Journal of Film Preservation - FIAF

y different processing techniques, and have sustained different forms of
use and storage, and therefore cannot be subjected to a single ‘universal’
method of color restoration. Our research indicates that all of the
Chinese-processed copies of the same kind of Agfa color cine positive
have roughly the same relatively high color stability and slow fading rate,
and thus color restoration of these prints is easily accomplished. Film
processed with the former Soviet [HNKON] technology manifest nearly
100% fading in the cyan layer within a short period of time. Our color
restoration process has not obtained appreciable results in the case of
these films.
4. Color Restoration of Eastman 5381 Oil-soluble Color Prints
In the mid-1970s, it was noted that film prints from a Chinese
laboratory using Eastman 5381 color print film showed serious fading in
the magenta color layer within a relatively short time. The loss of the
yellow-green color range at levels approximating 50% were quite
common, along with loss of density. To address this problem, a process
of color restoration using the technique of oxidation-reduction was
developed by a Shanghai laboratory, using immersion in an iodinepotassium
iodide oxidation solution, a wash, and then immersion in a
sodium sulphide solution. The method is outlined in Table 2:
Restorating Technology
Table 2: Restorating Technology
Proceeding Temperature Time
Iodine-potassium iodide 24±0.5°C 3 min
Water-wash 21–24°C 15 sec
Sodium sulfide 24°C 2 min
Water-wash 21–24°C 4 min
Formaldehyde stability solution 24°C 15 sec
Note:
(1) The print to be processed is not pre-washed in water; the film should be dry
when immersed in the iodine-potassium iodide solution.
(2) The water-wash step between the first solution (iodine-potassium iodide) and
the second solution (sodium sulphide) must be strictly controlled (less than
15 seconds); otherwise, this stage produces a failure of the dye restoration.
(3) The iodine-potassium iodide must be completely dissolved in solution; all
sediment must be filtered.
(4) The treatment can be repeated if the density and magenta values are not
satisfactory after the first pass.
(5) Care must be taken to maintain the purity of the sodium sulphide and
formaldehyde solution; contaminants in this phase of the process have a
tendency to adhere to the surface of the emulsion layer.
43 Journal of Film Preservation / 58/59 / 1999
Color image restored with oxidative singlebath
technology (comparison before and after
restoration) (cine film “Kim Ok-hi”)
Restauración de películas en colores
La degradación, generlizada y rápida, de la
imagen de películas en colores se ha
transformado en un impotante motivo de
preocupación. Fabricantes de películas,
exhibidores y conservadores coinciden en
concentrar esfuerzos para mejorar la
estabilidad de las imágenes en colores. Los
fabricantes aportan mejoras a los
procediamentos químicos de duplicación y
revelado con el objeto de retardar el proceso
de degradación, los expertos de la
conservación mejoran permanentemente las
condiciones de almacenamiento y
preservación de películas. Numerosos
métodos han sido adaptados para corregir
los colores al nivel del copiado. Todos ellos
implican procedimentos tecnológicos
complejos y costosos. A partir de los años
70, los autoros de este artículo han
desarollado una serie de procedimientos de
restauración de los colores. Se trata, según
ellos, de un tratamiento químico destinado a
atenuar o intensificar de manera directa y
selectiva las sombras de imágenes
subsistentes, de manera a recuperar los
colores perdidos y restablecer el equilibrio
entre los colores originales. Los inventores
del método esperan obtener los mejores
resultados de este procediento que estiman
corresponder a criterios de rapidez, costos,
seguridad y fiabilidad óptimos.