resolving 
f the fre- 
1 positive 
luce cor- 
you have 
ng power 
ive emul- 
we — and 
rials are 
they can 
evidence 
aterial all 
valuated. 
» the con- 
disagree- 
| not used 
d the best 
available 
but I did 
parencies 
y, to state 
t can be 
y. How- 
'emark: it 
)out reso- 
nfuse dis- 
contrast 
s thing. I 
future if 
just mean 
‘we want 
erests the 
the pho- 
f size of 
llimetre — 
more as 
|; be judg- 
insmission 
I know 
>d on this 
he audito- 
s paper - 
- was that 
iterion but 
g positive 
n, this cri- 
ild not be 
insmission 
-O-Wat is 
it. We also 
mission of 
to the con- 
  
  
  
clusion that the spot size or the unsharpness of 
size in the Kel-O-Wat is much smaller than in 
the other printers. On the other hand, in normal 
cases using normal photographic material the 
feed-back is much less due to the defective 
transparency to infra red of these materials, 
particularly of positive paper. I can give you a 
few figures on this point if you like. 
Mr J. SrREET: Speaking on the subject of 
colour printing and colour enlarging, I would 
like to say that we are continuing our work in 
America. We have such working enlarging 
equipment for colour negatives in operation now 
in customers' plants in America. There is some 
experimental colour contact printing equipment 
in operation and we have not overlooked this 
coming technique in photogrammetry. 
Mr F. L. CoRTEN: May I put a question to 
the last speaker on logetronics? Is there any 
chance of getting very much smaller scanning 
spots? Because what dodging printers now do 
is to improve macro detail (larger sizes) and 
these sizes are of the order of about 1 inch; 
there is a range between the large size detail 
improvement and the very small size improve- 
ment which is not convered by the scanning 
spot printers. That is to say, the reproduction 
of, for example, a very small house or a power 
Archives 4 
PROGRES ACCOMPLIS, DISCUSSION 
line, maybe a road, which is smaller than the 
spot size is not improved by the scanning spot 
printers. It is only improved by being able to 
use a more contrasty positive material; that is of 
secondary importance, it is important but not 
essential. It would be an essential improvement 
if these positive instruments could be adapted 
to the image size and the detail size which we 
have. I know that there are various difficulties, 
but I would like to ask if there is any possi- 
bility in the future for the’ electronic scanning 
spot printers to do this? I know that it is in the 
fluorododge principle that it is basically possi- 
ble to do so. 
Mr J. STREET: Yes, Sir, I would say defi- 
nitely, especially with the improvements in the 
phosphors for cathode-ray tubes and the use of 
transparent phosphors which removes the grain 
to a very large extent. The development of 
higher resolution electron guns in the tubes, the 
production of small spots, is becoming more 
and more practical. However, there is always 
the difficulty that printing times are rather slow 
in this equipment when you have very small 
spots you also in general are limited in light, 
so there is a problem of printing speed. We re- 
cognise the difficulty, but many of the develop- 
ments in the cathode ray tube industry, in par- 
ticular, will help us in the future.