(This paper was originally published in the proceedings of the 1976 ufo conference of the center for ufo studies. This version has been modified slightly in april 2000 for this Publication. This is the first of two technical and historical papers on The trent photo case that were presented to and published by The center for ufo studies (cufos), which is located in Chicago, Illinois. On the possibility that the McMinnville photos show a distant unidentified object (UO)

During the Air Force funded investigation of UFO reports at the University of Colorado in 1967-1968 (the "Condon Report"), photoanalyst William Hartmann studied in detail photographic and verbal evidence presented by two former residents of McMinnville, Oregon, Paul and Evelyn Trent. He concluded, mainly on the basis of a simplified photometric analysis, that "all factors investigated, geometrical, psychological and physical, appear to be consistent with the assertion that an extraordinary flying object, silvery, metallic, disk shaped, tens of meters in diameter and evidently artificial, flew within sight of two witnesses." An important part of his analysis included calculations of the expected brightness of the image of the bottom of the Unidentified Object (UO) that appears in the first photo. He pointed out that the elliptical image of the bottom was brighter than expected if the object were close and therefore a small model. The excessive image brightness led him to conclude that the object was at a great distance (over a kilometer), His conclusion was criticized by Philip J. Klass and Rober Sheaffer who argued that veiling glare (caused by surface dirt and imperfections in the lens which scatter light from bright areas of the image into all other areas of the image) could have increased the brightness of the image of the UO, making it appear distant.

This investigation revisited and improved upon Hartmann's method with the following modifications:

• the bottom of the UO in the first photo has been assumed to be as intrinsically bright as possible without being a source of light (i.e., assumed to be white)
• laboratory measurements have been used to estimate the magnitudes of veiling glare added to the various images of interest
• a film exposure curve has been used to determine relative image illuminances, and
• a surface brightness ratio, determined by field measurements, has been included.

The results of the new photometric analysis suggest that the bottom of the UO is too bright for it to have been a non-self-luminous white (paper) surface of a nearby object. Hence it could have been distant.

Introduction

In June 1950, four weeks after they were taken, the photos illustrated below appeared in the local newspaper in McMinnville, Oregon.

Subsequently, they appeared in Life Magazine and in many publications,devoted to UFO reports. Although they clearly depict an unusual object, they were never treated as scientifically valuable because it was always considered probable that they were photos of a hoax object (e.g., "a garbage can lid"). Nevertheless they did gain a large measure of scientific "stature" when, in 1968, Hartmann(1) concluded that the object may have been distant and, therefore, large (i.e. not a hoax). Since the publication of Hartmann's conclusion in the "Condon Report" (1) these photos and the verbal evidence associated with them have been the subject of a continuing controversy. A brief history of the analysis of the photos is given in Figure 3 (click to view).

A Brief History of the McMinnville Photos

Publication: 8 June 1950. The Editor stated that "expert photographers declared there has been no tampering with the negatives. (The) original photos were developed by a local firm. After careful consideration, there appears to be no possibility of hoax or hallucination connected with the pictures. Therefore, the Telephone-Register believes them authentic." - The Telephone Register, McMinnville, Oregon

Subsequent Immediate Publications:

• The Portland Oregonian, Portland, Oregon, 10 June 1950  (contains further verbal information)
• The Los Angeles Examiner, Los Angeles, California, 11 June 1950  (contains further verbal information)
• Life, June 1950  (contains further verbal information)

• There are some possible inconsistencies in the verbal evidence and several important discrepancies between the verbal report and the photographic evidence.
• Hartmann's photometric analysis was incomplete. Specifically:
  • [a] shadows on the garage wall (facing east) suggest that the pictures were taken in the morning, not in the evening as claimed;
  • [b] the apparent shrinkage of the shadow nearest the edge of the garage suggests that there were many minutes between photo 1 and photo 2; and
  • [c] veiling glare could have made the image of the bottom of the UO excessively bright thus leading Hartmann to erroneously conclude that the object was distant.