Title:
Photographic film developing apparatus
United States Patent 2237737


Abstract:
My invention relatesto apparatus for employment in developing photographic film, and is particularly adapted to be used in developing film according to the method invented by Frank E. Perry and known in the trade as the "P & H" method of development, In the method of developing photographic...



Inventors:
Houston, Herbert W.
Application Number:
US30120939A
Publication Date:
04/08/1941
Filing Date:
10/25/1939
Assignee:
HOUSTON CORP
Primary Class:
Other Classes:
242/530.2, 242/538.4, 242/547
International Classes:
G03D13/14
View Patent Images:



Description:

My invention relatesto apparatus for employment in developing photographic film, and is particularly adapted to be used in developing film according to the method invented by Frank E. Perry and known in the trade as the "P & H" method of development, In the method of developing photographic film above referred to, the photo-sensitive emulsion is preferably first contacted with a developing solution for a short time period sufficient to cause absorption by the emulsion of a limited quantity of developing solution sufficient only to develop the high-light portions of the exposed film to the desired density, and the film is then withdrawn from contact with the developing solution and is preferably sealed from the air and, while sealed, is throughout the principal development step allowed to develop by action of only the limited quantity of developing solution contained in the emulsion. By use of this method the apparent speed of a photographic film and the range of exposure over which good prints may be made are both greatly increased. Shadow detail is marvelously improved, definition is better, and grain is finer than when the film is developed by ordinary methods, It is an object of this invention, therefore, to provide an apparatus which is adapted to seal the emulsion of a film being developed and to retain it in contact with a smooth surface during the principal development step.

Another object is to provide apparatus for substantially sealing the emulsion of a photographic film from contact with air and for preventing light from striking the film while sealed and during the principal development step.

Another object is to provide apparatus for winding up a wet film and for removing excess liquid from the film.

Another object of the invention is to provide a film developing device in which film is wound and which has special provision for gripping the film during the first few turns of the winding.

A further object is to provide an apparatus in which film is adapted to be wound between successive layers of a smooth-surfaced tape and which comprises means for housing the tape prior to winding.

Still another object of the invention is to provide apparatus for developing photographic film which is easy to construct, and is convenient and dependable in use.

These and other apparent objects are attained in a manner which will be clear from a consideration of the following description taken in connection with the accompanying drawing, of which: Fg. 1 is an elevational view of one form of the apparatus of my invention, with the outer case member turned into the closed position wherein the chamber within is light-tight.

Fig. 2 is a cross-sectional elevational view of the apparatus of Fig. 1 with the outer case member turned into the open position.

Fig. 3 is a sectional view of the apparatus of Fig. 2 taken along the line 3-3, as indicated.

Fig. 4 is a sectional view of the apparatus of Fig. 2 taken along the line 4-4, as indicated.

Fig. 5 is a sectional view of an alternative device for gripping the film at the start of the winding operation.

Fig. 6 is a sectional view of an alternative form of my apparatus.

In the embodiment of my invention illustrated in Figs. 1 to 4, I provide an inner case member 10 comprising an end portion I, having its periphery formed to provide a base 12, and, rising from the end portion 1 , a centrally located spindle 13 and a cylindrical wall 14 open on one side at 15 over preferably about 140%. The spindie 13 is preferably pointed at its upper end at IS and supports a spool 11 which has a central hole therein fitting the spindle 1S in such manner that when the spool is in the lowermost position on the spindle, as in Fig. 2, it is freely rotatable on the spindle and has clearance from the end portion 1 . The spool 7 has extending from its upper end a cylindrical shaft portion 18 which terminates in a portion 22 of preferably square-section on which a knob 23 having a socket of corresponding shape is adapted to fit loosely. Fitting over and around the inner case 10 is an outer case member 24 having an end portion 25 with a central hole 26 therethrough to accommodate the shaft 18 and with a groove 27 within which is adapted to fit the upper end of the wall 14. A cylindrical wall 28 extends downwardly from the end portion 25 and encloses the wall 14 of the inner case, the interior diameter of the wall 28 being substantially the same as the exterior diameter of the wall 14. The wall 28 is, like the wall 14, open on one side at 30 over an angle approximately the same as that of the opening in the inner case wall.

