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Cleaning and perception of objects

Influence of objective and subjective aspects in decision-making about the cleaning of objects.

The aim of the project was to help conservators determine whether a cleaning method is 'safe' for specific object types and materials, such as acrylic paint, daguerreotypes, face-mounted and laminated photographs and silver.

Daguerreotype NFM

Daguerrotype of the Netherlands Photo Museum (NFM)

The project was carried out both on 'objective' results of technical studies, and on the 'subjective' observation and perception of the conservator, the scientist and the viewer.


A recurring question with the conservation of objects is the effect of the cleaning process (or the treatment process in general) on the appearance and the possible changes in perception and readability.

Objective and subjective approach

The perception of an object depends on chemical and physical properties. On the one hand there is the surface (colour, roughness/texture, shine, effect of transparent layers, craquelure, influence of lighting, etc.), i.e., the objective approach. On the other hand there is the context in which the object was created, is exhibited and viewed (perception, visibility of a particular change, how the change affects the readability of the object, etc.), i.e., the subjective approach.


For the correct choice of a cleaning method for a particular object, it is important that both the objective and the subjective approach are considered in the decision-making. On the basis of this and other information it can then be decided how a conservator could treat an object and whether the object may/can/should be treated at all.

Socratic dialogue

To answer these questions and make decisions it is necessary that one is aware of the objective and subjective aspects. A number of case studies were carried out to demonstrate this approach and, at the same time, arrive at concrete results that conservators can utilise. Hereby the Socratic dialogue was put to use. This involves creating a 'safe' environment for participants to discuss and explore the various aspects of conservation decisions and ethics.

Case Studies

This project involved case studies from the projects below: