REPORT ON OPTICAL AND FLUID GATE PROBLEMS WITH THE (Sanitized)BRIEFING PRINT ENLARGER

• Document Type: CREST
• Collection: NGA Records (Formerly NIMA)
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78B04770A000500010035-9
• Release Decision: RIPPUB
• Original Classification: K
• Document Page Count: 4
• Document Creation Date: December 28, 2016
• Document Release Date: October 8, 2004
• Sequence Number: 35
• Publication Date: August 1, 1967
• Content Type: MF

Approved Fqr Release 2'004111/?0.:-CJA=RDP78B0#t7.70
NPYC/TD8/E-45/67
1 August 1967. ;
-M OI?P"UM FOR;: bepttty Assistant for Technical Development
Report on ti cal and Fluid Naito Problems
'with the is i`is,g Print nl anger
A. $ }
Since receiving'your dirac?tive on 2J4 July to invdatigate the dust
sand fluid gate problems on the Briefing Print Fal.s`urgar,, the undersigned
has completed three days of experimenta1 tests. The following conclu-
sion ,have been reached:
1) Three design 'changes are considered necessary. (a) The
mounting mans for one of the negative gate glass plates must be
changed to permit servicing it.., (b) Two metal. plates of the
vapor shielding must be altered in shape for better access, and.
(c) the lazsrphouse positioning hand crank must be replaced with a
larger one.
2) The use of edhesives3 for mounting the condensing lenses
and negative gate glass planes will make the price of replacement
lenses and plates unnecessarily high. It seems desirable-to
question this means of mounting glass damponents which should be
readily replaceable.,..:' :? ;.
3) Operating procedures are suggested^tor minimizing the
fluid gate bubble problem.
?;} Test procedtirerr, #re suggested for`quickl.y determining the
location of ti oubl a -ic'e .as t''hea he . optical t
~~v or s%i;s 4i =_, A in u the ey ?s3c
a. 11 -
crass ery Derr i Chs.nr,es
} The c,pxin ;-rroun;,.~~2 glass plate asiserfo y of the negative
gate, which is attach d to the front of the lsmphouse, must be
re-designed to facilitate easy removal for cleaning end occasional
replacement. The present plate already contains several mama.!2
aurfaee pits arid scrntchz :. This plate is cemented to a rubber-
gealecl, spring-mounted metal plate which will require a fairly
for disassembly project to remove. (Item 10 rig. 11, page 27,
of the Preliminary Instruction Manual)
. 4... Wit.
NGA Review Complete
Approved For Release 2004/11/30: CIA-RDP78B04770A0005b001?OQ35`9
 Approved For Release 2004/11/30 : CFA-RDP78B04770A000500010035-9
SUBJECT: Report on Optical and Fluid Gate Problems with the
Briefing Print Enitaxger
2) The vapor shield (item 5, fig. 9) page 22) must be re-
designed to give the operator more room to see and'guide the film
in the negative. gate. Two f%;11 clays of experimental testing of
the fluid gate has shown that for acceptable performance, the film
,positioning cannot consistently be accomplished-hands-off as
intended by the design. The problem is the bubbles which become
entraped in the gate and appear in the image.."This difficulty
is most pronounced when:
a) projecting at low magnification (because the entire
gate area is projected).
b) the center of the film is below th* center of the
film gate. (The film positioning spring-fingers prematurely
push the film forward against the glass stage plate, excluding
the fluid). .
c) using the new immersion fluid which contains ethanol.
-(the old 1020-40 enlarger fluid performs much better).
It has been determined that the bubble problem is minimized
when the operator uses his fingers to manually hold the film free
of both glass plates during both fluid injection and gate closure.
This even works well when the top edge of the film is below the
nozzles. The present vapor shield is in the way for best accom-
plishing this. The vertical. stainless steel plate on each side
of the lamphouse should be re-shaped to provide more clearance
for both seeing and for reaching in closer to the film gate.
