Pulling Slide Film

Henning;

You say how you tested it, but not how it was measured! You obviously cannot measure reversal and negative films by the same method! You can't measure prints either for similar reasons.

So, how did you measure it?

PE

Photo Engineer said:

So, how did you measure it?

PE

Click to expand...

Hello Ron,

we've used the industry standard method, which is used for decades (e.g. by all lens manufacturers like Zeiss, Leica, Schneider etc.) for analysing system resolution (film + lens).
The resolution charts were analysed under a microscope with 40x and 100x enlargement. Under a microscope you really see what the film has captured. It's the most precise method. Usable for negative film and positve film, BW and colour.
We've discussed our methods and results with Dr. H. Nasse, chief optic designer of Zeiss, and got confirmation.

Furthermore we analysed the whole imaging chain: Optical enlarging with APO-lenses, scanning with drum scanners (Imacon X5 and ICG 370) and Nikon Coolscan 5000 scanner, and projection with different high quality projecting lenses.
Very short summary of the results:
Highest system resolution in the whole imaging chain is achieved with optical enlarging and projection. Loss in resolution compared to the results under the microscope in only 5 - 10%.
Same with slide projection. Getting 120 lp/mm on the projection screen with e.g Velvia 100 is possible with high quality projection lens
[the current digital beamers (the most expensive 7000 - 10000€ class) with their extremely low resolution of max. 2 MP deliver 15 - 20 lp/mm on the screen.
Slide projection is the field where quality advantages of film compared to digital technique is really huge].
With drum scanners the reduction in resolution is bigger, 20 - 40% dependent on the film.
Far behind is 4000 ppi scanning with the Coolscan 5000 (effective 3600 ppi). Worst resolution values of all, significant loss in detail. 70 lp/mm is the limit, more is not possible, even with high resolution films or higher object contrast.
Scanners are limited by the Nyquist frequency. An optical imaging chain (lenses + film) is not, here the limiting factors are diffraction and object contrast.
As resolution is dependant on object contrast, the differences are bigger with higher object contrast (more than our 1:4), and they decrease with less object contrast.

Best regards,
Henning

Well, the method you used is excellent and just fine for comparing 2 optical trains with 1 film, or one train with 2 or more slide films with identical contrasts, but in this case you are comparing a slide film with a contrast of about 1.8 and a negative film with a contrast of about 0.6, so how do you normalize the results?

And, even though you get a difference, how do you explain the data presented by Kodak and others which says that the Ektar is sharper than the Ektachrome?

I have personally done lab tests (minus optics) which give negative films the lead when the contrast differences are ironed out. Also, and in any case, given identical optics the degree of degradation should be comparable between the films. Thus the Kodak data should stand on its own merit.

PE

I recently popped a contrast-increase mask on a 6x7 Ektar neg and enlarged it to 20x24 for testing purposes. That's nothing I plan to do routinely because the overall results are still quite inferior to the
what I get with larger sheet film. But it was a real eye-opener in terms of grain, and the now apparent
fact that the limiting factor with Ektar is going to be lens resolution and plane of focus, not grain magnification or film resolution per se. And yes, all other things being equal, it is distinctly sharper than any Ektachrome film at a comparable level of print contrast.

Hi Ron,

Photo Engineer said:

Well, the method you used is excellent and just fine for comparing 2 optical trains with 1 film, or one train with 2 or more slide films with identical contrasts, but in this case you are comparing a slide film with a contrast of about 1.8 and a negative film with a contrast of about 0.6, so how do you normalize the results?

Click to expand...

all BW films were developed to the same contrast.

Colour films: All slide films were developed in standard E6 process, professional lab (Kodak Q-Lab).
All CN films in standard C-41, the same professional lab.

The reasons for this workflow:
1. Normalizing of the overall, global contrast would make no sense, because we want results relevant for real, daily photography, real pictures, and not for pure lab comparisons.
In daily photography no photographer would increase the contrast of his color negs from 0.6 to to 1.8, and no photographer would decrease the contrast of his slide film down to 0.6. The films are not designed for this 'abuse'.
Negative film works best with the lower contrast, and slide film with its higher contrast, that's why it is used in that way. Including all pros and cons.
If you now change the contrast dramatically you would loose the strengts of films in both cases, and you would gain nothing.

