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Development of motion picture film by the reel and tank system
Dec., I923.]
EASTMAN KODAK COMPANY NOTES.
82 7
concluded that the d i s a g r e e m e n t a m o n g different observers is due rather to the samples e x a m i n e d than to the m e t h o d s of analysis employed. I n addition, the lattice constants of silver chloride, silver b r o m i d e and metallic silver were remeasured. T h e results are s u m m a r i z e d in the following table: Side of Distance elementary apart of Crystal. Lattice unit of nearest structure, structure in atomic kngstroms, eentres. Silver chloride Simple cubic 5.540 2.770 Na-C1 type Silver bromide
Simple cubic Na-CI type
5.768
2.884
Silver iodide
Diamond cubic Zn-S type
6.493
2.812
Silver i o d i d e
Hexagonal Zn-O type
Metallic silver
Face centred cubic
4.593 (c/a = 1.633) 4.o78
2.813 2.884
A L A B O R A T O R Y F R A C T I O N A T I N G COLUMN.' By H. T. Clarke and E. J. Rahrs.
A FRACTIONATING column constructed entirely of glass tubing a r r a n g e d with suitable indentations. A cooling unit at the head provides for the desired a m o u n t of return flow. E x p e r i m e n t a l figures show that a b o u t half of each c o m p o n e n t of an equal m i x ture of benzene and toluene can be obtained nearly pure on the first distillation. D E V E L O P M E N T OF M O T I O N P I C T U R E FILM BY T H E R E E L AND TANK SYSTEM: By J. I. Crabtree.
THIS article deals exhaustively with the handling of motion picture film by the reel and tank systems d u r i n g the operations of developing, fixing, washing, and drying. T h e i n f o r m a t i o n is classified as follows: 4 Communication No. I67 from the Research Laboratory of the Eastman Kodak Company and published in Ind. Eng. Chem., April, I923, p. 3495 Communication No. I87 from the Research Laboratory of the Eastman Kodak Company and published in Trans. Soc. Mot. Pict. Eng., May, I923, p. 163.
828
t~ASTMAN KODAK COMI'ANY NOTES.
[J.F.I.
( I ) Apparatus.--The various types of racks, reels, tanks, and troughs are described and illustrated, the layout of a typical development room is given and the materials suitable for construction of such apparatus are discussed. (2) Chemical SolutioJ1s.--Developing and fixing solutions are discussed in respect to their preparation, photographic properties, life, and methods of revival. Formulas, which fulfill the various requirements, are given. (3) Manipulative Details.--Detailed instructions are given for dealing with various types of motion picture fihn, together with the control tests and variations in treatment under different conditions. (4) Troubles.--Troubles which are commonly met with in each process are listed with suggestions for their prevention and removal.
N O T E ON T H E T H E O R Y OF P H O T O G R A P H I C S E N S I T I V I T Y . ' By S. E. Sheppard and E. P. Wightman.
THE theory that the latent image consists of colloidal silver and that there are, also, present in the grain,, prior to exposure, colloidal silver specks, which form development centres by exposure, are discussed, and experimental evidence is given that such preexistent specks do occur and that they are distributed both inside the grain as well as on the surface. It is supposed that the first action of the light is to release a photo-electron from the colloid silver speck, that the free electron, having a free kinetic energy I/4mv 2= hv, where v is the frequency of the active light, is then able to enter the silver ion, forming a neutral silver atom, while the unneutralized bromide ion loses an electron. This chain reaction, analogous to that suggested by Bodenstein, for the action of light on hydrogen and chlorine, would go on to a limiting state, depending on the initial energy of the photo-electron, but producing a nucleus large enough to initiate development for a developer of given reduction potential. 6Communication No. 185 from the Research Laboratory of the Eastman Kodak Company and published in Science, August 3, 1923, pp. 89-91.
EASTMAN KODAK COMPANY NOTES.
82 7
concluded that the d i s a g r e e m e n t a m o n g different observers is due rather to the samples e x a m i n e d than to the m e t h o d s of analysis employed. I n addition, the lattice constants of silver chloride, silver b r o m i d e and metallic silver were remeasured. T h e results are s u m m a r i z e d in the following table: Side of Distance elementary apart of Crystal. Lattice unit of nearest structure, structure in atomic kngstroms, eentres. Silver chloride Simple cubic 5.540 2.770 Na-C1 type Silver bromide
Simple cubic Na-CI type
5.768
2.884
Silver iodide
Diamond cubic Zn-S type
6.493
2.812
Silver i o d i d e
Hexagonal Zn-O type
Metallic silver
Face centred cubic
4.593 (c/a = 1.633) 4.o78
2.813 2.884
A L A B O R A T O R Y F R A C T I O N A T I N G COLUMN.' By H. T. Clarke and E. J. Rahrs.
A FRACTIONATING column constructed entirely of glass tubing a r r a n g e d with suitable indentations. A cooling unit at the head provides for the desired a m o u n t of return flow. E x p e r i m e n t a l figures show that a b o u t half of each c o m p o n e n t of an equal m i x ture of benzene and toluene can be obtained nearly pure on the first distillation. D E V E L O P M E N T OF M O T I O N P I C T U R E FILM BY T H E R E E L AND TANK SYSTEM: By J. I. Crabtree.
THIS article deals exhaustively with the handling of motion picture film by the reel and tank systems d u r i n g the operations of developing, fixing, washing, and drying. T h e i n f o r m a t i o n is classified as follows: 4 Communication No. I67 from the Research Laboratory of the Eastman Kodak Company and published in Ind. Eng. Chem., April, I923, p. 3495 Communication No. I87 from the Research Laboratory of the Eastman Kodak Company and published in Trans. Soc. Mot. Pict. Eng., May, I923, p. 163.
828
t~ASTMAN KODAK COMI'ANY NOTES.
[J.F.I.
( I ) Apparatus.--The various types of racks, reels, tanks, and troughs are described and illustrated, the layout of a typical development room is given and the materials suitable for construction of such apparatus are discussed. (2) Chemical SolutioJ1s.--Developing and fixing solutions are discussed in respect to their preparation, photographic properties, life, and methods of revival. Formulas, which fulfill the various requirements, are given. (3) Manipulative Details.--Detailed instructions are given for dealing with various types of motion picture fihn, together with the control tests and variations in treatment under different conditions. (4) Troubles.--Troubles which are commonly met with in each process are listed with suggestions for their prevention and removal.
N O T E ON T H E T H E O R Y OF P H O T O G R A P H I C S E N S I T I V I T Y . ' By S. E. Sheppard and E. P. Wightman.
THE theory that the latent image consists of colloidal silver and that there are, also, present in the grain,, prior to exposure, colloidal silver specks, which form development centres by exposure, are discussed, and experimental evidence is given that such preexistent specks do occur and that they are distributed both inside the grain as well as on the surface. It is supposed that the first action of the light is to release a photo-electron from the colloid silver speck, that the free electron, having a free kinetic energy I/4mv 2= hv, where v is the frequency of the active light, is then able to enter the silver ion, forming a neutral silver atom, while the unneutralized bromide ion loses an electron. This chain reaction, analogous to that suggested by Bodenstein, for the action of light on hydrogen and chlorine, would go on to a limiting state, depending on the initial energy of the photo-electron, but producing a nucleus large enough to initiate development for a developer of given reduction potential. 6Communication No. 185 from the Research Laboratory of the Eastman Kodak Company and published in Science, August 3, 1923, pp. 89-91.