THE NEED FOR AN INTER 
23.7 ea Dee 
: = 
NATIONAL TEST HOUSE FOR AIR FILMS 
rares N 
I= 
   
J. A, EDEN 
a 
Précis 
There is a lack of dependable information with regard to the 
comparative character istics of different available „ir films so that 
many users employ films which are not the nost suitable for their 
work, thus losing a large amount of the information they might 
otherwise obtain. 
It is considered that there is an urgent need for an Interna- 
tional Test House continually to test all films thought to be usable 
and to publish their test results. This would act as an incentive 
to emulsion manufacturers, and supply urgently needed information. 
CSSS EE NES TEE NES NOTE SE 
  
DESSOUS RSR NOTE OS FERN SAN EE N EL TE 
Economy and accuracy in Photogrammetry today depends more than 
anything else on the resolution and sharpness that can be captured. 
This is a function of the whole photographic process including the 
weather, the en e the camera, the exposure, the film and the 
processing. Today an important limiting factor tends to be the 
film. 
   
It is clear that the characteristics of the film used are 
extremely Saban In spite of this, although much attention is 
given by our industry to the choice and use of cameras, a quite 
insufficient amount of attention is given to films and their proper 
use and development. Users tend to restrict their choice of films 
to types with which they have had previous experience and only to 
change to more suitable types most reluctantly for lack of dependable 
information, In this way the potentialities of improved camera 
optics are frequently not realised. 
To correct this there is a need for the comparative testing of 
different films available on the market. This is something that 
cannot easily be undertaken by the individual user, as he is 
concerned not only with the resolution of the film, but also with 
its other properties such as its speed, its contrast, its sharpness 
its tes s qualities; the consistency in the performance of 
different batche8, its dimensional stability, its tendenoy to 
produce Stabi markings and other factors. These gualities need to 
be comparatively determined and assessed in relation to the perform- 
ànce of the camera it is proposed to use, and there are now so many 
produets av: ailable that the amount of work involved in the testing 
bended to stress the need for an international 
to test films by suitable standard methods and 
| is | of tests so that the products of different 
film manufacturers could be most usefully compared, 
mh 3 \a TED 
inis pape 
  
Such house could provide two very valuable services. 
First it enable users in our survey industry to choose the most 
DITS lU enao. Jy ; 
suitable 0 effect the largest economies in their work either 
  
' obtaining greater accuracies. Second, it would 
provide an to manufacturers to produce better films more 
quickly because the result of such tests would be to eliminate the