"ASA" of 3-strip Technicolor
David Mullen
Technicolor was when it was introduced, when the "faster" version came out
when "Gone with the Wind" was shot, and then what the final working ASA
might have been when they switched from filters to dichroic coatings on the
prism?
For example, Plus-X (80 ASA) and Super-XX (160 ASA) were both released
around the time of GWTW -- would either of these been the panchromatic
element used in the camera? Was Pan-X (40 ASA???) used before 1938 for the
panchromatic elements? And what was the ASA of the orthochromatic element
for the blue record? How much was the light loss of the filters used (red
and green)?
This subject comes up now & then but I have still yet to see a definitive
answer, yet it seems to me that this question should just be settled once
and for all. It MUST be possible to find out what the sensitivities were of
the Kodak b&w stocks in the camera and the filter factor of the red coating
and the green filter.
All I can find is Arthur Miller's comment about 1,000 footcandles being
required to shoot interiors for "The Bluebird" (1940) and how he talked them
down to 500 to 800 footcandles to reduce the amount of light that Shirley
Temple would be subjected to. At f/2.8, 1,000 fc would suggest something
around 10 ASA I think. But that seems low for the "faster" 3-strip process
post-1938.
David Mullen
David Mullen
effective speed for the green record?
Let's say, for example, that Super-XX was the basis for the jump in speed in
1938, if Pan-X had been used before that point for the panchromatic
record -- a jump of two stops in sensitivity.
If the prism split the incoming light 50/50, thus losing a stop in both
directions, and then the green filter cut another 2 stops of light, could we
assume that in 1938, using Super-XX (160 ASA) for the green record , there
was a total of 3 stops light lost in the system before the green record
could get recorded, dropping the effective ASA from 160 ASA to 20 ASA? And
that before 1938, if Pan-X was used instead (40 ASA), that meant an
effective ASA of 5 ASA for the green record?
And what did the switch from a green filter to dichroic coatings (if I
understand this correctly) gain in sensitivity? Another stop -- i.e. from
20 ASA to 40 ASA?
David Mullen
Jim Millick
David Mullen <dav...@earthlink.net> wrote:
>Has anyone got any detailed information of what the effective ASA of 3-strip
>Technicolor was
In a casual conversation I had with DP Allen Daviau, he
mentioned an ASA of 3 for THE WIZARD OF OZ. I'll have to
ask him where he got that number.
Jim
Early Film
David,
I would think the limiting factor on speed would be the pan emulsion behind the
bipack roll in the three strip camera, not the green record. The green only
had a green filter and the prism to absorb the light.
To get to the cyan printer negative (red record) the light would have to pass:
1) Thru the prism. I seem to remember reading somewhere that the sputtered(sp)
gold or later silver coating between the prisms absorbed slightly over one stop
of light.
2) Then there was the magenta filter. I do not know its number or absorption
factor.
3 )Then there was the orange overcoat stock, which was dyed the equivalent of a
23A filter.
Then, finally the red record pan stock!
There was a lot of light loss in the process.
Anybody know the speed of either Rainbow or Eastman bipack color stock?
Since that was the basic stock that was used in the early days, that would be a
good starting point at guessing the speed.
Earl.
Early Film
>Anybody know the speed of either Rainbow or Eastman bipack color stock?
>
>Since that was the basic stock that was used in the early days, that would be
>a good starting point at guessing the speed.
I cannot find my old American Cinematographer Hand Book, but was able to locate
my newer one by Jackson Rose, which was published in 1950.
In 1950, the WESTON speed of both DuPont and Eastman Bipack color stock was
normally rated at 8 daylight and 6 Mazda.
OK, now who can translate Weston to ASA / ISO?
Gee, I cannot remember when I last heard tungsten called Mazda. . . . . . .
Earl.
MitchGross
>mentioned an ASA of 3 for THE WIZARD OF OZ. I'll have to
>ask him where he got that number.
