EXPOSURE OF PHOTOGRAPHIC MATERIAL WITH LASERS

• Document Type: CREST
• Collection: NGA Records (Formerly NIMA)
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78B04770A002600010009-5
• Release Decision: RIPPUB
• Original Classification: S
• Document Page Count: 6
• Document Creation Date: December 28, 2016
• Document Release Date: December 5, 2002
• Sequence Number: 9
• Publication Date: September 8, 1964
• Content Type: REQ

Approved Forease 2003/01/28 : CIA-RDP78B0477AQ02600010009-5
SECRET
25X1
PAR 216
8 Sept 64
SUBJECT: Exposure of Photographic Material with Lasers
TASK/PROBLEM
1. Determine the manner and degree of the interaction of present and
predictable future photographic films with coherent radiation from laser
sources in red and near IR spectrum ranges.
2. During this quarter, two specific areas of laser and photographic 25X1
film interaction were investigated. The first was a refinement of the study
of the effect of 6328A laser illumination on the gamma value of panchr
film- he second was an investigation of reticle projection using the
Helve gas laser.
3. Gamma Investigation:
a. In the last quarterly report, we described an apparent difference
in the gamma of Type 8401 Plus X Aerecon film with 6328A laser exposure and
equivalent filtered tungsten light exposure. This was a surprising result;
therefore, a more refined experiment was designed to recheck the re-sults.
b. In the new experiment, one piece of film was exposed with the
Model 101 Sensitometer (filtered tungsten light) and a second piece with the
divergent laser beam through a calibrated step tablet placed directly in front
of the film plane. By developing both pieces of film together and measuring
their densities with the 31-A densitometer, their gamma values were compared.
The results of these measurements are tabulated on the following page.
SECRET
Declass Review by
NIMA/DOD
-23-
Approved For Release 2003/01/28 : CIA-RDP78B04770A002600010009-5
 Approved ForpAwease 2003/0 ECRETDP78B0477QA 02600010009-5
PAR 216
25X1
8 Sept 64
Exposure Source
101 Sensitometer
Laser
01 Plus X Aerecon
Developed in D-19
8401 Plus X
Developed
Aerec
in D-7
on
6
Series
Series
Series
Series
Series Series
Series
Series
1
2
3
4
5
6
7
8
1.12
1.17
1.06
1.02
.99
1.00
.76
.92
1.12
1.04
1.10
1.04
.98
1.07
.89
.88
c. Considerable variability in the gamma values obtained for laser
exposure was caused by lack of laser beam uniformity. Within the experimental
error of this experiment, it was concluded that no difference exists in the
gamma obtained with laser exposure versus that obtained with a non-coherent
source of.the same approximate wavelength.
d. In the various experiments carried out on this project, we can
find no evidence that the photographic emulsion (acting as a receiver) reacts
any differently to coherent radiation than to non-coherent light about the
same wavelength.
e. Discussion of the nature of coherence with our
consultant optical physicist, and of the probable effect of coherence upon
latent image formation with
1 1, has provided theoretical confirmation of that
observation.
SECRET
-24-
25X1
25X1
Approved For Release 2003/01/28 : CIA-RDP78BO477OA002600010009-5
 Approved For ease 2003/01/28 :'0B0477 A(02600010009-5
PAR 216
8 Sept 64
f. The interference effects observed in photographic exposures to
laser (or other coherent radiation) can be explained as interference occurring
outside the receiving photographic emulsion.
4. Reticle Projection Investigation:
a. In preparation for studies of the behaviour of photographic
materials as the object in optical projection with a laser source, a pre-
liminary reticle projection study was initiated to compare tungsten versus
laser sources in an optical projection system.
(1) The laboratory set-up for this study consisted essentially
of a single element lens which projected the .005-inch and 0.1 millimeter
scales of al measuring magnifier onto a 4 x 5 inch sheet of
SO-243 film. Exposures were made by positioning the film plane at the geo-
metrical focus of the projection lens and at several positions both ahead of
and behind it.
