The basic idea
Some objects are fragile. Paper, textiles, photographs, watercolors and certain dyes can fade or weaken with light. Others can be damaged by touch, vibration or changes in temperature and humidity. Every time an original is moved, mounted or displayed, there is some risk.
A digital surrogate is a high-quality digital copy of an object or document: a photograph, a scan, a 3D model or a recording. Showing the surrogate in a gallery lets the original spend more time in storage, where conditions can be controlled. The surrogate is not the object, but it can stand in for some uses.
How surrogates help
Less light exposure. Light-sensitive materials are typically displayed under low light and for limited periods. A digital version can be shown for as long as the museum wishes without adding to the original’s exposure. A screen cannot deliver the experience of seeing the real thing, but it can offer a way to look at details when the original is resting.
Less handling. Researchers and curious visitors often want to turn pages or look at a back or underside. Zoomable images, page-turning views and rotating 3D models can answer many such requests without anyone touching the item. This is useful for books, albums and delicate three-dimensional objects.
Access to what cannot be displayed. Some items are too fragile to exhibit at all, or are rarely shown because space is limited. A screen or an online collection can still let people study them.
Support for loans and travel. A digital version can be shown locally while the original is out on loan or being treated by a conservator. For touring exhibits, a surrogate may sometimes travel in place of an object that is too risky to move, though lenders and insurers often have their own requirements.
A record of condition. Careful imaging at a point in time documents how an object looked then. Conservators sometimes compare images over years to notice change. This is helpful but is not a substitute for professional condition reporting.
Methods
Different objects call for different techniques:
- Photography. Good object photography with even lighting, a neutral background and a scale reference suits many items. It is often the most accessible starting point.
- Flat scanning. Documents, maps and photographs are often captured with scanners or overhead camera setups that support the item without pressure. Method choice depends on how fragile the material is.
- 3D scanning. Techniques such as photogrammetry or structured light can record shape and surface. Results depend on the object’s material; shiny, transparent or very dark items can be difficult. 3D scanning is covered in its own article.
- Audio and video. Recordings of fragile media or performances can preserve content that would be risky to play on old equipment.
Capture quality matters. It is usually better to capture at a higher quality than you currently need and derive smaller versions for display, rather than the reverse. Questions of image resolution and file formats should be settled early, since recapturing an original means handling it again.
What a surrogate cannot do
A copy cannot reproduce scale, texture, smell, weight or the feeling of being near the real thing. For many visitors, those qualities are why they come. Some details, such as the exact color of a pigment, are also hard to reproduce faithfully on different screens. A surrogate should therefore be described honestly as a copy, not as equivalent to the original.
Digitization also is not a reason to neglect the physical object. Originals still need suitable storage, monitoring and care. Handling during the imaging process is itself a risk, and a conservator should usually advise on whether an item is stable enough to be imaged.
Information that makes a copy useful
An image with no description is of limited use. Good collection metadata records what the object is, where it came from, when and how it was captured, and what rights apply. Without it, the file may become impossible to interpret years later. Rights also need checking before anything is displayed or shared online, including image permissions and the status of any orphan works.
Some communities have views on how cultural material should be shown, copied or shared. Digitizing is not always appropriate, and consultation with source communities is a good practice before publication.
Starting out sensibly
Small institutions can approach this in stages:
- Identify the objects most at risk or most often requested.
- Ask a conservator or experienced colleague whether each is suitable for imaging.
- Capture a small, well-documented set at good quality.
- Store master files with backups in more than one place.
- Create display versions for exhibits and, where appropriate, for the web.
These steps need planning, time and storage, and costs vary widely. A modest, careful project is typically more valuable than a rushed large one.