A study of the development and application of sensitometry in motion picture film processing laboratories

127 Pages·05.722 MB·English

by  Trvedi, Rhupendra

A STUDY OF THE DEVELOPMENT AND APPLICATION
OF SENSITOMETRY IN MOTION PICTURE FILM
PROCESSING LABORATORIES
A Thesis
Presented to
The Faculty of the Department of Cinema
The U niversity of Southern C alifornia
In P a rtia l Fullfllm ent
of the Requirements for the Degree
Master of Arts in Cinema
by
Bhupendra Trivedi
August 1950
UMI Number: EP42705
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CIT) s I TBfl
This thesis, written by
.....................B httP .e»iira...T ri3ra d i.................................
under the guidance of h..iS_. Faculty Committee,
and approved by all its members, has been
presented to and accepted by the Council on
Graduate Study and Research in partial fulfill­
ment of the requirements for the degree of
Master of Arts
OCT 17 (950
Date.
Faculty Committee
Chairman
•tabu; of contents
CHAPTER PAGE
I. INTRODUCTION .................. 1
The problem ............................................... 1
Statement of the problem .................. 1
Importance of the study .................... 1
Method of procedure ......................................... 2
I I . THE CHARACTERISTIC CURVE .............................. 4
Latitude ................C . .................... 7
Gamma .............................. 8
Time - Gamma curves ........................................ 8
* F o g ................................ 12
Reciprocity law and the ionic conductivity
of silv e r halides .................................. 15
Reciprocity law a t high in ten sity . . . . . . . 16
R eciprocity law at low intensity . . . . . . . . 17
I I I . SENSITOMETERS AND DENSITOMETERS .............. 19
Light source .............................. 21
Sensitom eters ............................ 25
In ten sity scale instrum ents .......................... 85
Time scale instrum ents ...................................... 29
H urter and D riffield sensitom eter ........... 31
Scheiner sensitom eter ................................... 33
Eastman sensitom eter type I I b ..................... 33
lv
CHAPTER _ _ PAGE
Densitometers . . . . . ......................... 26
Diffuse and Specular density .......... 38
Subjective and objective type
densitom eters ............................ 39
Gapstaff - Green densitom eter ........................ 41
Capstaff - Purdy densitom eter ................. 43
M artens p olarization d en sito m eter............... 43
General requirements of the densitom eter . 45
IV* APPLICATION OF SENSITOMETRY IN
PROCESSING LABORATORIES..................... 47
Determination of the time of development
fo r the required gamma ...................................... 48
Solution control ................................... 50
P rinting and processing the positive
f i l m .................................................................... 52
Motion picture tim er ........... 53
Methods to determine the p rin tin g
exposure ................... 54
P r in tin g ............................................................................ 55
Sound processing ............................ 58
Variable density re c o rd in g ................ 60
V ariable area recording ...................... 65
U ltra - vio let lig h t in sound recording ., 68
CHAPTER - - . . . PAGE
Resolving p o w er-...-,....................................... 71
Processing and p rin tin g ................... 73
V. EMULSION SPEED AND ITS MEASUREMENTS . . . . . . . . 75
In e rtia speed ratin g ................................. 75
Evaluation of photographic speed from
the H & D curve ............................................. 80
Device to read the speed d irectly
from the ch a ra cte ristic curve 82
D irect visual m ethod ............... 87
D irect photometric method ............................... 90
Sources of erro rs in d ifferent methods . . . 91
Threshhold speed ................ 93
A comparison between the two systems. . . . . 94
A* S. A, sy ste m .............. 95
VI, COLOR DENSITOMETRY.......................... 96
Equivalent density ..................................................... 96
Spectral density ................ 99
Evan's densitom eter ............................................ 100
Ansco model II ....................... 103
Western E lectric RA - 1100 densitom eter .. 107
VII* SUMMARY AND CONCLUSIONS .............................................. 112
Summary .............................. 112
Conclusions ................... 113
BIBLIOGRAPHY................................................. HA
XIST OP FIGURES
FIGURE RAGE
Ii The ch aracteristic curve of ah emulsion
showing the relatio n between density
and log^o exposure *.............. 5
I I . Time - gamma curves . . . . . . . . . . . . . . . . . . . . . . 9
III* The general form of the f ir s t derivative
of the D log E curve 11
IV* Curves for several photographic m aterials
- showing the fa ilu re of the reciprocity
la w ................................. 14
V* The essen tial parts of any photographic
sensitom eter ........... Q 20
VI. Spectral se n sitiv ity of the normal human
eye ................ 25
V II. Reproduction of te st made with Luthe’s
crossed wedged sensitom eter .......... 28
V III. Sector wheel in Soheiner's sensitom eter .. 30
IX. Sector wheel in Hurter and D riffield
sensitom eter ........................................................ 32
X. Eastman sensitom eter type I I 34
XI * Diffuse - Specular density 37
X II. Capstaff - Green densitom eter ................... 40
X III. C apstaff - Purdy d en sito m eter....................... 42
vii
FIGURE BAGS
XIV. M arten's polarization densitom eter . . . . . . . 44
XV* Tone reproduction diagram for sound
recording ........... 61
XVI* Time - gamma curves for (1) variable
density, and (2) V ariable area .............. 66
XVIIi Character1 stic curves for (1) variable
density, and (2) variable a r e a 67
XVIII* Transmission ch a ra cte ristic of (a) variable
area and density emulsion, (b) recording
f ilte r and (c) commercial sound -----
recording ..................................... 70
XIX, Resolving power and image density curve ., 72
XX, In e rtia point of a single ch aracteristic
curve .................................................*... 76
XXI. In e rtia point for a group of ch a ra cte ristic
curves . » , . . . . ..................................... 77
XXII* C haracteristic curve for the determ ination
of gradient speed point ................. 79
XXIII. A transparent meter fo r determining speeds
from the ch aracteristic curve ............... 85
XXIV* Two part wedged sensitom etric exposure . . . 86
XXV, The radiom eter used as a gradient meter ., 89
XXVI. The Threshhold speed ............................................... 92
viii
FIGURE PAGE
XXVII. Effect of im purities upon combined
density ............................................ 98
XXVIII. Ansco - model 11 ........................................ 101
XXIX. Evan’s densitom eter ........................ 104
XXX. Curves for the monochromatic f ilte r
- combination used in color densito­
meter .......................................................................... 106
XXXI. Western E lectric RA - 1100 densito­
meter .............. 108
(LIST OF TABLES
TABLE PAGE
I. Influence of photographic conditions
on the quality of sound reproduction . . . . 58