Ektachrome history

Ed_Nyari · Jun 27, 2007

Hi there

I bought a nice scientific article by Kodak engineers from 1952.
They studied interimage effects in old Ektachrome type B film.

Now I'm trying to figure out which film was that.
Tungsten from 1952. I'd assume the ASA rating was about 12-16 , but who knows.

So does anyone have any idea of what kind of Ektachrome films there were back then.

I'd settle for a rough estimate of speed, so just shoot the lowest ISO you ever heard for Ektachrome, and what year was it.

The film is sheet film, so it's either original E process or E3.
Since it's 1952. I'd bet it's original Ektachrome process.

I'm kind of currious also, how did these images look like.
Has anyone actually seen such an old corrected Ektachrome image that hasn't faded beyond uncorrectability?

The curves in the article suggest it had a much lower density range
than modern E6, or even Ektachrome 25.
The blacks must have looked a little thin, and judging by the curve, the whites looked pretty dirty too.
What is interesting is that the slope of the straight portion is milder than of modern films, and it has a GIANT toe and sholder, nothing like new films.
So the straight portion is way shorter.

I actually overlayed a modern film curve over this one (stretched the graph to precisely match desnity and exposure scales) and the difference is pretty big.

Photo Engineer · Jun 28, 2007

Sounds like the original Ektachrome film to me. It was out about then.

That was a 75 degree process and the examples I have have faded badly. Several of my slides were used in the new book by Ctein on digital restoration of photographs.

I processed these when I was a teen.

The C-22 negatives from that time are still ok, but the Ektachrome has been gradually turning red. The Ektachrome was grainy and not very sharp. Blacks looked good (at the time). The color was quite nice, accurate but not overdone. The speed was not more than 25, but I cannot remember for sure. I think it was though, because it took less exposure than the Kodachrome that I used at the time which was 10.

PE

Helen B · Jun 28, 2007

I've got plenty of photo mags from the 50's and I'll look through them when I get back. Could you show us the curves from the article?

Thanks,
Helen

Craig · Jun 28, 2007

Photo Engineer said:
the Kodachrome that I used at the time which was 10.

PE

Interestingly Kodachrome at the time in roll film had a speed of 10, while the Professional Kodachrome in sheets was 6.

Ed_Nyari · Jun 28, 2007

Helen B said:
I've got plenty of photo mags from the 50's and I'll look through them when I get back. Could you show us the curves from the article?

Thanks,
Helen

Personally I have no problem with that, but those are not curves from the product sheet that Kodak usually publishes for free, but are actual results from the study (experiment). The study was originally published in a magazine, and is now being soled.
So basically it would be piracy. I don't know what is the policy of this forum about that. I don't want to offend anyone around here.

Helen B · Jun 28, 2007

I'd be happy to buy the article - could you give us the reference?

Thanks,
Helen

Ed_Nyari · Jun 28, 2007

Sure, here it is.
http://www.opticsinfobase.org/abstract.cfm?id=50460

Ed_Nyari · Jun 28, 2007

To give you some clue what it's about before you decide to buy..

It's a short article showing the process through which they tried to come up with equations that will make density of every layer a function of exposure of all 3 layers. In other words they wanted to present interimage effects as a function.
There are a series of tests with combinations of uniform exposures and step-tablet exposures.
The test show how uniforme exposure of one layer is actually twisted by step-tablet exposure of the other layer, showing a negative image, made just through interimage effects without any exposure.
Same is repeated for all layers.
As a byproduct of this test, they came up with a standard characteristics curve for that film too, because they needed it as a reference.

dmr · Jun 28, 2007

Photo Engineer said:
The C-22 negatives from that time are still ok, but the Ektachrome has been gradually turning red. The Ektachrome was grainy and not very sharp.

Ektachrome seems to be inconsistent as to how the slides keep after 30 years or so. I shot a lot of it (I guess this would be Ektachrome-X and the original HS Ektachrome) in the early 70s. A few of them actually survived quite well (below) but quite a few have faded in the magenta direction and some appear to have gotten weaker in general but faded, if in the direction of any color, toward cyan.

These three are fairly recent scans of Ektachromes I did in the early 70s. The two of the bridge and the tracks were on hazy days, and it does show.

http://www.rangefinderforum.com/photopost/showphoto.php?photo=15748
http://www.rangefinderforum.com/photopost/showphoto.php?photo=15793
http://www.nycsubway.org/perl/show?41160

Helen B · Jun 28, 2007

Thanks Ed, I wouldn't want you to incur the wrath of the Optical Society of America just because of my curiosity. I'm a member, so I can get that article at a reduced cost.

I kept many of my early Ektachromes frozen. Here are four examples of High Speed Ektachrome Type B from '73.

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Photo Engineer · Jun 28, 2007

Ed_Nyari said:
Personally I have no problem with that, but those are not curves from the product sheet that Kodak usually publishes for free, but are actual results from the study (experiment). The study was originally published in a magazine, and is now being soled.
So basically it would be piracy. I don't know what is the policy of this forum about that. I don't want to offend anyone around here.