3) The'band crank for positioning the lamphouse (item 3,
fig. g, page 22) must be replaced with one of larger diameter.
The present crank does not offer sufficient mechanical leverage
for best accomplishing the necessary slow and steady closing of
the film gate. :
C. Desirable Design Changes
.1.) It seems desirable from an economical viewpoint that
the mounting means for sli of the condenser lenses and possibly
the negative gate glass plates should be re-designed. At present
these optical components are all cemented and/or set in a rubber
ty e compound and because of this individual glass elements cannot.
be replaced easily. A spare set of all the optical components
should be kept on hand. Several new ones are already needed.". Li
Approved For Release 2004111/30 : CIA-RDP78B0477CA000500010035-9
 Appr4rved For Release-2004/11/30 : CIA-RDP78BO477OP00050d010035-9.
SUBJECTS Report on Optical and 'laid Gate Problems with the
Briefing Prin* Enlarger
0
present design will require-purchasing an as embl.y of glass Akan n ,
and machined zr t~ l housing/. The older spring clip m6thod of attach.
ing the glass components :'rould eliminate the need to purchase such
expensively machined mounting elutes along with' each optical component.
Of course, we roust remember that there is a fluid sealing require-
ment associated with the n -t'., e;ate glass plates which tray
justify keeping the adhesive concept for these plates. (howeY r
the re.-design as specified in R(1.) above is still a necessity.) $
The Dust Problem
1) Dust and other foreign matter would be a monumental.
problem with this enlargers due to the use of specular illuminav?on.
were it not for the saving feature of the liquid gate. Of course,
the environment should be kept as clean ad' possible., The procedure
described in B(2) above for obtaining a full injection of fluid
also helps..
2) When an objectionable spot does appear in the image, and
fluid will not move it, the following procedure may be used to
quickly determine its origin so that the offending foreign matter
may be removeds
a) Rack the lanrphouse back so only the film and fixed
stage glass remains in the focal plane. Wiggle the film,
Those spots in the image which wiggle are caused by spots on
the film. Any remaining spots which do not wiggle are due to
dirt or glass defects on the glass stage plate,
b) Move the ls,mphouse forward so the spring loaded
,la3s prosrure plsf:~ is not quite fully seated, R= etch in
b t'o7e T"l 7: he din i'nd i ale the side of this spring.
loved plate again watch for spots in the Image that
move. 713y will be on this glace plate,
c) Oth=,r low-contrast out-of-focus marks in the iMEV e
are probably caused try the condenser lens nearest the film
gate. The condenser assembly can be moved up and down very
r,ligbtly to verify this, (Several condensers are badly
nrured and need to '.e dis-assembled and cleaned. Also a
few contain nwnen'oue fine scratches 'end should already be
replaced.)
Three dr:?sign changes ar"! ;considered necessary before ttcCeptab)e
Approved For Release 2004/11/30 : CIA-RDP78BQ4770A000500010035-9.
STAT
 Approved, For Release 2004/11/30 : CIA-RDP78B04.7.70A0005p0d100.35-9',
- (CT: I3^port on Oppti(t. ax luid Gate Problem8 with the
Briefing Print Ear] a ~; r?
'armancc crtn be expected. Th-:!y two not drastic ones and could be
:-.c -) p].isbed by the r,ranuf netrsre? %ithout taking the B out of service.
r.t.,t sub-assemhiies could be pro juced and delivered for replacement.
It is also recommended that consideration be given to the desirable
but not necessary change of section C above.
It is further recommended that the operators be instructed to
try out &'d further evaluate the operating procedures contained
n) ; ,ribution:
Original - Dep. Asst,; for TD
1 .. Ch/EPS
1 : Ch/PLB`PSD
2 - TDS/XDL
STAT
STA
Approved For Release 2004/11/30 : CIA-RDP78B04770A000500010035.-9