We recently investigated how long exposures during digitization might be affected by different physical locations. We tested 4 locations and 2 shutter speeds to capture the blur induced by walking heavily around the copy stand during exposure.

The 4 areas tested were:

1. Concrete Foundation at the ARC
2. 7th floor of Alkek Library in the Corner of the Building
3. 7th floor of Alkek Library in the Center of the Building
4. 2nd floor of Alkek Library on a Raised Floor installed over carpet for data & power lines

We tested 2 shutter speeds that are representative of those we use to digitize film negatives using Artograph LightPad Pros:

1. 1/10th of a second
2. 1 second

The test negative is one of my 6×7 cm negatives containing an image I visually verified to be in-focus, sharp, and lacking blur from camera or subject movement using a loupe. The portrait of Samantha was shot with a Mamiya RB67 Professional S and 127mm lens on Fuji Acros 100 developed by hand in Pyrocat HD.

Samantha on the Balcony by Jeremy Moore

I chose the area around Samantha’s right eye as the point of comparison because of its sharpness and many fine features, such as eyelashes. The following are animated GIFs that flip back-and-forth between two images: an exposure made with someone walking heavily around the copy stand (denoted by ‘BLURRED’ in bright, red text) and an exposure without.

Concrete Foundation at the ARC – 1/10th second

Concrete Foundation at the ARC – 1 second

7th Floor of Alkek Library – Center of Building – 1/10th second

7th Floor of Alkek Library – Center of Building – 1 second

7th Floor of Alkek Library – Corner of Building – 1/10th second

7th Floor of Alkek Library – Corner of Building – 1 second

2nd floor of Alkek Library on a Raised Floor installed over carpet for data & power lines – 1/10th second

2nd floor of Alkek Library on a Raised Floor installed over carpet for data & power lines – 1 second

From these tests, we have come to the following Conclusions:

1. When tested under adverse conditions, blur is visible in long exposures on a concrete foundation (see Caveat 1 below)
2. There is a visible and significant difference in blur when comparing the Center to the Corner of the 7th floor
3. Raised floors are anathema to high-resolution photography!

Caveats:

1. The concrete foundation may have fared better if a sturdier table had been available at the ARC (we used a rolling table with locking casters, while all other tests were performed on a heavy, wooden table without wheels)
2. These tests were not performed on a windy or stormy day, which may greatly affect the results on the 7th floor
3. Testing took place on a Friday afternoon with few library patrons in the building; results in Alkek Library may vary during periods of high use and/or between classes when more people are moving in, out, and around the building

Jeremy Moore

jeremy.moore@txstate.edu