3,731,612
1 2
PHOTOGRAPHIC DEVELOPING DEVICE 15 in which the radiation source 12 is supported. One
The invention herein described was made under a suitable source of radiation is a 650 watt DVY
contract with the United States Air Force. Quartzline (Registered Trademark) sun gun. Vertical
This invention relates to a cold red light source of il- sidewalls 16 may enclose a square, rectangular, oval or
lumination to be used in photochemical development 5 cylindrical or other configured space. Adjacent to the
of non-silver organic free radical films, as described in f,im ^ positioned between the film plane and the
U.S. Pat. No. 3,510,300 and in 3,573,046 and is an im- iower end of enclosure 10 is a support or shelf 18 for
provement of the photochemical developing apparatus one or more Wratten type fllters or other transmission
described in U.S. Pat. No. 3,573,046 and in U.S. Pat. filters 20.
application Ser. No. 766,160, filed Oct. 9, 1968, now 10 In ,ine with the axis passing through the radiation
Pat. No. 3,618,504 the disclosures of which are m- source and preferably at an angle of 45° to the plane of
tended to be incorporated herein by reference. filter 2Q is the first series of dichroic fllters 26, 28.
Free radical photographic systems have the unique To ... a substantial portion of the heat and to
advantage that the latent image can be developed by ... ^ ^ 2Q from overheating and fracturing) a
flooding the entire film with radiative energy in the red fon ^ ^ kioned in an Q ; in wa„ 16 Fan 24 ex.
or infrared region. A latent image dye is formed from i u * J • r *u i I«j i
f , ... .... pels heated air from the enclosure 10 and sucks air into
its precursors by the original exposure to visible or near , . „ „, , , „ , .
, J\. _, , the enclosure from the filter end thereof, thereby ef
ultraviolet light. It appears that the dye, m turn, has the . . _ . . , , „ „„ „,
....^ ,, •. ,. . . , , ^ , fectmg a flow of air along the surfaces of filters 20,26,
ability to absorb red and/or infrared photons and use 7 . , , ,
them to form additional dye molecules from neighbor- 20 28 Fan 24 also sucks a,r into the ^osure past the
ing dye precursors. Less light of shorter wavelengths sou'ce 12 and ultimately all the air IS expelled from the
& n C* i l T*^
during development allows more development before
the fog level reaches the maximum allowable. Less As shown ln FIG- 11 is Purred to utilize two
radiation of longer wavelengths reduces thermal fog. - dichroic fllters 26,28, one of which serves to determine
In order to obtain optimum results in the develop- the short wavelength cutoff and the other of which can
ment of free radical films, it is necessary to utilize a be used to determine the long wavelength cutoff. A
high intensity source for the radiation provided for third dichroic, if used, may be the same as the first or
development and such sources usually provide a large last filter, depending on which end of the waveband is
amount of heat in addition to the desired radiation. The 30 intended to have the sharpest cutoff,
heat may be considered "noise", and in contrast to the It is also possible to provide only one dichroic filter
desired actinic radiation which is "signal". which will provide a gradual cut off and cut on of the
One object of the invention is to provide develop- wavelengths of the radiation from the source 12.
ment radiation having a high signal-to-noise ratio of ac- As shown in FIG. 1, the radiation passed by the
tinic to visible intensities and actinic to infrared intensi- 35 dichroics can be further modified by the use of one or
ties. more of the usual Wratten fllters, disposed to receive
Another object of the invention is to provide the red radiation from which most of the IR and heat have been
and near-infrared radiation for development of organic removed. The relatively delicate Wratten filter 20 is
free radical films in a manner that is more effective and positioned downstream from the dichroics 26, 28.
more uniform than has heretofore been possible. 40 Heretofore, the Wratten filters were not usable in a
Another object of the invention is to provide a sim- practical sense because of the heat generated and
pier and more versatile apparatus than the prior art ap- pasSed from the previously used radiation sources,
paratus noted above. -rj,e apparatus includes means for positioning a film
Still a further object is to provide an apparatus in to be phot0chemically developed into the path of the
which the peak sens.tivity of the developing radiation is 45 radiation passed by tne tram of fllters. Any suitable
readily changed to accomodate ^ sens.tiv.- ... may bg provided for bringing individual expo.
^ J?^.!?16 PaTl*cu^T fi'm_ eing processe . sures or a reel may be passed out intermittently by any
Still another obiect is elimination of the water niter, . . c ...
. J „ . , , . conventional film feeding means,
and mechanical drive of previously known units and to ,. , . . ■ . f ,„ rwi/
, - , , . • ■ en The dichroic unit consists of a 650 watt GE DVY
provide an apparatus for simultaneously achieving ■ c 1 • c o . • i_ ■
v . . , _ , Z tungsten lamp in a Sylvania Super 8 sun gun which is a
greater intensity, more uniformity, better control of ° . . r v. .. ..
0 w t. „. , .,. well optimized tungsten source for radiometric intensi
waveband, higher signal-to-noise ratio, operating with , \ , ...
Iower wattage and less heat output, thereby yielding *tm the red' and c°»ect.on for projection through a
higher photo speeds, more latitude for gamma control relat.vely small aperture. The halogen cycle, however,
and better general appearance of the free radical films 55 insures relatively constant color temperature until a
developed. relatively sudden burn out.
These and other objects are accomplished by the use A fan 24 is positioned to cool both the lamp from
of the method and apparatus hereinafter described back to front and the dichroics and cut-off filter by
taken in connection with the drawings in which: pulling air into the apparatus. The filters are positioned
FIG. 1 is a schematic plan view of a preferred ap- 60 to prevent any stray light from the lamp house from by
paratus; and passing both dichroics and still hitting the film platen
FIG. 2 is a graphical representation showing the directly,
radiation provided by the apparatus of FIG. 1. Utilizing Kodak No. 301 dichroics in the apparatus
Briefly, the apparatus includes an enclosure 10 hav- ^ described has been found to effectively dump the heat
ing a source of radiation 12 mounted at one end of the beyond 700 nm so that glass filters, especially the ab
apparatus, opposite the end at which a film F is exposed sorbing type, no longer break from its absorption
to the radiation. The enclosure comprises an upper well beyond 900 nm.