Ed;

A lot of that data on interimage has been published in several textbooks. If you could give the authors names, I could probably find some complimentary data in the texts that I have here.

There is a chapter on this in Mees and James, and also the complete textbooks "An introduction to Color" by Ralph Evans and "Principles of Color Photography" by Evans, Hanson and Brewer. Some of this includes the matrix math for the dyes and there are characteristic curves shown.

The exposures referred to are called "undercut" and "double undercut" exposures. They show how one color can 'undercut' another or how two colors can 'double undercut' another.

Much work on Ektachrome was done by Neuberger and Murray. Work on negatives was done by Bello and Kofron and Zwick.

PE

Ed_Nyari · Jun 28, 2007

Ron

The authors are Hanson jr. and Horton

Helen.
I like the look of those slides you posted. Do you perhaps have some gallery set up somewhere where I could see more of them?
If not, could I get a larger sized version of the second one? I'd like to take a closer look at it.

Photo Engineer · Jun 28, 2007

Ed;

Then with W. T. Hanson as author, you get the author of 2 of the primary textbooks on the subject. The texts will probably go into more detail. Work by the others will be more up to date.

PE

Ed_Nyari · Jun 28, 2007

Can these books be purchased in the same way (as E-books)?

By the way, I actually bought this because it speaks in the context
of early color photography, which is what I'm really interested in: early color films

I'll probably look for more of such texts

Photo Engineer · Jun 28, 2007

Ed;

I really have no idea. I bought these in the 50s as first edition hard cover books. Sorry I can't help there. They are part of a library and I have never given it much thought.

PE

Ed_Nyari · Jun 28, 2007

Can you tell me, which of these two books speaks more about concrete and less about color theory in general. Because I'm really not that interested in general color theory as much as getting to know more about actual characteristics of materials of that time, both negative and reversal.

Do any of these books speak of concrete problems found in materials of that age, and show their sensitometric and colorimetric data?

Photo Engineer · Jun 28, 2007

Neither book has much concrete data of that sort. It is a lot of theory and math with dye curves and matrix algebra.

Most of what you describe was done, but not published. I'll see what I can find.

PE

Photo Engineer · Jun 28, 2007

Example of color undercut exposure

I have had an envelope of these in my darkroom since the 80s. This is an 80s Ektachrome 64 printed onto either Ektaflex R or Radiance paper. I cannot tell which.

The exposure is a series showing the color gamut from red to cyan. To do justice to this, the entire series consisted of neutrals, magenta to green, yellow to blue and etc, and was usually both examined spectrophotographically and densitometrically.

The exposure was made on the film using WR 98,99 and 70 filters with a crossed step chart, and the prints onto the paper were made with corrected white light.

It was also done on negative film. I'll try to post more later. I have one other set.

PE

Photo Engineer · Jun 28, 2007

After reading this over, I think it needs clarification. The experiment consists of 3 parts.

1. Expose film to WR 98, 99 and 70 filters to make the original grid. This shows what the film can do all on its own.

2. Expose the paper to the same grid with the same filters to show what the paper does on its own.

3. Expose the film results from #1 onto the paper with white light to show what the SYSTEM is capable of.

Optional extras include real photos shot alongside and printed alongside these with a reference color checker in the scene, and also with resolution charts.

This is part of the design stage of Ektachrome Film and Ektachrome Paper.

PE

Ed_Nyari · Jun 28, 2007

Seems like some serious red blocking up.

Thanks, this is really interesting. How precise is the scan?

Photo Engineer · Jun 28, 2007

The scan is fair. The blocking is partly an artifact of being exposed so as to insure a complete sensitometric scale is reproduced and some extra.

However, this is pos-pos and that is typically subject to blocking anyhow as I have repeatedly said.

PE

Photo Engineer · Jun 28, 2007

I might also point out that this was an experiment run nearly 25 years ago and just sitting around in an envelope in my darkroom. IDK what it even consisted of except that it demonstrates the general methodology of testing for you.

So, please don't judge it or anything else I post as representative as it may not even have been any sort of a product. I merely had a sample sheet in my DR.

PE

Ed_Nyari · Jun 29, 2007

Ok, thanks

@Helen:

Did you read my post a few posts back (the question about your slides)?
If you missed, it could you please go back?

thanks

Helen B · Jun 29, 2007

Hi Ed,

I've seen it now. I can send you a much larger version, just PM me with an email address and maximum file size or a postal addres for a CD of the original file. I have more Ektachromes from the late 60s and early 70s, including the daylight ASA 64 version, and some were kept frozen as those four were. I'll dig the files out. Some were scanned at 8000 ppi at 16 bits on an Imacon.

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Best,
Helen

Ed_Nyari · Jun 29, 2007

Helen, I've sent you a PM.

And thanks, really looking forward to seeing more of these old slides if you find any

Ektachrome history

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