>
And I recall being told ASA 4.
Mitch
Martin Hart
dav...@earthlink.net says...
<SNIP>
> All I can find is Arthur Miller's comment about 1,000 footcandles being
> required to shoot interiors for "The Bluebird" (1940) and how he talked them
> down to 500 to 800 footcandles to reduce the amount of light that Shirley
> Temple would be subjected to. At f/2.8, 1,000 fc would suggest something
> around 10 ASA I think. But that seems low for the "faster" 3-strip process
> post-1938.
All my material is packed up for a temporary move but I distinctly recall
that pre-GWTW film speed was approx ASA 5. GWTW used the new faster stock
rated at ASA 10. I don't recall if that was for tungsten or daylight. I
think it was the daylight speed.
Slow as that might seem, Kodachrome and early Eastman, Ansco, etc. stocks
were in the same ball park over ten years later.
Marty
--
The American WideScreen Museum
www.widescreenmuseum.com
David Joachim
>From: Martin Hart martinha...@BLOCKERwidescreenmuseum.com
>Date: 10/27/01 10:20 PM Central Standard Time
>Message-id: <MPG.164539601...@news-server.houston.rr.com>
Lee Garmes mentioned something about needing 800 foot candles for an f 2.8 at a
70s SMPTE conference. It should be noted that he was saying a lot at that
conference that was questionable (he seemed dulled by age and other infirmities
and would be dead within a year). Other info I have read indicates a semi
consensus that GWTW-era Technicolor was roughly ASA 5. But, who the hell really
knows?
David Joachim
Richard May
the first time any new elements were made outside of either
Technicolor or MGM, Pete Comandini said the speed was about 12.
I'd guess Marty's calculations for the 1939 to mid 1940s are about
right.
DM
Peter
>>
When working with YCM Labs on GONE WITH THE WIND in 1988, which was the first
time any new elements were made outside of either Technicolor or MGM, Pete
Comandini said the speed was about 12.
>>
And the late, great Pete Comandini should know. Believe him.
Clive Tobin
From: "Early Film" <earl...@aol.comedy>
> OK, now who can translate Weston to ASA / ISO?
Seems to me Weston 8 would be ASA 10.
Clive Tobin
at acer-access dot com
http://www.tobincinemasystems.com
Peter
>>
Seems to me Weston 8 would be ASA 10.
>>
10 is competitive with Kodachrome/Commercial Koda/Tech Monopack.
David Mullen
Let's say it was 10 or 12 ASA for the 1938 period -- what was it before
1938? Plus-X and Super-XX were both released in that year -- Plus-X was the
most commonly used stock for b&w features and was one stop faster than the
previous stocks used, according to various interviews. But Super-XX was
another stop faster -- so did 3-strip Technicolor benefit from a one or a
two stop increase in speed in 1938? Basically, was it 5 ASA before 1938 or
even slower?
And once the filters were replaced by dielectric coatings in the late
1940's, what was the effective increase in speed? Could it have doubled to
20 ASA?
Was 16 ASA chosen for the first Eastmancolor negative (daylight-balanced) in
1949 to reflect current speeds used in Technicolor photography? And wasn't
3-strip Technicolor a tungsten-balanced format by then?
David Mullen
Martin Hart
rpm...@aol.com says...
Unfortunately my entire collection of American Cinematographers, all
seven tons of them, are in storage at this moment. Some years ago a
rather well researched article appeared on the subject of MGM's excellent
"Northwest Passage", starring Spencer Tracy and Robert Young. Some
mention was made of the effective film speed. Unfortunately I don't
recall if the picture was made with the original slow or newer "fast"
stock. There was apparently not a sharp cutoff between the slow and
faster stocks. GWTW was purported to be the first film to use the faster
material but some films released later supposedly were shot on the slow
version.
Steve Kraus
> Gee, I cannot remember when I last heard tungsten called Mazda. . . . . . .
