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.
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|
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.|