Monthly Archives: January 2017

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.

 

References

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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New Year’s Resolutions: Public Outreach

Exhibits are an important part of sharing information with the public and making historical items accessible. They also provide an opportunity to educate visitors on specific topics and showcase items of importance to the community. Public outreach events are another way to involve the public with the archives. Below are a few public outreach event examples to inspire your archives to offer events this year; some of the events below have been offered by Albertan institutions in the past with success.

  1. Create a Time Capsule

Involve community members by encouraging them to donate a small item, such as a photo or letter, for a time capsule project. The time capsule can be put into the vault to be used in the future for an exhibit. This project could take place over a particular holiday, which would provide content for an exhibit for a future holiday.

  1. Rehouse Prized Collections

A 2-3 hour hands-on workshop on proper housing and handling techniques can be taught to comic book and sports card collectors. Archival grade folders, binders, encapsulation materials, and labels can be sold as part of the workshop kit.

  1. Make a Portfolio or Window Mat Folder

A hands-on half-day workshop can be hosted where registrants have an opportunity to create a portfolio or a window mat folder to house an art print. A supply kit for the workshop could be sold upon registration. This workshop would appeal to artisans, art collectors, or art students.

  1. Make Long Lasting Memories

A presentation on choosing papers and glues to safely display photographs and memorabilia can be offered to the scrapbooking community. An additional workshop could be offered to the calligraphic community on choosing lightfast inks and watercolour paints. It is recommended to have samples available to show registrants.

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