Tag Archives: Museums

Reflectance Transformation Imaging

Conservators, archaeologists, and conservation scientists use many pieces of equipment and methods of investigation to perform analysis of records, artifacts, and historical buildings. Analysis is performed to research materials, collect historical information, and determine how they can be preserved.

Outdoor sculptures, historic buildings, and even gravestones are severely affected over time due to the harsh environmental conditions that they must withstand. In order to work towards the preservation and documentation of these historical resources, researchers sometimes collect data on their surface, shape, and colour using Reflectance Transformation Imaging (RTI), also called Polynomial Texture Mapping. This type of analysis uses a computational photographic method that collects information on the surface through the use of light and camera positioning. It has proved particularly beneficial when decoding worn gravestones, friezes, hieroglyphics, and even faded manuscripts.

How does it work?

  • Multiple photos are taken of an object with a stationary camera, under various angles of light. The angles of light are knowns, and are required to collect the necessary images that will be used to create the final image.
  • Data produced by each image is interpreted by the RTI viewing software, then a mathematical model of the surface is created, which allows users of the software to manipulate an illumination feature to view the surface under various light angles.

 A similar method of photographic capture that is used for RTI can also be used for 3-D scanning. 3-D scanning is a popular method of collecting data of an object prior to creating reproductions or creating a digital manifestation.



Cultural Heritage Imaging. Reflectance Transformation Imaging (RTI). Retrieved from http://culturalheritageimaging.org/Technologies/RTI/.

Smithsonian Museum Conservation Institute. Reflectance Transformation Imaging (RTI). Retrieved from http://si.edu/MCIImagingStudio/RTI.

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Risk-Based Business


Credit: m. Photo has been cropped.

What is a risk assessment?

A risk assessment is an assessment performed of a facility, site, or collection to identify potential risks; the likelihood of occurrence; the damage if the risk occurs; and the cost, effort, and work to remediate those damages.

Why is it beneficial for archives to perform a risk assessment?

It is important for an institution to know their weaknesses in order to address them. It is also useful to know what the weaknesses are to determine what insurance coverage should be purchased. For example, it may be useful to purchase flood insurance if the collection is stored on a lower level.

If the institution has additional funding available to create a new job position, performing a risk assessment may assist with the decision of what position should be created. For example, if theft and vandalism are frequent occurrences it may be useful to have a security staff member on site.

If an institution is in the process of applying for grants, performing a risk assessment may assist with creating the grant application and knowing where grant assistance would be most beneficial. If awarded the grant, should the funding go towards remediating one large risk or a few smaller risks? This is called risk-based decision making; answering questions about potential risks and the outcome if risks are not addressed.

How is a risk assessment performed?

The Canadian Conservation Institute offers a service for which institutions can apply where a CCI conservation professional visits the institution to perform a facility assessment. http://canada.pch.gc.ca/eng/1449251671657

It is also encouraged for institution staff to set aside time once or twice a year to discuss what risks are present due to the type of collection material and media housed, the facility structure, security and access, electric work, plumbing, among others. It is important for facilities maintenance staff, cleaning staff, archivists, conservators, and collection technicians to work together as they may recognize different potential risks.

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