Table Of ContentA 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