Mazda is the deity of goodness and light in Zoroastrianism and (I think)
was a GE trademark for light bulbs.
David Mullen
>seven tons of them, are in storage at this moment. Some years ago a
>rather well researched article appeared on the subject of MGM's excellent
>"Northwest Passage", starring Spencer Tracy and Robert Young. Some
>mention was made of the effective film speed. Unfortunately I don't
>recall if the picture was made with the original slow or newer "fast"
>stock.
From "American Cinematographer", article on "Northwest Passage", Nov. 1987:
Since the second unit material had been shot in 1938, Technicolor had
introduced a new, much faster film with some modified characteristics. The
first feature film to be shot in the revised process was "Gone With The
Wind", which commenced principal photography in January, 1939. Ray Rennahan
said in the August 1939 issue of "American Cinematographer" that "the new
film is three times as fast as the old film under artificial light, and four
times as fast in daylight... [and yields] improved color rendition,
particularly in the greens. Every color process has found green one of the
hardest colors to reproduce faithfully... The new film, with its
finer-grained characteristics, also gives us considerably better
definition."
____
So no mention of an actual speed, but I'm assuming that since the process
was still daylight-balanced back then that the only reason it would be
slower under artificial light (which if carbon arcs were used, it should
have been the same as shooting in daylight) is if correction filters were
necessary on the camera for filming under tungsten maybe. I don't know, it
just seems odd otherwise that the speed would be different for real daylight
versus artificial daylight using carbon arcs.
Anyway, "four times faster" suggests a two-stop increase, so if it were 12
ASA for the new version, then it would have been 3 ASA before.
I'm not sure, however, how Kodak could make a new stock in 1938 that was two
stops faster for Technicolor yet have "finer-grained characteristics" with
"better definition". It would seem to me that the ability to stop down the
lens a little rather than shoot wide-open, plus the advent of
anti-reflection coating on lenses, would have been the main reason for
improved definition. But I can't figure out how the grain could get reduced
but the speed increased four times. Maybe it had improved red sensitivity
(the grainiest record) which kept the red record from getting too
underexposed.
David Mullen
Peter
>>
10 is competitive with Kodachrome/Commercial Koda/Tech Monopack.
>>
Further thought ...
Technicolor's Three-Strip of 10, which is competitive with those single-film
processes mentioned above, gives you incredibly better quality, and an
end-to-end process flow as well.
So, it really isn't just about the ASA of the principal photography materials,
but about the suitability of the entire process.
Monopack utilized most of the Technicolor process, but the taking of an
inferior reversal original (muddy shadow details, e.g.) and the making of seps
from that orginal, compromized the remainder of the process.
Plus, the reality is Three-Strip remained a "no risk" process until it was
discontinued in 1955, while Eastman remained a risky process until good, stable
camera stocks and good, high resolution intermediate materials were finally
available, perhaps about ten years later.
It took a little than that for Eastman to come out with good positive printe
materials (LPP).
Peter
>>
And once the filters were replaced by dielectric coatings ...
>>
Dichroic
Dielectric is an electrical property of an insulator.
Peter
>>
... Every color process has found green one of the
hardest colors to reproduce faithfully ...
>>
A significant consideration as the green record was the source of the K record
(used for edge detail enhancement), and was also the source of the workprint,
for Three-Strip.
David Mullen
>>>
>
>Dichroic
>
>Dielectric is an electrical property of an insulator.
I was just quoting that term from Haine's book on Technicolor (pg. 23), so I
guess he used the wrong word.
David Mullen
Peter
>>
Mazda is the deity of goodness and light in Zoroastrianism and (I think) was a
GE trademark for light bulbs.
>>
Mazda may have been a General Electric acquisition.
The trademark is also used outside the U.S., perhaps where General Electric
Company Limited (not in any way related to U.S.'s General Electric Company) is
active.
