Each photo in this collection was taken with a photo-recording transit designed by W.B. Osborne, the Regional Forest Inspector during the project, and custom built by Leupold - Volpel & Company of Portland Oregon. The camera rotated as each photo was taken minimizing lens distortion across the photo. The photos were recorded on 14 -1/4" by 5 - 1/2" negatives, three sets of contact prints were made for each photo. Along the top edge of the photo the azimuth (compass bearing) was recorded directly onto the film. Vertical angles measurement was recorded along the left and right edges of the print. Also, recorded were the date, location and elevation of each photo. Three standard photo setups taken at each lookout: the north view (60 and 180 degrees) taken around noon, the south-east view (60 to 180 degrees) taken around 3:00 PM, the South-west view (180 to 300 degrees) taken around 9:00 AM. Many of the photos taken during and after 1934 used infrared sensitive film which reduced the effects of atmospheric haze on the images. The foliage of trees in infrared photos appear very bright because plants strongly reflect infrared light.