(2) The initial results of this study are shown in Figures 1
through 9. Figure 1 shows the reticle image at the geometrical focus of the
projection lens illuminated with a tungsten lamp. Figure 2 is the same as
Figure 1 except that the reticle was illuminated with the laser beam. This
second print is comparable in image quality; however, the familiar interference
ring patterns are still present. Figure 3 is obtained in the same manner as
Figure 2 except that the laser beam was diffused by a ground glass surface.
In this print, the image quality is greatly reduced and the ground surface
does not appreciably improve the beam uniformity.
(3) Figures 4, 5, and 6 show the reticle image at 3 positions,
all beyond the geometrical focus, each illuminated with the tungsten filament
source. Figure 4 w4s exposed with the film plane 3mm beyond the focus; Figure
5, 12mm beyond the. focus; and Figure 6, 45mm beyond the focus. This defocussing
simply caused a smearing of the image in proportion to the degree of defocussing.
SECRET
-25-
Approved For Release 2003/01/28 : CIA-RDP78B04770A002600010009-5
 Approved For Release 2003/01/2 78B04770A002600010009 :,Ili
6, 6)1
Figure 1. Reticle image at
geometrical focus of lens
with tun{-;:,ten illumination.
F gure " , Reticle image at
geometrical focus of lens
with laser beam diffused by
a ground glass surface.
b&GRET
Figure : . Reticle rr:age at
geometr ,al- focus f len:'
with 1 ~ (- 7llumi i ion.
Figure Reticle image w Al
f'.*L-Lrn ' rnr , 1)cyand gc metric i 1
focus w r,h iungstc i1lcrn
:na: t ion
s1u '! -i
Cxc d d irarn arrto .dick
n r ,inP ~7d
Approved For Release 2003/01/28 : CI$6RDP78B04770A00260001000 ?~~
 Approved For Release 200 j 1/28: CIA-RDP78B04770A0026006%806O5
8 Sept ()1
t'igure 5. Reticle image with
film 12mm beyond geometrical
Focus with tungsten illumi_--
na.tion.
Figure f). Retic- e image w: t h
f'ii_m+5ram beYonc ,;eometri( .l
Focr~.s w~_th tunfr. ten ilium. -
natirn::,
Figure-'(. Reticle image with
Pi-lm 3mm beyond geometrical..
POCSS with laser ii_llunina.tion..
la i gure 8. Reticle image with Fi glare 1). Reticl n image w- t h
.2. w_ .. .
f,i In 1'~mm beynn a ,?cometrica] film ~ 57rim beyonw creometri.c =j L r"""c
GRLT
Approved d l ~s~'2003/0 8: CIA-RbP78BO4t 'OA002600dt?Do8-5 i o ,
 Approved For Wase 2003/0d ftf% ffDP78B04770002600010009-5
8 Sept 64
(4) Figures 7, 8, and 9 show the same projections as 4, 5, and
6 except that each was illuminated with the laser beam. In these three prints,
a constructive interference pattern of the regularly spaced lines can easily
be.observed. Figure 7, for example, shows the diffraction pattern as it be-
gins to form; a pattern that cannot be detected in print 4. Figure 8 begins
to show reinforcement in both the line patterns and the numerals as contrasted
to the soft blur of Figure 5. Figure 9 clearly shows the regular reinforced
line patterns and this is essentially nonexistent in Figure 6.
b. To continue this study, a high quality projection system is re-
quired in order to obtain a quantitative evaluation of these interference
characteristics. Currently, such a system is being designed and built. This
system will be diffraction limited and capable of measuring spatial frequencies
in excess of 100 lines per mm. In addition, the system will have provisions
for evaluating the effect of aperture size and shape on the modulation transfer
function.
AW lav~ PLANNED ACTIVITY
5. The question regarding the behaviour of sensitized materials as a
receiver for laser radiation has been answered and this phase of the project
should be closed and reported.
6. The consideration of film as the object in a projection system with
a coherent source includes a multitude of variables, such as phase shift by
the developed image, effect of index matching immersion, spatial filtering
effects, etc. This phase of the project should be carefully discussed with
the customer to outline a program which will not overlap other activities in
progress.
7. The high quality projection system is awaiting delivery of one over-
due item to be set up in a dark room ready for use.
SEGRET
Approved For Release 2003/01/28 : CIA-RDP78BO477OA002600010009-5
.W