And our interest was to see the results the films deliver when they are used in the way all photographers use it.
When you print optically you have the differences between neg and positive film, and when you scan as well (of course also when you project it, but that makes seldom sense with negatives; nevertheless we've done it with high resolution films with extremely interesting results, but that is another story).
That is what we are doing in our daily photography, and are confronted with the (different) results.
To analyse these results was our interest.

In general you have the higher global contrast with slide film, and of course resolution benefits from that. That is an essential characteristic of slide film.
But you have to pay for it with less dynamic range because of the higher contrast.
And the other way round with negative film. Less resolution, but higher d.r..
There is no free lunch.

2. Global contrast is not the major factor for resolution of higher spatial frequencies. Here microcontrast is important, the contrast of the extremely fine black and white lines. And the difference in microcontrast between slide film and negative film at these high spatial frequencies is much much lower than the global contrast. You even see this clearly with the eye under the microscope, and you get that confirmed with densitometric tests (what we did).

Photo Engineer said:

And, even though you get a difference, how do you explain the data presented by Kodak and others which says that the Ektar is sharper than the Ektachrome?

Click to expand...

I guess you refer to the MTF chart, and not to Kodaks marketing statement.....

Our experience with doing such tests for more than 20 years now is that MTF data has very little relevance for real life shooting under normal photography conditions. MTF data is generated under completely different conditions, e.g. with much higher object contrast.
Our contrast is lower, because most details in scenes have low(er) object contrast. And our interest is daily photography.
And with lower object contrast slide film performs better.
And there are differences in MTF data from manufacturer to manufacturer (different test conditions).
For example we have made the experience that the MTF data of Fuji is quite conservative. It is relatively easy to reach their resolution values.
A friend of mine, using the same method, but only with littler higher contrast (1:8) and a different lens has even achieved slightly higher resolution with Pro 160C than Fuji data gives for 1:1000 contrast.
These differences between MTF data and test results with real shots (higher as expected resolution in real shooting conditions) was also confirmed by Zeiss.

Therefore the result from our experience: If you want to see the real resolution, sharpness, grain, dynamic range, than take photographs with your equipment, your lenses, your films, your needed object contrast etc.
MTF data is not the answer of your questions concerning your equipment and your individual shooting conditions. Look at your pictures, not at curves from someone else.

Best regards,
Henning

Well, Henning, you are right in theory but the best way to compare (which is at the current time really impossible) is to compare the slide to a transparency prepared on print film from the negative, or go to the absolute measurements as posted by Kodak.

The bottom line is that you cannot, at this time, make a valid comparison of the two film systems. But, I think that the comments by Drew Wiley above point out what is actually being observed by many and that is that the neg-pos system is superior in spite of the extra step between the picture and the viewer.

As I said, back when I ran tests in the lab the C41 films were as good as or better than E6 films and at that time I had Ektachrome Paper (Radiance etc..) to compare with Supra or whatever negative paper I used. This, along with modeling and actual direct tests gave a pretty good "picture" of which was best.

PE

Hi Ron,

sorry to say, but I have to disagree.

Photo Engineer said:

Well, Henning, you are right in theory

Click to expand...

No, the other way round. Your proposition of normalising contrast is a theoretical concept working maybe in lab conditions, but not in real life photography.
It may be of academic interest, but has no relevance for photographers, because no one would do this with his slide or negative films.
No photographer is dramatically increasing the contrast of his negative films, or dramatically decreasing the contrast of his slide films, because this would lead to a significant loss in picture quality in both cases.

In the vast majority of the cases photographers use the C-41 and E6 process in the standard way.
So therefore they are interested in the results they get this way.
I've never heard of a photographer who increases the contrast of his color negs to 1.2 or 1.8, or a photographer who decreases the contrast of his slides down to 1.2 or 0.6.
For tests and comparisons, which should be useful and relevant for daily photography, you have to use the processes in the way they are really used by photographers.

Photo Engineer said:

but the best way to compare (which is at the current time really impossible) is to compare the slide to a transparency prepared on print film from the negative,

Click to expand...