David Mullen
correspond to Arthur Miller's mention that he used 800 to 1000 footcandles
for shooting "Little Princess" around that time, assuming shooting at around
f/2.8, which was common for 3-strip photography on stages.
If Rennahan is correct that the 1938 process was "four times faster" (two
stops) than the 1934-1938 version of 3-strip Technicolor, then that makes
the previous version something more like 3 ASA or even below that slightly.
Let's just say, 3 ASA for the 1934-1938 version and 12 ASA for the 1938 to
late 1940's version.
So what happened to the sensitivity when the mirror coatings were changed
from gold to silver, or did that just change the color balance? And what
happened to the sensitivity when dichroic coatings replaced the green and
magenta filters on the ends of the prism block? Could the process have
reached an effective 25 or 32 ASA rating by the end (1955)?
David Mullen
Stephen Furley
> And once the filters were replaced by dielectric coatings in the late
> 1940's, what was the effective increase in speed? Could it have doubled to
> 20 ASA?
Did you mean dichroic?
Stephen Furley
A couple of years ago Jack Cardif came to a screening of "the Red
Shoes", I should know the date but can't remember at the moment, and
"The Great Mr. Handel", 1942, at a small cinema in London. I spoke to
him after the show about Handel, and the figure of 12 is also close to
what he said.
Peter Mason
According to American Cinematographer magazines from the mid thirties
Super X
was the panchromatic film used before the change was made to the
higher speed
product in 1939.(Actually there is evidence to suggest that the first
film
to use the higher speed product was THE WIZARD OF OZ and not GWTW as
is widely
claimed.) The speed of Super X was 32 Weston(40ASA) and when the new
product was
introduced it is highly likely that the new film used for the
panchromatic
record was Plus X or something very similar. If you look at the SMPE
Journal
for I think 1939(Progress Report May 1939 edition I think) it mentions
the fact that the improvements made to the B/W stocks were
instrumental in increasing the speed of the new TECHNICOLOR stock.
With the change to the newer film the
magenta and green filters were eliminated and the green filter was
replaced with
a yellow filter(since orthochromatic film was now being used for the
green
record) and the magenta filter was eliminated completely since the new
Bi-pack
film was made up of a blue only sensitive front film with a orange/red
filter
layer behind it and the panchromatic film behind that.(Probably Plus
X)
When the change was made in the early 50's to the tungsten balance the
beam-
splitter prism and filter was replaced with dichroic filters to
separate the
light and this effectively doubled the speed to 16 WESTON(20ASA)
of the former TECHNICOLOR process.
REGARDS
Peter Mason
David Mullen
>eliminated and the green filter was replaced with a yellow filter
>(since orthochromatic film was now being used for the green
>record) and the magenta filter was eliminated completely since the
>new Bi-pack film was made up of a blue only sensitive front film with a
>orange/red filter layer behind it and the panchromatic film behind that
Even with an othrochromatic film (to record the blue record) that was
red-orange dyed to remove blue wavelengths and record the red record on the
panchromatic stock behind it, wouldn't the magenta filter still be necessary
in order to cancel any green wavelengths? Or was there enough magenta color
in the dyed ortho element to cancel green?
If the orthochromatic stock had ANY green sensitivity, it would need the
magenta filter in front of it in order to not record green information as
well as blue. And if it DIDN'T have any green sensitivity, then how could
the green record be recorded onto othrochromatic stock as well instead of
using panchromatic stock?
Are you saying that the blue record was made onto a blue-only sensitive
orthochromatic stock but the green record was (after 1938) was made onto a
DIFFERENT blue-green sensitive orthochromatic stock with a yellow filter to
cancel the blue information?
Also, does anyone know what developments allowed Kodak to increase the speed
of their black & white stocks so much in 1938?
And again, if we're talking about a 10 to 12 ASA rating for the post-1938
version of 3-strip, and maybe a 3 ASA before 1938... how much faster did it
get in the last few years of existence (1950-55)? Up to 25 ASA?
