Dye fading during archival storage of developed color photographic film is retarded by placing the film in a sealed, opaque vault, introducing a dry, pressurized inert gas into the vault while the latter is vented, and sealing the vault after the air within the vault has been purged and replaced by the inert gas. Preferably, the gas is nitrogen; and the vault is stored at a temperature below room temperature to preserve the color photographic emulsions on the film contained within the vault. For short-term storage, sodium thiocyanate pads charged with water are placed within the vault. For long term storage, the interior of the vault is kept at a low relative humidity

Hoover, R. B.

Rhodes, C. M.

English

NASA Technical Reports Server

United States Patent 1191 
Hoover et al. 
[54] METHOD OF FOR RETARDING DYE 
FADING DURING ARCHIVAL STORAGE OF 
DEVELOPEDCOLORPHOTOGRAPHIC 
FILM 
[75] Inventors: Richard B. Hoover; Charles M. 
Rhodes, both of Huntsville, Ala. 
[73] Assignee: The United States of America as 
represented by the Administrator of 
the National Aeronautics and Space 
Administration, Washington, D.C. 
[21] Appl. No.: 119,340 
1221 Filed: Feb. 7,1980 
[51] Int. C l . 3  ......................... BOlJ 19/14; BOlJ 19/00 
[52] U.S. c1. ........................................ 422/40; 430/17; 
430/372 
[58] Field of Search ............... 422/9, 10, 40; 430/372, 
430/644 
[561 References Cited 
U.S. PATENT DOCUMENTS 
2,605,164 7/1952 Ode11 ......... ........................ 422/40 
2,647,057 7/1953 Seary et al. .......................... 430/372 
2,661,603 12/1953 Trask ................................. 422/40 X 
[111 4,287,152 
[451 Sep. 1, 1981 
3,704,088 11/1972 Nagel et al. ............................ 422/10 
4,066,401 VI978 Solomon ................................ 422/40 
FOREIGN PATENT DOCUMENTS. 
2500374 7/1976 Fed. Rep. of Germany ............. 422/40 
52-29858 3/1977 Japan ......................................... 422/40 
Primary Examiner-Barry Richman 
Attorney, Agent, or Firm-Joseph M. Beumer; John R. 
Manning; Leon D. Wofford, Jr. 
1571 ABSTRACT 
Dye fading during archival storage of developed color 
photographic film (17) is retarded by placing the film in 
a sealed, opaque vault (lo), introducing-a dry, pressur- 
ized inert gas into the vault while the latter is vented, 
and sealing the vault after the air within the vault has 
been purged and replaced by the inert gas. Preferably, 
the gas is nitrogen; and the vault is stored at a tempera- 
ture below room temperature to preserve the color 
photographic emulsions on the film contained within 
the vault. For short-term storage, sodium thiocyanate 
pads (36) charged with water are placed within the 
vault. For long term storage, the interior of the vault is 
kept at a low relative humidity. 
2,788,274 4/1957 Ranger ............................. 430/372 X 
3,188,166 6/1965 Dietz et al. ............................ 422/10 6 Claims, 1 Drawing Figure 
https://ntrs.nasa.gov/search.jsp?R=19820003559 2020-03-21T15:34:24+00:00Z
U.S. Patent 
I i l  
Sep. 1, 1981 
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4,287,152 
N 
N 
4,287,152 
METHOD OF FOR RETARDING DYE FADING 
DURING ARCHIVAL STORAGE OF DEVELOPED 
COLOR PHOTOGRAPHIC FILM 
DESCRIPTION 
TECHNICAL FIELD 
The invention described herein was made by employ- 
ees of the United States Government and may be manu- 
factured and used by, or for, the Government for gov- 
ernmental purposes without payment of any royalties 
thereon or therefor. 
This invention relates to a method of and means for 
retarding dye fading in the archival storage of devel- 
oped color photographic film. 
BACKGROUNDART 
Prior to the present invention, developed photo- 
graphic film has been stored in totally uncontrolled 
conditions (e.g., in cabinets by amateur photographers), 
under limited control of temperature and humidity (e.g., 
50 degrees F. and 50% relative humidity such as in the 
Johnson Space Center film vault), or in cold-dry stor- 
age (0 degrees to -10 degrees F. at 15% relative hu- 
midity for motion picture film). Where the color film 
has relatively stable emulsions, such as Kodachrome 
film and Cibachrome film, the conventional arrange- 
ments for storing film are more or less satisfactory. 
When the film is in the form of high speed transparen- 
cies, such as Ektachrome film, it has been found from 
actual experience that dye fading occurs in a relatively 
short period of time regardless of the most sophisticated 
conventional technique for storing the film. 
The dry fading that occurs results in a loss of color 
saturation, a shift in color balance, and a decrease in 
maximum densities recorded on the film. As a cmse- 
quence of dye instability, the value and content of scien- 
tific information contained on the film can be altered 
significantly thus destroying the scientific value of the 
film. Furthermore, fading does not have to proceed to a 
point where images are totally washed out in order for 
damage to be considered undesirable. 
It is therefore an object of the present invention to 
provide a new and improved method of and means for 
archival storage of developed color photographic film 
wherein dye fading, while not completely inhibited, is 
significantly retarded as compared to conventional 
techniques for storing such film. 
DISCLOSURE OF INVENTION 
According to the present invention, dye fading dur- 
ing archival storage of developed color photographic 
film is retarded by placing the film in a sealed, opaque 
vault, introducing a dry, pressurized inert gas into the 
vault while the latter is vented, and sealing the vault 
after the air within the vault has been purged and re- 
placed by the inert gas. Preferably, the gas is nitrogen; 
and the vault is stored at a temperature below room 
temperature to preserve the color photographic emul- 