No one is doing this.
Slides are either projected (best resolution you cant get), viewed on a light table with loupe or directly printed (Ilfochrome; Harman Direct Positive paper for BW slides), or scanned and then printed on RA-4.
Negatives are either printed directly with optical printing or scanned and printed.

That are the ways photographers work. That is our photographers reality.
So therefore we should analyse the results we get with the processes we really use.
And that is what we've done:
With optical printing slides (Ilfochrome, H.D.P.) with APO enlarging lenses the resolution of ISO 100 color slides films surpasses the resolution of optical printed Reala, Ektar, Farbwelt 100 (German version of Gold 100).
Same with drum scanned slides vs. drum scanned negatives. As already mentioned, the overall resolution was less, and the difference was smaller as well.

Photo Engineer said:

or go to the absolute measurements as posted by Kodak.

Click to expand...

They are generated under lab conditions. With higher contrast ratios which are quite seldom in normal photography.
Using significantly lower object contrast (as we did) gives a much better, more valid picture of what can really be achieved in daily photography.

Photo Engineer said:

The bottom line is that you cannot, at this time, make a valid comparison of the two film systems.

Click to expand...

Well, yes and no.
Of course yo can compare the results of the processes photographers really use (see above).
Photographers want to know about the possibilities and limitations of their materials and processes.
Nothing wrong with having a look at this.

But of course right is as well that both films systems are designed for different purposes. Slide for projection and light table view, negative for prints.
Therefore no surprise that they shine with overall best results (considering all relevant parameters, not only resolution and sharpness) in the area they are designed for.

Well, that is the reason I use both systems. Horses for courses.
I've never understood this "slide vs. negative film fight" some photographers (interestingly most of them pure C-41 shooters) are in.
There is no "best" system in general. Only the best solution for a certain application.

But, as a reminder, the start of the discussion here was Athirils statement that Portra 400 new has higher resolution than Provia 400X.
And at least due to our test results with an object contrast of 1:4 Provia 400X delivers higher resolution values. That is the result looking directly on the films with a microscope, making optical prints and with drum scans.

Photo Engineer said:

As I said, back when I ran tests in the lab the C41 films were as good as or better than E6 films and at that time I had Ektachrome Paper (Radiance etc..) to compare with Supra or whatever negative paper I used.
PE

Click to expand...

Well, you retired in 1997, right? The films and papers you used are not on the market anymore. We've tested the current products
(I can say lots of progress in film technology during the last 20 years, if I compare the current films with the ones form the early 90s).
And you said you have normalised the object contrast of the two film systems. A method photographers don't work with.

Best regards,
Henning

Henning;

I refer you to "A review of the old and n ew methods of evaluating the image structure of color films" by M. Kriss published in the notes of the SPSE "Color: Theory and Imaging Systems" in 1972. This is an excellent reference for this topic.

And, I might remind you that there have been few advances put into E6 products since the mid '90s but color negative film has continued to advance! Ektar compared to any Ektachrome film is at least 2 -3 generations ahead in technology.

PE

And, I might remind you that there have been few advances put into E6 products since the mid '90s but color negative film has continued to advance! Ektar compared to any Ektachrome film is at least 2 -3 generations ahead in technology.

Amen. I'd waste no more energy arguing with Henning if he's unwilling or unable to grasp this. E6 really is a dead material relative to current C41.

CGW said:

E6 really is a dead material relative to current C41.

Click to expand...

A sad reminder of what is happening in the slide film world.

I have always wanted to shoot 120 slide film and buy a projector for it--I understand the projected quality is awesome and the huge images mesmerizing--but never got around to it. I could still do it but it is a little late in the game to get started. Who knows when it will all disappear.

Mostly it was when a Professional shooter screwed up a calculation and said oh damn.
I asked for pull processing once or twice usually because I thought the studio images were over exposed by a half stop. The results were never optimal.
I pushed on purpose as a photojournalist many times... I shot Ektachrome 100, 400 and 1600 sometimes pushed 2 stops back in the day. Blacks would get greenish casts... it would get put on a drum scanner and published same day.