David Mullen
Martin Hart
peter...@aol.communicate says...
I fully agree that green reproduction has always been the least faithful
to real life, but I don't think that shortcomings in that record would
have had a serious impact on the silver key image or work prints. The
key image for "Becky Sharp" was the blue record. The characteristics of
the blue and green records are so vastly different that it would seem
almost impossible to use blue as the key unless it was printed very, very
faintly. In practice, the green record produced an image that was nearly
panchromatic in appearance, except that foliage was a tad lighter than it
should be.
In playing around with color separations, I've always felt that the green
record was THE critical one when it comes to perceived sharpness and
overall gamma of the image. The red and blue records can be downright
mushy looking but if the green is good the overall appearance will be
relatively good. I'm probably all wet on that, but that's what my own
work seems to indicate.
Martin Hart
screenBL...@filmteknik.com says...
I believe that the Mazda trademark was applied to light bulbs using the
conventional threaded base that is common to household lighting. I've
run across many old G-E ads for Mazda lights, and they were plain old
ordinary light bulbs. The really big screw based lamps are Moguls.
David Mullen
>record was THE critical one when it comes to perceived sharpness and
>overall gamma of the image. The red and blue records can be downright
>mushy looking but if the green is good the overall appearance will be
>relatively good. I'm probably all wet on that, but that's what my own
>work seems to indicate.
It's interesting to note that in digital video cameras, the green channel
carries most of the luminence information as well as its color, while the
red and blue channels are more compressed (one possible reason why
greenscreens are preferred to bluescreens by some people doing digital
composite work -- also because the blue layer of filmstocks used are
grainier than the other layers). In many ways, the 3 CCD camcorder is the
direct descendant of the 3-strip Technicolor camera.
David Mullen
Peter
>>
... The key image for "Becky Sharp" was the blue record ...
>>
That was a mistake, and was a deviation from the process.
Peter
>>
In many ways, the 3 CCD camcorder is the direct descendant of the 3-strip
Technicolor camera.
>>
The early color cameras used individual dichroic mirrors. Two of them in a
"Vee" configuration, with additional, first-surface relay mirrors so that the
camera tubes would be colinear.
Later, Plumbicon cameras would use a prism, much as the Three-Strip camera did,
and the camera tubes would not be colinear, much as the Three-Strip was not
colinear, but they would be oriented 90 degrees to each other, as on the
Three-Strip.
Finally, a unique prism was implemented in which the camera tubes were splayed
about 30 degrees, but were coplanar.
Each one of these developments included such advantages as reduction of
air-to-glass surfaces and/or sealed surfaces, with the final incarnation being
one totally sealed optical block.
Scott Dorsey
>
>I cannot find my old American Cinematographer Hand Book, but was able to locate
>my newer one by Jackson Rose, which was published in 1950.
>
>In 1950, the WESTON speed of both DuPont and Eastman Bipack color stock was
>normally rated at 8 daylight and 6 Mazda.
>
>OK, now who can translate Weston to ASA / ISO?
The Weston rating process eventually became the ASA method, although with
a couple of changes so that most films rate a little bit higher on the
standardized ASA scale than on the Weston scale. A Weston 8 film is somewhere
between 8 and 12 ASA depending on the shape of the curve.
The ISO method measures a bunch of points along the curve, and it is more
accurate for describing the speeds of highly compensating films like modern
color negative stocks. For example, the modern Kodak Gold 200 would be
considered something like 320 ASA by the old method because it does not take
into account the amount of overexposure possible before the highlights
become crushed.
>Gee, I cannot remember when I last heard tungsten called Mazda. . . . . . .
When did you last see films marked for different speeds when used with
white and yellow flame arcs?
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Peter
>>
I believe that the Mazda trademark was applied to light bulbs using the
conventional threaded base that is common to household lighting. I've run
across many old G-E ads for Mazda lights, and they were plain old ordinary
light bulbs. The really big screw based lamps are Moguls.
