Our aerial photography is scanned at 600 ppi unless a higher resolution is requested. We have found that higher resolution scans rarely provide more detail. View the examples below to determine the resolution needed for your research.

File Size

The below table shows the approximate file size of 9 x 9-inch scanned air photos at various resolutions.

Resolution File Size (Black & White) File Size (Color)
 600 ppi 30 MB  100 MB
1200 ppi 100 MB  400 MB
2400 ppi 500 MB 1500 MB

Resolution Examples

Shown below are detailed portions of an air photo from flight AXM-1938A of Riverside County scanned at 600, 1200, and 2400 ppi. Click on the thumbnails to view the full resolution images.

 Frame AXM-39-67, May 30, 1938.
Full Image AXM-1938A, Frame 39-67 Detail scanned at 600 ppi
 Detail scanned at 1200 ppi  

Detail scanned at 2400 ppi

 

Finding Aerial Photographs
More about our Aerial Photography Collections