Estar

I'm currently reading Philip Taubman's "Secret Empire", a history of
strategic reconnaissance of the Soviet Union. The author claims that
Kodak invented Estar film because existing film emulsions would fail in
the rather harsh environment of a (then) super-secret spy satellite.

This is the first I've heard of this particular "spin off". Can anyone
confirm it?
--
Kevin Willoughby lid

It doesn't take many trips in Air Force One
to spoil you. -- Ronald Reagan

kevin willoughby wrote:
I'm currently reading Philip Taubman's "Secret Empire", a history of
strategic reconnaissance of the Soviet Union. The author claims that
Kodak invented Estar film because existing film emulsions would fail in
the rather harsh environment of a (then) super-secret spy satellite.

This is the first I've heard of this particular "spin off". Can anyone
confirm it?

I cannot, but I can say that the military was using Estar-based film
for many years before the Hollywood folks started using it for prints.
High speed cameras were using polyester film in the mid-1960s, with
stocks like Shellburst Linagraph Pan and RAR (Rapid Access and Recording)
2479.

What estar stocks buy you for spy satellite use is the ability to make
very, very thin films. Thin enough that you can cram 250 feet into a
#10 spool intended to hold 100 feet. When you're paying by the pound
to get stuff into orbit and having to snag the recovery canister on
re-entry, anything that gets you more film with less weight is a big
deal.

By the early seventies it was very unusual to find gunsight camera loads
with acetate base, and all of the high speed cameras were using the
stuff because it didn't deform much even at high speeds.

Currently the folks at the National Air and Space Museum have an exhibit
on Project Corona, along with the Defense Mapping Agency guys. It might
be worth sending them an email and asking if they can put you in touch
with some of the DMA historians.

I will look at the back-up of the Lunar Surveyor and see what the film
stock looks like. I'm pretty sure it's estar stuff, probably an RAR
film intended for monobath development. The processing gadget looks
like a sponge and a roller and not much else.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On 2008-11-10 19:04:06 -0800, kevin willoughby
said:

I'm currently reading Philip Taubman's "Secret Empire", a history of
strategic reconnaissance of the Soviet Union. The author claims that
Kodak invented Estar film because existing film emulsions would fail in
the rather harsh environment of a (then) super-secret spy satellite.

This is the first I've heard of this particular "spin off". Can anyone
confirm it?

In addition to providing a thin, very stable base, the spy cameras did
not use silver halide, but used a photosensitive dye for essentially
infinite resolution.

DuPont had a similar base before Kodak.

kevin willoughby wrote:
I'm currently reading Philip Taubman's "Secret Empire", a history of
strategic reconnaissance of the Soviet Union. The author claims that
Kodak invented Estar film because existing film emulsions would fail
in the rather harsh environment of a (then) super-secret spy satellite.

This is the first I've heard of this particular "spin off". Can anyone
confirm it?

That also gets mentioned in Curtis Peebles' book "The Corona Project",
he http://www.geog.ucsb.edu/~kclarke/Corona/story2.htm
....and he http://tinyurl.com/3pb237

Pat

In article ,
lid says...
I'm currently reading Philip Taubman's "Secret Empire", a history of
strategic reconnaissance of the Soviet Union. The author claims that
Kodak invented Estar film because existing film emulsions would fail in
the rather harsh environment of a (then) super-secret spy satellite.

This is the first I've heard of this particular "spin off". Can anyone
confirm it?


Didn't DuPont offer polyester (Mylar) based MP film back in the 1950s?
They did a lot of groundbreaking film development (no pun intended) in
the late 1940s up through the 1950s and I seem to recollect something
about the film base. They sure did some unusual emulsion work.

Marty
--
The American WideScreen Museum
http://www.widescreenmuseum.com/

Peter wrote:

In addition to providing a thin, very stable base, the spy cameras did
not use silver halide, but used a photosensitive dye for essentially
infinite resolution.

This was not always the case. Some of the satellites used diazo emulsions
but the early Corona stuff at least was using silver.

EG&G also sold a film that I think Kodak made for them, which was a
conventional color negative stock, with the same sensitizing dyes used
on each of the three layers. The three layers, though, had very different
speeds.... so you could shoot a frame and then later after the fact use
magenta, yellow, or cyan filters to decide which of the three speed emulsions
gave the best exposure. The end result was much, much wider usable brightness
range.

DuPont had a similar base before Kodak.

I remember that on sheet film. Was it called Cronar or something?
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On 2008-11-11 08:03:52 -0800, (Scott Dorsey) said:

I remember that on sheet film. Was it called Cronar or something?

Cronar, it was indeed.

Early 50s stuff.

--
Peter Haas - Monterey Bay, California - Should you quote, please quote
only the relevant text
It's The Democratic Party®, Bozo, NOT the Democrat party (USPTO Ser.
No. 74152276)

(Scott Dorsey) writes:

EG&G also sold a film that I think Kodak made for them, which was a
conventional color negative stock, with the same sensitizing dyes used
on each of the three layers. The three layers, though, had very different
speeds.... so you could shoot a frame and then later after the fact use
magenta, yellow, or cyan filters to decide which of the three speed emulsions
gave the best exposure. The end result was much, much wider usable brightness
range.

Slight correction: you would use a red, green, or blue filter.

In a normal negative film, the red-sensing layer uses a cyan dye so it
controls the transmission of red light through the negative while
(ideally) having no effect on green and blue, which are controlled by
the green-sensitive (magenta dye) and blue-sensitive (yellow dye)
layers. To see the image in one layer, you would illuminate the film
with one of red, green, or blue light to have just one layer's dye
density contributing to the resulting image.

Dave

Scott Dorsey wrote:
kevin willoughby wrote:
I'm currently reading Philip Taubman's "Secret Empire", a history of
strategic reconnaissance of the Soviet Union. The author claims that
Kodak invented Estar film because existing film emulsions would fail in
the rather harsh environment of a (then) super-secret spy satellite.

What estar stocks buy you for spy satellite use is the ability to make
very, very thin films. Thin enough that you can cram 250 feet into a
#10 spool intended to hold 100 feet.

Long ago, I read somewhere that the Apollo astronauts used Hasselblads
with a special film. "Ektachrome with a special thin film stock". Any
chance it was Estar?


Currently the folks at the National Air and Space Museum have an exhibit
on Project Corona

I may have been too terse in my original post. The (then) super-secret
spy satellite was, indeed, Corona.
--
Kevin Willoughby lid

It doesn't take many trips in Air Force One
to spoil you. -- Ronald Reagan

kevin willoughby wrote:

Long ago, I read somewhere that the Apollo astronauts used Hasselblads
with a special film. "Ektachrome with a special thin film stock". Any
chance it was Estar?

Yes, it was on Estar Thin Base, which was actually very common for that
kind of application. It was standard ME-4 process aerial Ektachrome film
on thin base.

Just about everything that used film in flight was using Estar base by
the late sixties because the stuff was so difficult to damage and so much
lighter. Even gun cameras and radarscope cameras.

Currently the folks at the National Air and Space Museum have an exhibit
on Project Corona

I may have been too terse in my original post. The (then) super-secret
spy satellite was, indeed, Corona.

Go check out the NASM exhibit, they actually have some of the original
films on display. Corona wasn't the only one of the spy satellite systems
but it was a single project that lasted for many years through many different
generations of film technology, which makes it interesting for demonstration
purposes. It's also the project for which the most information has become
declassified, too.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."