>>
The conventional base bulbs are also called Edison base or medium base.
C2001
Perhaps this explains why it's so much easier to manipulate green than
red or blue (or yellow), using the 'color effect' tool in the Avid
Xpress Image Palette.
You can reduce or strengthen the green signal with considerable
flexibility, but even one or two plus or minus adjustments to blue or
red can generate total loss of chroma subtlety. Sometimes reducing the
_overall_ chroma signal is the most effective way to get rid of
oversaturated chroma in video.
Tiffen now has an NLE filter package, but at present it's only available
for NT and not Mac.
Charles
JohnW248
Mullen" <dav...@earthlink.net> writes:
> Ray Rennahan
>said in the August 1939 issue of "American Cinematographer" that "the new
>film is three times as fast as the old film under artificial light, and four
>times as fast in daylight... [and yields] improved color rendition,
>particularly in the greens.
The problem with assigning an ASA to any of the Technicolor 3-strip processes
is that the whole process was internal to Technicolor. To get an accurate ASA,
one has to expose the film to a know source and read the H&D curve. Since
Technicolor controlled processing and printing, the only feedback a DP got was
his "Cinex" strip which reflected his "printing light' for the previous day's
work.
And in the case of Technicolor, they had there own "lights" and one cannot
assign or correlate B&H D printer lights (1-22) to the Technicolor lights. The
B&H lights are log lights light f/stops and the Tech lights (I believe if I can
remember accurately) were much narrower in their range fewer in number.
Since the whole process was internal to the lab, the feedback to the DP was
used to provide them (the lab) with an exposure they wanted to work with. All
of the observations I've heard are based on set lighting foot candles and the
Technicolor exposure to yield an acceptable print. I have also heard the 6-12
ASA from both DP's and former Technicolor workers.
John
Peter Mason
> >With the change to the newer film the magenta and green filters were
> >eliminated and the green filter was replaced with a yellow filter
> >(since orthochromatic film was now being used for the green
> >record) and the magenta filter was eliminated completely since the
> >new Bi-pack film was made up of a blue only sensitive front film with a
> >orange/red filter layer behind it and the panchromatic film behind that
>
> Even with an othrochromatic film (to record the blue record) that was
> red-orange dyed to remove blue wavelengths and record the red record on the
> panchromatic stock behind it, wouldn't the magenta filter still be necessary
> in order to cancel any green wavelengths? Or was there enough magenta color
> in the dyed ortho element to cancel green?
>
> If the orthochromatic stock had ANY green sensitivity, it would need the
> magenta filter in front of it in order to not record green information as
> well as blue. And if it DIDN'T have any green sensitivity, then how could
> the green record be recorded onto othrochromatic stock as well instead of
> using panchromatic stock?
The front film in the bi-pack was purely blue sensitive, it had no
green
sensitivity, and behind it was placed an orange red filter layer which
absorbed
cyan(ie blue and green), from 1939 the panchromatic film that was up
to that time used to record the green record was replaced with an
ortho-
chromatic film(sensitive to blue and green), the green filter was
replaced with
a yellow filter which absorbed blue only and allowed the green colors
to pass
and record onto the orthochromatic film only the green colors. The
yellow filter
allowed a lot more light to pass than the green filter.
>
> Are you saying that the blue record was made onto a blue-only sensitive
> orthochromatic stock but the green record was (after 1938) was made onto a
> DIFFERENT blue-green sensitive orthochromatic stock with a yellow filter to
> cancel the blue information?
>
The blue record was made on a purely blue sensitive stock. It was not
ortho-
chromatic since ortho stocks are both blue and green sensitive. The
separate green record was made onto a separate orthochromatic stock
with the yellow
filter. A lot of people doubt this information when I tell them
because just about every bit of published information refers to the
green and magenta filters
and they refuse to believe that they were done away with in 1939 but I
ASSURE
you this is the case.
