BRIEFING PRINT ENLARGER

• Document Type: CREST
• Collection: NGA Records (Formerly NIMA)
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78B04770A000500010017-9
• Release Decision: RIPPUB
• Original Classification: K
• Document Page Count: 6
• Document Creation Date: December 28, 2016
• Document Release Date: October 8, 2004
• Sequence Number: 17
• Publication Date: March 5, 1964
• Content Type: REQ

Approved For R e se 2004/11/30: CIA-RDP78B04770A5C
BRIEFING PRINT ENLARGER
5 March 1964
NGA Review Complete
TRACT FILE
PAR 202-A
Approved For Release 2004/11/30 : CIA-RDP78BO477OA000500010017-9
 Approved Forlease 2004/11/30: CIA-RDP78BO477 00500010017-9
5 Mar 64
SUBJECT: Briefing Print Enlarger
TASK/PROBLEM
1. To design and fabricate a prototype enlarger for exposing
high-quality briefing prints in format sizes up to and including 20" x 24".
Magnification to be in the 10 to 60 diameter range. The enlarger is to have
the capability of producing both black-and-white and color prints. Change
from one capability to the other should be made with a minimum amount of
effort.
2. It is proposed that approval be granted to conduct design
studies through use of breadboard test equipments and then design and fabri-
cation of one (1) prototype briefing print enlarger. Design studies will
explore problems associated with the critical parts or assemblies of the
end item as follows :
a. Objective Lens and Condenser Lens Design:
(1) Lens design studies will be conducted to provide
two families (black-and-white and color) of objective lenses and their mating
condenser systems. Each family of objective lenses will provide for the
desired print size and the full magnification range. Each lens in the family
group will cover only a limited portion of the whole magnification range
(10 - 60X) consistent with good image quality, i.e., one lens may cover
10 to 20X and the next 15 to 25X, etc.
(2) One family of lenses will be corrected for a nar-
row range in the blue-green region of the spectrum for maximum image qualit
on non-color-sensitized print materials (Kodabromide or Resisto Rapid types.
The second family of lenses will be corrected for the full visible spectrum
for use in exposing color print materials or variable contrast papers. Field
flattener elements will be employed in the design in both the lenses for
black and white and the lenses for color.
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5 Max 6!t
b. Enlarger Arrangement: To cover the 20" x 24" format
at all magnifications within the field angle-limitation of high-quality
objective lenses, considerable optical path length (up to about 7 feet)
will be required. Because of this, the operator can only have convenient
access to both the negative and print stock through a folded or horizontal
optical path. It now appears that the horizontal arrangement may lend
itself to better optical quality and simpler mechanisms. However, a var-
iety of folded arrangements will be considered before final. commitment to
a specific arrangement is made.
c. Lens Focus Control:- For the proposed high-quality variable
magnification enlarger, a system for precise resetting of the precalibrated
focus for each magnification value must be provided. Present opinion is that
the "tensioned thread" lens focus mechanism, as used in the 10 - 20 - tiOX
precision enlarger, combined with a lead screw drive for the print easel
should be considered. Servo systems vs manual control of the settings from
a tabulation of magnification, easel position, and lens position will also
be reviewed with the most suitable solution employed.
d. Illumination : System: The design of the condenser lens
and/or lenses will be considered with each objective lens design to deter-
mine that the proposed field size and desireable lens aperture sizes are
compatible with available light sources. It is proposed to use projection-
type tungsten lamps as the source(s). Color filtering and heat filtration
will be provided in the illumination system design. The lamphouse assembly
will be removable to permit gate cleaning and easy replacement for color
printing. A mechanism for clamping the negative against the registration
glass and releasing the negative for transport or removal will be incorpor-
ated in the film gate design.
e. Print Stock Easel Design: The print stock holder will
provide for a 20 x 2LG" exposure format area. Provisions will be made for
protection of the print stock from exposure while measuring exposure level.
Protection will be such that the raw stock is also protected under subdued
white light conditions for loading and removal of negative rolls, minor
adjustments, etc.
f. Exposure Monitoring and Control: A system to accomplish
exposure control and monitoring must:
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 Approved For.ease 2004/11/30: CIA-RDP78BO477 00500010017-9
PAR 202-A
5 Mar 6L
TAT
a. Roll paper supply of 250 feet length vs 100 feet length.
b. Rotation of the easel to orient print image.
c. Daylight loading magazines compatible with processors, etc.
Design objectives for the enlarger are:
(1) Measure the required print exposure (a commercial
photoelectric easel photometer EP-1000) will be employed).
(2) Control the exposure by adjustment of the lamp volt-
age and/or exposure time.
printing lamp.
(3) Start and end the exposure by turning on and off the
g. Vibration Control: Through previous experience, good free-
dom from vibration effects has been achieved by building the optical unit as a
single rigid system which in turn is isolated from the remainder of the machine
and the building by very soft vibration isolation mounts, The design study
will investigate rigidity and the mounting of the critical assemblies to the
main structure in a manner to insure vibration-free photography.
3. Special consideration will be given to:
a. High-image quality.
b. Reliability.
c. Maintainability.
4. The following items will be investigated to determine degree
of effect, if any, on the items listed in par 3 above:
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PAR 202-A
5 Mar 6L
. a. Magnification range: Magnification range will be
10 - 60X with the ability to obtain desired magnification within the range
through lens selection and pre-set focus.
b. Print size: To be 20 x 2L" on roll paper.
c. Negative handling: Provide for roll film, 70mm to 92"
wide and lengths up to 500 feet on MIL. Standard spools.
d. Printing capability; The primary optical system to be
designed for maximum image quality on color-blind print stock. The second
optical system (interchangeable with the primary one) will permit exposure
of color materials or variable contrast black-and-white print stock.
e. Film Gate: A. fluid injection negative gate with air stream
fluid removal will be employed. In addition a means will be provided to quickly
present to the printing gate from frame and X-Y coordinate identification the
negative area to be printed. It will be possible to place any point within
the negative area at the optical axis of the lens.
f. Provide an exposure monitoring photometer.
g. Exterior design: To be smooth to facilitate cleaning as
required for proper housekeeping in film handling areas.
h. Insure high efficiency, simple construction and low main-
tenance requirements.
6. To design, fabricate, test"and deliver one each high-quality
briefing print enlarger. Effort to be scheduled in two phases:
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PAR 202-A
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5 Mar 64
a. Phase I - Provide preliminary design, final specifi-
cation and optical designs. To reach these goals will require construction
of breadboards and/or models for testing of certain subassembly designs, ie.,
(1) Objective lenses and condenser systems for both
narrow spectral band black-and-white prints and full visible spectrum for
color reproduction.
(2) Print stock holder.
(3) Vertical fluid injection negative gate.
(4) Negative transport system with X-Y coordinate measur-
ing and frame counting. Test and-evaluation of items (3) and (4) of Par 6a.
above will be accomplished jointly with the similar effort of PAR 224, 3 - 15X
Fluid Gate Enlarger.
b. Phase II Gcmmplete the design, fabricate and accomplish
in-house testing of the prptotype enlarger.
7. Upon completion of Phase II, the enlarger will be crated and
made ready for shipment pending sped>al instructions from the customer.
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