sions on the film contained within the vault. For short- 
term storage, sodium thiocyanate pads charged with 
water are placed within the vault. For long term stor- 
age, the interior of the vault is kept at a low relative 
humidity. 
BRIEF DESCRIPTION OF DRAWINGS 
An embodiment of the present invention is shown in 
the single FIGURE of drawing which is a perspective 
view, with parts cut away, of a vault for archival stor- 
age,of developed color photographic film according to 
the present invention. 
5 BEST MODE FOR CARRYING OUT THE 
INVENTION 
Referring now to the drawing, reference numeral 10 
designates a vault for archival storage of developed 
color film, the vault comprising an aluminum or non- 
lo corrosive material container 12 to which a cover 14 is 
hinged at 16 to allow developed color film 17 to be 
stored in the container on racks 18 which are spaced 
from the bottom 20 and sides 22 of the container. Cover 
14 fits tightly on the container and a separable fastener 
l5 (not shown) holds the cover securely in place. Gasket 
24, in the form of an O-ring, hermetically seals the 
cover to the container when the fastener is operated. 
Housed within container 12 is a tank 26 containing 
2o dry nitrogen gas to which a perforated gas distribution 
tube 28 is connected by way of valve 30 which has an 
actuator handle 32 extending through a side wall 22 of 
the container. In this way, the valve can be selectively 
opened or closed from the exterior of the container to 
25 control the input of nitrogen gas into the vault. In addi- 
tion, a selectively operable valve 34 is provided in the 
vault, preferably in the cover, for selectively venting 
the vault and controlling the purging of the air in the 
vault. 
Finally, the vault contains a pair of sodium thiocya- 
nate pads 36 charged with water which are utilized for 
the purpose of maintaining a relative humidity in the 
vault in the 40-50% range when relatively short dura- 
tion storage is desired. 
In operation, the developed color photographic film 
in the form of 35 mm, 70 mm, 100 foot rolls, 8" by 10" 
sheets, or other format film, is inserted in the container 
through the open cover. The film rests on the racks 18 
spaced from the bottom and sides of the container. 
40 Generally, the sodium thiocyanate pads will be charged 
with water and the cover 14 closed in order to hermeti- 
cally seal the vault. Handle 32 can then be selectively 
operated for the purpose of introducing dry nitrogen 
gas from tank 26 into the sealed vault. At the same time, 
45 valve 34 is opened in order for the dry nitrogen to purge 
the air within the vault. After the air in the vault is 
purged and replaced by nitrogen at pressure greater 
than mospheric, valve 34 is closed as is valve 30. The 
vault is now charged with pressurized nitrogen and the 
50 developed color photographic film can be stored at 
room temperature. Optionally, the vault is placed in an 
environment which is below room temperature. The 
nitrogen atmosphere effectively prevents oxidation of 
55 the dyes in the emulsions and permits long term storage 
without significant fading of the dyes. 
In the event that relatively long term storage is de- 
sired, the procedure for sealing the developed color 
photographic film in the vault is the same as described 
60 above, except that the sodium thiocyanate pads are not 
utilized. Instead, the film is stored at relatively low 
humidity at a temperature of around 50 degrees F. 
Under these conditions of storage, the vault should be 
allowed to return to room temperature before reopen- 
65 ing; usually one to two days should be allowed for the 
film to return to its condition of 40-5O% relative humid- 
ity before use in order to avoid cracking of the emulsion 
on the film. 
30 
35 
4,287,152 
3 4 
It is believed that the advantages and improved re- 
sults furnished by the method and apparatus of the pres- 
ent invention are apparent from the foregoing descrip- 
tion of the preferred embodiment of the invention. Vari- 
ous changes and modifications may be made without 5 ing to claim 1 wherein the gas is dry nitrogen. 
departing from the spirit scope of the invention as 
described in the claims that follow. 
by inclusion of water-charged pads of sodium thiocya- 
nate therein. 
3. A method for retarding dye fading during archival 
storage of developed color photographic film accord- 
4. A method for retarding dye fading during archival 
storage of developed color photographic film accord- 
ing to claim 3 including the step of storing the vault at 
a temperature below room temperature. 
storage of developed color photographic film accord- 
ing to claim 4 including the step of reopening the vault 
only after its contents have been returned to room tem- 
6. A method for retarding dye fading during archival 
storage of developed color photographic film accord- 
ing to claim 5 including the step Of introducing moisture 
into the vault to return the relative humidity therein to 
We claim: 
1. A method for retarding dye fading during archival 
storage Of “lor photographic film ‘Ompris- lo 5. A method for retarding dye fading during archival ing the steps of: 
(a) placing the film in a sealed opaque vault; 
(b) venting the vault; 
(c) introducing a dry, pressurized inert gas into the 
(d) %ding the vault after fie in the vault is purged 
2. A method for retarding dye fading during archival 
storage of developed color photographic film accord- 
ing to claim 1 wherein the gas is nitrogen and the inte- 20 the range 40-50% before using the film. 
vault while the latter is vented; and 
and replaced by the inert gas. 
15 perature. 
rior of the vault is maintained at a humidity of 6 5 0 %  * * * * *  
25 
30 
35 
40 
45 
50 
55 
60 
65 


Method for retarding dye fading during archival storage of developed color photographic film

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