> Also, does anyone know what developments allowed Kodak to increase the speed
> of their black & white stocks so much in 1938?
>
If you check the Progress Committee report in the May 1939(I think?)
SMPE
Journal or somewhere in that edition you may find this information?
> And again, if we're talking about a 10 to 12 ASA rating for the post-1938
> version of 3-strip, and maybe a 3 ASA before 1938... how much faster did it
> get in the last few years of existence (1950-55)? Up to 25 ASA?
>
When the change was made to a tungsten balance in 1951 the speed was
doubled
to 16 WESTON, this increase in speed was brought about through the use
of the dichroic prism which divided the light from the camera lens
into the 3 colours
and the light losses associated with the beam splitter and yellow
filter were
eliminated. I'm pretty certain that the speed remained at 16 WESTON
until
the last American TECHNICOLOR film FOXFIRE was released in 1955. I
understand
the last British TECHNICOLOR( 3-strip) release was THE FEMININE TOUCH
the
following year.
It would seem to me that when the change was made to using the
Dichroic
prism in 1951 that the configuration of the Bi-packs would have to be
changed.
If you had the blue sensitive and the red sensitive film bi-packed as
in
the original system and those colors are at the opposite end of the
spectrum
how could the Dichroic prism make both those colors available to the
same
film aperture? This is purely speculation but could they have changed
the bi-pack so that the blue and green records ran together and placed
a yellow filter
layer behind the blue record to prevent any blue light reaching the
back
orthochromatic green record film. Could the Dichroic prism separate
the light
from the camera lens into CYAN(for the blue and green sensitive
bi-pack) and
orange red for the now separately running panchromatic red record?
As I said this is purely SPECULATION!
REGARDS
Peter Mason
Martin Hart
dav...@earthlink.net says...
>
> It's interesting to note that in digital video cameras, the green channel
> carries most of the luminence information as well as its color, while the
> red and blue channels are more compressed (one possible reason why
> greenscreens are preferred to bluescreens by some people doing digital
> composite work -- also because the blue layer of filmstocks used are
> grainier than the other layers). In many ways, the 3 CCD camcorder is the
> direct descendant of the 3-strip Technicolor camera.
>
> David Mullen
The importance of green and much lesser importance of blue seems to carry
into other aspects of digital imaging. Often times I come across a
digital photo (JPG with lossy compression) that I want to use but which
is not quite up to the quality level I like, I do whatever I can to clean
the image up. When I split the picture into the primary color channels
invariably the blue channel is nearly a patchwork looking thing with
little detail. Even the high res scans I do show inferior representation
of the blue record in many instances.
Martin Hart
peter...@aol.communicate says...
>
> >>
> ... The key image for "Becky Sharp" was the blue record ...
> >>
>
> That was a mistake, and was a deviation from the process.
>
It may have been a mistake. But I have no information that it was not
intentional. It damned sure came as a surprise to the restorers of the
film. "Becky Sharp" was the first feature length three strip film and
it's possible that there was some reason for using the blue element as
the key, but it really escapes me as to what it might have been.
Steve Kraus
> The ISO method measures a bunch of points along the curve, and it is more
> accurate for describing the speeds of highly compensating films like modern
> color negative stocks. For example, the modern Kodak Gold 200 would be
> considered something like 320 ASA by the old method because it does not take
> into account the amount of overexposure possible before the highlights
> become crushed.
I thought the ISO rating was simply the ASA number and the DIN number.
Morgan Montague
"Peter" <peter...@aol.communicate> wrote in message
news:20011029024031...@mb-mv.aol.com...
Let's not forget some of those Maxfield Parish (sp?) paintings for MAZDA
David Mullen
>> version of 3-strip, and maybe a 3 ASA before 1938... how much faster did
it
>> get in the last few years of existence (1950-55)? Up to 25 ASA?
