds more quickly with sulphur than the silver alloy does, or wrap the object in such a way that keeps oxidization to a minimum. By contrast, polishing the object only serves to remove the bluish-black surface, even as it provides the sulphur with a “fresh” surface to bond with.

Mechanical damage

A vase that falls on the floor and breaks is an example of a mechanical damage. In order to try to prevent such damages, the conservator must make plans to ensure that the handling and transport of objects is as gentle as possible.

Biological damage

Biological damages refer primarily to mould and insects. Water damages and high levels of humidity over a period of time act as catalysers that accelerate such damages. It is the conservator’s responsibility to ensure that the humidity surrounding the object does not become too high.

Painting Conservation

The painting conservators at the National Museum are responsible for around 6,500 paintings, ranging in time from the fifteenth century until the present day.

The collection consists mainly of Norwegian paintings on canvas, but also includes important European paintings, icons, and portrait miniatures from various eras, as well as an ever-expanding collection of modern and contemporary works.

The materials and techniques used in these works vary greatly.

The collections include works where the artist has used binding agents such as oil, acryl, egg tempera, glue, PVA dispersions, wax, natural and synthetic resins, and house paint, but also foodstuffs such as gelatine.

Painting surfaces range from primed canvases and wood panels to fibreboards, metals, and plastics.

Photo: Nasjonalmuseet / Annar Bjørgli

All materials age, whether in older or modern art. Such aging and degradation will typically manifest itself in the artwork changing its appearance, often over the course of many years, for example when a pigment fades or varnish yellows. 

When taking care of such a diverse collection, there are a many different factors that have to be taken into consideration, but the aim will always be to choose conservation methods and materials that ensure the objects are preserved in the best possible condition over the longest possible stretch of time.

Every conservation process begins by documenting the condition of the work. This is followed by a thorough examination of the materials and techniques that have been used. 

Photo: Nasjonalmuseet / Andreas Harvik 

This usually entails inspecting the painting’s surface with a stereo microscope and using lights of varying wavelengths, such as ultraviolet and infrared radiation and X-rays. Conservation may also involve taking small samples of the paint and studying the layering, pigments, binders, and surface material under a microscope with a high degree of magnification, often in the form of a cross-section.

More advanced instruments make it possible today to identify the chemical elements and organic compounds that were originally used in the sample. Interviews with artists represent another key source of information about contemporary art. 


The National Museum possesses a large collection of paper-based materials, including around 50,000 drawings and prints.

The National Museum also owns more than 300,000 architect’s drawings, as well as a large photography collection. The collection ranges from the late fifteenth century until the present day. Currently the museum employs three paper conservators to look after its sizeable and varied collection.

Paper is an intriguing material. However, people often forget how many different types of art are actually made on paper, such as pencil sketches and watercolours; pastels and gouache; prints; drawings in charcoal, chalk, and ink; and many types of photography – and this represents merely a tiny fraction of all the various techniques and materials that one comes across.

Paper’s felt-like structure enables it to be a very strong material, even as it is flexible and absorbent.

Photo: Nasjonalmuseet / Anne Hansteen Jarr

The structure of the paper in combination with for example pastel, watercolour, pencil, or felt pen makes the conservation of art on paper an exciting job. When treating a paper-based work, the conservator must take into account its present condition as well as the technique that was used to create it. Of course, the quality of both the paper and the drawing medium play a significant role for the durability of the paper and the work of art.

Common damages to paper

Many of the damages that a paper conservator must remedy are caused by well-intended but ill-suited repairs – ordinary self-adhesive tape, for example, can cause a great deal of damage over time. People should always contact a conservator instead of carrying out repair work on their own, which may only make things worse.

In general, there are three main categories of damages to paper: mechanical, chemical, and biological.

  • Mechanical damages, such as tears, holes, folds, or dents, are often due to improper handling, incorrect mounting, or inadequate storage conditions.
  • Light is one of the prime culprits of chemical damage. Light, whether it is visible or invisible, can alter the paper so that it becomes brittle and yellowed. Pigments that are not colourfast can fade and potentially even vanish. The air that surrounds us contains gas that may bond with the material and gradually lead to decomposition, and the objects themselves may contain chemical substances that lead to decomposition.
  • Since paper is an organic material, inadequate storage conditions may cause it to succumb to biological damages in the form of mould or insects such as silverfish, borer beetles, or booklice.
A piece of art is loosened from its assemblage to be conserved.
Photo: Nasjonalmuseet / Anne Hansteen Jarr

Textile Conservation

The National Museum has an extensive collection of textiles that range in time from the early Middle Ages until today.

The collection consists mainly of Norwegian and European textiles and historical clothing, tapestries, textile furnishings, and modern decorative arts.

A textile in a museum collection is a source of history. It should be treated accordingly so that it lasts as long as possible and provides us with accurate historical information.

Textile as material

An eclectic textile collection, such as the one the National Museum possesses, features a wide variation in materials and techniques. Natural fibres such as wool, silk, cotton, and linen represent the main group of materials, but synthetic fibres such as viscose rayon, acetate, polyamide, polyester, and acryl are becoming ever more common. In the future we must be prepared for these more recent, “intelligent” materials.

A wide variety of techniques have been used throughout the ages, with woven textiles such as carpets, curtains, upholstery, and clothing textiles representing the largest portion of our collection. Other techniques that feature prominently include knitting, lacework, crochet, and embroidery. Textiles are often used in combination with other materials, such as hide, leather, wood, glass, rock, metal, paper, and plastic. This encourages a good deal of interdisciplinary cooperation with our colleagues from the other material groups.

Photo: Nasjonalmuseet

Textile fibres age and decompose. Our task is to mitigate the external factors that have a corrosive effect on these materials. It is essential to control factors such as light, temperature, humidity, and air quality. 

Light is perhaps the single factor that has the potential to cause the greatest damage, gradually causing colours to fade and uncoloured textiles to yellow. These external changes are accompanied by a degradation of the fibre itself, thereby undermining the fabric. It is also imperative to control temperature and humidity, which should both be kept as stable as possible.

Too high values can stimulate the formation of mould and the growth of microorganisms, while too low values can dehydrate the fibres, which thereby becomes brittle and inelastic. Poor air quality caused by pollution leads to dust and dirt. Preventive conservation therefore begins with in-depth knowledge and the chemical and physical properties of the material. This enables us to create stable and secure conditions for both storage and exhibitions and to choose the proper materials.

Treatment of textile objects

Certain objects may require more extensive conservation. 

  • Before the conservation work itself begins, the object’s history, material composition, and physical condition are thoroughly examined and documented/photographed. 
  • Which form of treatment that is selected is determined by the extent of the damage, the condition of the material, and whether the object is to be displayed or stored.
  • All interventions and changes are documented in writing along with photographs taken before, during, and after conservation. In certain cases, it is necessary to make supplementary drawings. 
  • It is especially important to document changes, as we must be able to differentiate the original material from later additions that were made so the object could retain its value as a historical source.