The spool 17 has a slot 31 in its surface into which the end of a film 32 may be slipped and the film may then be wound on the spool. The film 32 is preferably wound with the emulsion 33 on the inside. Carried on the inside of the wall 14 and bearing on the film 32 which is wound on the spool I7 are a plurality of resilient vane, 36. Each of the vanes 36 is preferably made oi rubber, is tapered from a relatively thick sectior at the wall Il to a relatively thin section where it bears on the film 32 and is long enough to beai on the film 82 when only a single layer is wounc on the spool 17. The vanes S6 are preferably supported from the wall 10 in sockets or grooves 3S, into which they are pressed from the end.

It will be evident that the outer case 2( may be rotated on the inner case 10 to make the openings 15 and 36 register with one another to give access to the spool I7, or may be rotated into closed position, as in Fig. 1, wherein the opening 1 is covered by the opaque wall 26 and the opening 30 overlies the opaque wall 14. In order to limit the travel of the outer case 26 relative to the inner case 10, the groove 27 is widened at 34 over an angular portion of its circumference greater than the openings I5 and 30 and a protuberance 38 is formed on the inner surface of the wall 14 so as to project into the widened portion 34 of the groove. The protuberance 35 is located in such a position that when the inner and outer cases 10 and 2l are positioned relatively so as to make the openings 1S and 30 overlap to provide access to the spool T 7 the protuberance 35 is at one end of the widened portion 38 of the groove, and that when the protuberance 35 is at the other end of the widened portion 30 of the groove the inner and outer cases 10 and 21 are positioned relatively so that both openings I and 30 are covered. When the protuberance is at either end of the widened portion 36 of the groove it may be wedged in the narrowing groove to frictionally retain the inner and outer case members in fixed position against accidental relative rotation.

In the use of the apparatus of my invention, the film to be developed is first preferably immersed in developing solution for a suitable short period of time to cause the emulsion to absorb a suitable quantity of solution. The outer case 24 of the apparatus is rotated on the inner case 10 in the opening direction as far as it will go.

The openings 15 and 30 then coincide as in Figs. 2, 3, and 4. The end of the wet film is then introduced into the slot 31 on the spool I7 and the knob 23 is turned in such a direction as to wind up the film 32 on the spool. The vanes 36, bearing on the film base as the film is wound up, removes excess liquid from that side of the film and presses the emulsion of the oncoming film tightly against the base of the underlying film layer to remove excess liquid from the emulsion side also. The pressing of the vanes 38 on the film as it is wound up assures a tight winding of the film on the spool and maintains the film ip tightly wound condition. When all of the strip of film to be developed has been wound on the spool I, the outer case 2H is rotated in a clockwise direction, as seen in Fig. 3, until the protuberance 35 comes to the other end of the widened portion 3( of the groove in which it travels and is wedged in the narrowing groove to hold the inner and outer cases in the closed position in which no light is permitted to reach the developing film on the spool 1T.

It will be seen that when wound on the spool IT the emulsion 33 of the film is sealed in contact with the smooth base of the underlying film, ordinarily Celluloid or cellulose acetate, and is sealed from contact with the air. *During the principal development step the film is left wound on the spool I7 for a suitable time period which s may vary from 15 minutes or less to an indeff initely long time. A feature of the method of I development for which the disclosed apparatus S is particularly adapted is that the film may be left in contact with the limited quantity of deS veloper which it contains for very long periods r of time without disastrous results. The film may, for example, be left wound on the spool IT overnight if desired. Development can only proceed to a definite limiting degree. During this development step the device, with the film inside, may, if desired, be removed from the dark room as no light can get into it. When development has proceeded for a suitable time period, the film 82 is removed from the apparatus. This is preferably done by removing the knob 28, loosening the outer case 26 from its wedged position relative to the inner case 10 and lifting the outer case 20 off of the inner case and the shaft 18. The spool 17 with the film 32 wound on it can then be lifted off the spindle 13 and the film can be unwound from the spool and fixed, washed and dried as in ordinary practice. The spool I' may then be replaced on the spindle 18, the outer case 26 may be installed over the inner case 10, the knob 23 may be placed on the squared end 22 of the spool shaft, and the apparatus is again ready to be used in the development of another strip of film.