>
>When the change was made to a tungsten balance in 1951 the speed was
>doubled
>to 16 WESTON,
What's the equivalent ASA rating for 16 WESTON?
If 3-strip Technicolor became around 10 to 12 ASA in 1938, and the speed was
doubled, are we talking about 20 to 25 ASA for the 1951-1955 period?
David Mullen
Jan-Eric Nystrom
> I believe that the Mazda trademark was applied to light bulbs using the
> conventional threaded base that is common to household lighting. I've
> run across many old G-E ads for Mazda lights, and they were plain old
> ordinary light bulbs. The really big screw based lamps are Moguls.
I always thought Mazda was a car - I drive one myself... ;-)
Seriously: I have an old Ektachrome slide from 1956 (shot by my father)
that unintentionally includes a pack of flashbulbs; a green-and yellow
box with large white letters "MAZDA".
I also have a 12 V, 35 watt, H1 or H3 auto-type socket (keep forgetting
which is which) halogen bulb in my French-made 16mm movie wiever, and
the lamp's base is imprinted with the Mazda label...
--
regards, /////
/ - - \
Jan-Eric Nystrom, animator (--@-@--)
Helsinki, Finland \ _o_ /
E-mail: ani...@sci.fi \_*_/
---------------------------------oOOo---oOOo-----
Animation Web page: http://www.sci.fi/~animato
Model Engineering & Live Steam Locomotive webpage:
http://members.surfeu.fi/animato/steamloco.html
Scott Dorsey
The ISO method is a little different than the earlier ASA method in the way
they measure the speed. They will give you identical results with typical
B&W emulsions, but the ISO speed will be a little bit lower on compensating
films.
It's not a huge difference and as always, the real film speed varies with
processing conditions.
The DIN method is not only a little bit different than the ASA method but
they use a logarithmic scale rather than a linear one. They just pick
different points than the ASA method does, but the results are pretty close
once you convert scales.
Eric Grayson
wrote:
>David Mullen wrote:
>>
>> >In playing around with color separations, I've always felt that the
green
>> >record was THE critical one when it comes to perceived sharpness and
>> >overall gamma of the image. The red and blue records can be downright
>> >mushy looking but if the green is good the overall appearance will be
>> >relatively good. I'm probably all wet on that, but that's what my own
>> >work seems to indicate.
>>
If you're really anal about color clarity and image sharpness (like I am),
one of the things you can try is to do multiple scans of each image and
then average them together in a program like Photoshop. The shadow detail
will increase tremendously and the grainy qualities you see will minimize.
If you look at a histogram of the red, green, and blue channels, you'll
often notice that the red and blue channels simply have fewer bits of color
in them. I find that doing four scans increases the clarity.
I started doing this back in the dark ages when we only had a black and
white scanner and I had to scan things with three filters. CCD technology
likes green the same way that film likes blue. It's nearly blind to red.
This has changed a little through the years but is still fundamentally
true.
Eric
Clive Tobin
> What's the equivalent ASA rating for 16 WESTON?
20 more or less.
--
Clive Tobin
at acer-access dot com
http://www.tobincinemasystems.com
Peter Mason
> >> And again, if we're talking about a 10 to 12 ASA rating for the post-1938
> >> version of 3-strip, and maybe a 3 ASA before 1938... how much faster did
> it
> >> get in the last few years of existence (1950-55)? Up to 25 ASA?
> >
> >When the change was made to a tungsten balance in 1951 the speed was
> >doubled
> >to 16 WESTON,
>
> What's the equivalent ASA rating for 16 WESTON?
>
> If 3-strip Technicolor became around 10 to 12 ASA in 1938, and the speed was
> doubled, are we talking about 20 to 25 ASA for the 1951-1955 period?
>
The mathemathics is you multiply the WESTON speed by 1.25 and that gives you the
ASA speed.Thus 16 WESTON is equal to 20 ASA, which was TECHNICOLOR's speed
between 1951 to 1955.
REGARDS
Peter Mason