in the 
1. This 
3roups 
nother, 
er than 
his was 
rating. 
1 more 
lerlying 
o what 
"mposi- 
ment it 
people 
ing one 
ashing- 
he very 
have a 
we shall 
gures. I 
ed in it 
ther do 
sponses 
se slides 
al photo 
alt with 
. United 
o inter- 
erienced 
nderline 
y tactical 
es wide- 
confined 
en quite 
different 
llside as 
aircraft 
ire spent 
we have 
3 days of 
lys, with 
| 6 hours 
  
DISCUSSION ON PRESENTED PAPERS 121 
of interpretation per day. Of the earlier ones, the 
ones that related to strategic targets, these men 
were actually being paid to do this work, they 
were doing it in their own time, highly motivated, 
and they could take as long as they wanted. We 
have no indication that they were rushing. I 
think it took them about 4 hours per target. 
CHAIRMAN: With your permission, we will 
pass on to the next paper that has the benefit of 
discussion, Mr Olson’s “Aerial Photography at 
the University of Illinois”. 
Does anyone have any questions or desire any 
amplification on the points that Mr Olson has 
raised in this paper? 
Mr Orsow: This is probably, at least in the 
United States, a programme which has been 
most widely known. We found as we went ahead 
that with our work it was absolutely mandatory 
that we have our own aircraft camera and 
laboratory facilities. We found it was impossible 
to do two types of job with commercial photog- 
raphy. 
One was the type of photography that is re- 
quired when something unexpected arises and 
you want pictures “now”. It was found difficult 
to get a commercial firm to break off their 
commercial operations and fly some place else 
for fifty or sixty dollars’ worth of photography. 
They cannot afford to do this. We can do it very 
inexpensively because we have an aircraft that 
has had, over close to 10 years, a suitable air- 
craft on the ground maintained in flight-readi- 
ness to take off. 
The second problem that we have is getting 
aerial photographs under precise conditions. 
For example, one of our departments wanted 
us to have a photograph taken precisely at the 
moment when we have a field personnel in the 
field collecting full data. How can we ask a 
commercial firm to call us on the telephone 
they say, “we are going to fly today”; we say, 
“we cannot put our people into the field today, 
you had better fly to-morrow”. 
For these two basic reasons we put a camera 
on our plane. Once we started this we soon had 
a rapidly growing collection of aerial negatives. 
These have proved very valuable in our teach- 
ing progress, not only to us but to certain other 
schools who had drawn on and printed from 
these negatives. At this time we knew, as every- 
one else had known, a tremendous quantity of 
photography, some of it military, some of it 
commercial was being destroyed for lack of 
Storage facilities or lack of usefulness. Now this 
is the very photography that people do not want 
to destroy, and that could be very valuable in 
teaching activities. We have attempted to get 
a certain amount of this photography. In view 
of this, we have thought it was possibly the 
biggest service we could render. For this reason 
we established an air photo repository which 
could accept negatives from any depositor. We 
then hold these negatives subject to recall by 
the depositor. In other words, we have an open 
film library. The only restriction we put on this 
is one of physical limitation. We do not want to 
build the entire library with pictures of France 
or Engeland or Australia. We are trying to get 
a representative sample of many different coun- 
tries and various conditions. We would like to 
be able to build a repository of representative 
samples of almost any type of terrain, vegetation 
or land forms which an interpreter might have 
to interpret in any part of the world. We have 
had some success in accomplishing this, once 
we get the negatives within the repository. As 
long as we hold that negative we will make a 
print off this negative for anyone requesting 
that print. In other words, we will not accept 
classified or restricted negatives; if they are 
going to be reproduced for only certain people, 
we do not want any part in it because we cannot 
afford to keep a double bookkeeping system. 
Once the negative goes into the repository there 
is a standard price-list on which costs are deter- 
mined and anyone else can to some extent 
determine the charges that will be associated 
with these prints. At the present time these 
prints are 9 X 9, single weight, glossy finish, 
contact print. The initial price is 55 cents a 
piece, which is just about three and a half 
shillings, I believe. And as the print order from 
a single roll of film increases, there is admini- 
strative saving to let us reduce the price very 
drastically, but even this, while the costs are 
relatively low, has not been adequate to meet 
the need for many small pools. To go as low as 
possible is essential, $1.50 for each of maybe 
29 students in a class for a series of 40 different 
photographic examples is prohibitive in many 
cases. For this reason we have attempted to 
build a collection of prepared stereograms 
whereby we take each of the individual photos 
in stereo pairs and very rigorously re-orientate 
the base line and photo-copy this, so that an 
individual stereogram pair would appear to 
warrant 8 X 10 print. These are designed to 
illustrate a specific feature of geological form 
or some other form. These can be reproduced 
at less than the cost of one 9 X 9 print. They 
have the advantage that the distributor does not 
have to orientate them himself, which means