so Instead of securing the end of the film 32 in the slot 31, I may alternatively employ the arrangement illustrated in Fig. 5. The end of a short tape (0, preferably of celluloid or of cellulose acetate, is slipped into the slot 31 and wound preferably once around the spool I7 leaving a short end free. The end of the film 82 to be developed is inserted between this free end of the tape and the tape layer already wound on the spool and the spool is then turned to wind the film 32 first between the successive tape layers and then, after the tape has run out, upon itself. The spool 17 is, of course, located on the spindle 13 during this action and the construction of the remainder of the apparatus and the operation thereof are in all other respects the same as previously described.

In the embodiment of my invention illustrated in Fig. 6 I wind the entire length of film 82 to be developed between successive layers of a tape a2, preferably made of Celluloid or of cellulose acetate. This is superior to winding only the end of the film between the successive tape layers as in Fig. 5 especially in the case of films which do not have any substantial unexposed portion at the ends thereof but in which pictures extend down practically to the ends of the strip.

In the embodiment of Fig. 6 there is no chance for any irregularity of development such as might exist at the end of the strip 48 in the embodiGo ment of Pig. 5 if this should fall over an exposed picture area of the film. In the embodiment of Pig. 6, the member corresponding to the inner case member I0 of Figs. 1 to 4 is the member 43 having in this embodiment a base portion supporting not only the cylindrical wall 1I and the spindle 83, as in the embodiment previously described, but extending outwardly to the side and supporting a cylindrical container 66 having a slot 41 extending longitudinally along one side thereof adjacent the opening through the wall 14. The top of the container 84 is preferably left open. The wall 14, as in the previously described embodiment supports the resilient vanes 36, and the outer case member 28 fits over the wall 1s and has an opening therein which can by rotation of the outer case 24 be made to register with the opening in the wall 14 to permit entrance of the film 32. The outer case can also be rotated to cover the openings through both the walls 14 and 28 to prevent any light from falling on film which is wound on the spool 17.

The protuberance 35 moves in a widened groove as in the embodiment previously described and limits the relative rotation of the inner and outer cases. It will be apparent that the only difference between the embodiment of Fig. 6 and that previously described is in the provision of the long tape 42 and the container 44 adjacent the opening which provides access to the spool.

In using the apparatus illustrated in Pig. 6, a roll of tape 42, preferably of Celluloid or of cellulose acetate, is placed within the container 44 and the outside end of the roll is brought through the slot 45 and through the openings in the walls 28 and 14, and is slipped into the slot 31 in the spool 17. The spool is then turned through one or more revolutions so as to cover the surface of the spool with the tape 42. The wet film 32 containing the required amount of developing solution is led onto the spool 17 between the successive layers of tape 42 and the spool is rotated to wind both the film and the tape onto the spool. Rotation of the spool is continued until all of the film and the tape is wound up on the spool, and the outer case 24 is then rotated to cover the openings in the walls 14 and 28 and the film is left to develop. The tape 42 is preferably longer than the strip of film 32 which is to be developed, so that when wound on the spool all of the film lies sealed Z between the successive layers of the smoothsurfaced tape 42. In winding the film and tape onto the spool, the vanes 36 bear on the outer layer of the winding, which is the tape layer, and not only remove any excess liquid from the 4 wet film 32 and its emulsion, but also assure a tight winding on the spool and maintain the film and tape tightly wound until the spool is removed. Following a suitable development period the spool 17 is preferably removed as pre- 4 viously described in connection with the embodiment of Figs. 1 to 4 and the tape 42 and film 32 are unwound from the spool. The tape 42 is preferably dried and may then be replaced in the container 44. Following re-assembly of the 5& apparatus, as previously described, it is ready to receive another strip of film to be developed.

The members 10, 24, and 43, as well as the spool 17 and the knob 23 are all preferably molded of substantially opaque synthetic resin 5' or equivalent material.

