Update on Original Kodachrome Speed!
cin...@hotmail.com
Magazine
on page 396:
Kodachrome Speed
There have been two important changes in Kodachrome Film made during
the past
few weeks.These changes are called to your attention so that you will
immediately
know the correct course to follow with regard to the use of this
particular film.
Change No. 1
As supplied to the market during the last six months, Kodachrome Film
required
a Weston speed of 4 Scheine 15. This film speed and the original
developing
process gave satisfactory results on cameras that were correctly
calibrated.
A new development process has recently been introduced which changes
the speed
of the original emulsion from a Weston speed of 4-15 Scheine to a
Weston speed
of 6-17 Scheine.
All of the above speeds referred to are for Daylight. No information
is available at the
moment regarding Tungsten light.
Note that the above change was a change to the development process and
not a
change due to a change in the film itself.
Change No. 2
Within the last few days a new Kodachrome emulsion Film has been
introduced on
the market. This new emulsion, when developed by the new process,
increases the
speed of this film from the original value of 4 Scheine 15 to a new
value of approx-
imately 10 Scheine 19. This value is tentative and subject to revision
when further
tests are completed. These values are for Daylight, again there being
no data
available at the moment for Tungsten.
The new emulsion can be identified by noting the emulsion number.
Numbers above
"9120" indicate the new emulsion, which require the higher Weston
speed.
Number "9120" and below are old emulsion numbers and require a Weston
speed
of 6 Scheine 17 if developed by the new process.
Also in the February 1937 SMPE Journal on page 173 there is an article
"Medical Motion
Pictures in Color" which was presented at the Fall meeting at
Rochester N.Y. (12th-15th
October 1936). This article is mainly concerned with the use of the
new Type A Kodachrome
for producing medical motion pictures.
After the paper was presented by Mr. R.P. Schwartz from the University
of Rochester School
of Medicine and Mr. H. B. Tuttle from Eastman Kodak. At the end of the
paper a 16mm film was
presented that was filmed on the type "A" Kodachrome. After the film
was shown there was a
discussion and Mr. Tuttle stated the following:
"When making the picture, the field was illuminated with one medical
spotlamp,and exposures
were made with an aperture of f/4, on the artificial-light type of
film that has been available for
the past few months. Within the past week or so, new fast artificial-
light film has been placed
upon the market that is twice as fast as the old film, so that the
same scene can be filmed today
at f/5.6 with one medical spotlight equipped with a 500-watt, 100-105
volt lamp."
It would appear then, the original speed of both Daylight balanced
Kodachrome and Type "A"
Kodachrome was effectively doubled in Sept-October 1936, two years
before the change to to the
Selective Exposure process in October 1938.
Regards,
Peter Mason
cin...@hotmail.com
> of Rochester School
> of Medicine and Mr. H. B. Tuttle from Eastman Kodak. At the end of the
> paper a 16mm film was
> presented that was filmed on the type "A" Kodachrome. After the film
> was shown there was a
> discussion and Mr. Tuttle stated the following:
>
> "When making the picture, the field was illuminated with one medical
> spotlamp,and exposures
> were made with an aperture of f/4, on the artificial-light type of
> film that has been available for
> the past few months. Within the past week or so, new fast artificial-
> light film has been placed
> upon the market that is twice as fast as the old film, so that the
> same scene can be filmed today
> at f/5.6 with one medical spotlight equipped with a 500-watt, 100-105
> volt lamp."
>
> It would appear then, the original speed of both Daylight balanced
> Kodachrome and Type "A"
> Kodachrome was effectively doubled in Sept-October 1936, two years
> before the change to to the
> Selective Exposure process in October 1938.
>
> Regards,
> Peter Mason
The found the following in the August 1936 American Cinematographer on
page 350:
Film Speeds
It is worth while picking up the new Weston Film Speeds sheet at your
dealer
if you use a Weston meter. The latest sheet is dated June 1936.
Considerable
space is given to Kodachrome film. It rates this film at 4 for daylight
(with or without filter)
and 1.5 for photoflood with filter.It gives 8mm the same rating.
Special note is made about
Kodachrome A and gives it a rating for tungsten or photoflood the same
as regular
Kodachrome for daylight. In other words it rates it 4 for interior
lighting.
It rates for still film as well as movie film and also gives rating
for positive film
when used in the camera.
Information I have from August 1938 indicates the speed for Type A
Kodachrme
was Weston 12, equivalent to 16ASA.
Kodachrome Type A was originally introduced in April 1936(in 16mm) so
within
6 months the speed had tripled from Weston 4 to Weston 12.
Most surprising!
Regards,
Peter Mason
cinemad
> I found the following in the September 1936 American Cinematographer
> Magazine
> on page 396:
>
>
> Kodachrome Speed
>
> There have been two important changes in Kodachrome Film made during
> the past
> few weeks.These changes are called to your attention so that you will
> immediately
> know the correct course to follow with regard to the use of this
> particular film.