It will be understood that the axial length of the units may be made to fit films of various widths, or that the length may, if desired, be made suitable for accommodating several film 6c strips side by side. It is also understood that various other changes and modifications in design and construction may be made without departing from the spirit and scope of the invention as defined in the appended claims. I claim as my invention: 1. In photographic film developing apparatus, the combination of: a case comprising two relatively rotatable parts with adjacent cylindrical walls having openings therein which in one relative position of said parts overlap to provide access to the space within said case, and in another relative position of said parts are both covered to substantially prevent entrance of actinic light into said space; a spool rotatably mounted within said case for the winding thereon of film to be developed; means outside of said case in rotative connection with said spool; and a plurality of rubber wedge-shaped vanes supported In sockets on the Inner of said cylindrical walls, said vanes being adapted to bear on the outer layer of the winding on said spool over substantially the entire width thereof.

2. In photographic film developing apparatus, the combination of: an inner case member including a base, a cylindrical wall carried on said base and having an opening therein, and a spindte supported by said base and extending along the axis of said wall; an outer case member comprising an end portion and a cylindrical wall joined thereto and fitting over the cylindrical wall of said inner case member in such manner as to be rotatable thereon, said cylindrical wall of said outer case member having an opening therein adapted in one relative position of said members to register with the opening in the cylindrical wall of said inner case member; a spool rotatably mounted on said spindle for the winding thereon of film to be developed, said spool having a shaft which extends through said end portion of said outer case member; and vanes of resilient material supported on said cylindrical wall of said inner case member and adapted to bear on the outer layer of the winding on said spool.

3. In photographic film developing apparatus, the combination of: an inner case member including a cylindrical wall; an outer case member including a cylindrical wall fitting over said 15 cylindrical wall of said inner case member and being rotatable thereon, both of said walls having openings therethrough adapted in one relative position of said members to register to provide access to the space within; walls formSing a groove in one of said members adjacent the end of the cylindrical wall of the other of said members, said groove extending only part way around said cylindrical wall; a protuberance on the cylindrical wall of said other of said members , extending into said groove, said protuberance being so located that when it is at one end of said groove said openings register but when it is at the other end of said groove said openings are covered; a spool rotatably mounted on the 3 axis of said cylindrical walls for the winding thereon of film to be developed; and resilient vanes adapted to bear on the outer layer of the winding on said spool.

4. In photographic film developing apparatus, Sthe combination of: a case comprising two relatively movable parts having openings therein which in one relative position of said parts overlap to provide access to the space within said case, and in another relative position of said I parts are both covered; a spool rotatably mounted within said case; means-outside of said case in rotative connection with said spool; a smooth-surfaced tape wound on said spool in such manner that the film to be developed may be introduced and wound between successive layers of. said tape, and means adapted to resiliently bear on the outer layer of the winding on said spool.

5. In photographic film developing apparatus, the combination of: a case comprising two relatively movable parts having openings therein which in one relative position of said parts overlap to provide access to the space within said case, and in another relative position of said parts are both covered; a spool rotatably mounted within said case; means outside of said case in rotative connection with said spool; a smooth-surfaced tape wound on said spool in such manner that the film to be developed may be introduced and completely wound between successive layers of said tape; means supported by one of said parts of said case adapted to bear resiliently on the outer tape layer wound on said spool; and a container adapted to house tape to be wound on said spool, said container having a slot therein adjacent said overlapping openings for passage of said tape from said container to said spool.

6. In photographic film developing apparatus, the combination of: an inner case member including a base, a cylindrical wall carried on said base and having an opening therein, and a spindle supported by said base and extending along the axis of said wall; an outer case member comprising an end portion and a cylindrical wall joined thereto and fitting over the cylindrical wall of said inner case member in such manner as to be rotatable thereon, said cylindrical wall of said outer case member having an opening therein adapted in one relative position of said members to register with the opening in the cylindrical wall of said inner case member; a spool rotatably mounted on said spindle and having a shaft which extends through said end portion of said outer case member; a smooth-surfaced tape wound on said spool in such manner that the film to be developed may be introduced and completely wound between successive layers of said tape; a container adapted to house tape to be wound on said spool, said container being supported by said base of said inner case member and having a slot in the wall thereof adjacent the registered openings of said members for passage of said tape from said container to said spool; and vanes of resilient material supported on said cylindrical wall of said. inner case member and adapted to bear on the outer tape layer wound on said spool.

HERBERT W. HOUSTON.