RPC said:

A sad reminder of what is happening in the slide film world.

I have always wanted to shoot 120 slide film and buy a projector for it--I understand the projected quality is awesome and the huge images mesmerizing--but never got around to it. I could still do it but it is a little late in the game to get started. Who knows when it will all disappear.

Click to expand...

If you can then do it. All I meant was that quality E6 processing became the constraint--why bother when a lab screwed up simply because of stale chemistry caused by low volume? I'm still shooting it simply because I can still access good processing and have pals with Cabin and Kindermann projectors and big screens.

I do miss Scala film desperately, though.

RPC said:

A sad reminder of what is happening in the slide film world.

I have always wanted to shoot 120 slide film and buy a projector for it--I understand the projected quality is awesome and the huge images mesmerizing--but never got around to it. I could still do it but it is a little late in the game to get started. Who knows when it will all disappear.

Click to expand...

If I were you, I'd skip the projector for now (unless one falls in your lap at a good price) and start burning the film. The images are big enough to look at and ooh and aah over, they scan well if that's your thing, and the eventual "it will all disappear" moment should just mean that you can get the projector for a song.

I held off shooting E-6 at all for a number of years, out of an exaggerated fear of its difficulty, and I very much regret the shots I didn't get as a result. IMHO, enjoy it while it's there to enjoy.

-NT

Even after encountering it many times, I am still astounded when I hear people put down slide film. All I can say is that I have been shooting film since the dawn of the digital age, yet still remember the thrill of getting my first box of slides back. The incredible colors, clarity, brilliance, and resolution. A roll of Elite Chrome 200, shot in my dads old Minolta XG-7, with a 50mm lens, looikng out over the Chicago skyline from the top of the Hancock Center. Wow, people, n a row boat, maybe 1/2 mile away, and the oars clearly visible! I had never experienced this with negative film before.
Since then I have discovered that slides scan better and more easily than negs too: better colors with less need for tweaking to get rght, sharper, with less grain allowing for easer sharpening without the need for blurring filters, and better resolution. Yet still you hear the crazy talk on the Net, the Urban Legend that slde is more difficult to scan. The exact opposite is true!
Photo Engineer, I respect you greatly, and dont want to offend you, but when I read your comments about Ektar being 2-3 generations ahead of slide, I thought to myself, yes, but 2-3 generations behind slide in results. I have tried to love it too, but been let down too many times when my slide shots came out great, and the Ektar paled in comparison. The one exception being sunsets, where it equals slide film results for impact and beauty.

CGW said:

E6 really is a dead material relative to current C41.

Click to expand...

It definitely has not been developed to the degree of modern C-41 films, which are amazing.

But...I still like the way E-6 looks and I like working with it...as I always have. I will do so as long as it is around. I view E-6's role in my life as such: If I have grown up using my No. 2 pencils, and they have always done what I require/expect of them, I don't stop using them just because a technically superior pencil core is developed. I don't go around proclaiming the technical superiority of the No. 2 pencil over the new stuff, but I also don't stop using them in favor of it.

So, I wouldn't say it is quite dead, but rather that is has been left behind to die by film manufacturers. And as sad as it is to me, it makes sense. Why spend tons money developing high-tech new products for which there is almost no market? Even I, a big proponent of keeping E-6 alive, probably shoot 25 percent or less of what I used to shoot on E-6....and as mentioned, I don't even think the things I do shoot on E-6 would benefit from the films being any "better."

pukalo said:

Even after encountering it many times, I am still astounded when I hear people put down slide film. All I can say is that I have been shooting film since the dawn of the digital age, yet still remember the thrill of getting my first box of slides back. The incredible colors, clarity, brilliance, and resolution. A roll of Elite Chrome 200, shot in my dads old Minolta XG-7, with a 50mm lens, looikng out over the Chicago skyline from the top of the Hancock Center. Wow, people, n a row boat, maybe 1/2 mile away, and the oars clearly visible! I had never experienced this with negative film before.
Since then I have discovered that slides scan better and more easily than negs too: better colors with less need for tweaking to get rght, sharper, with less grain allowing for easer sharpening without the need for blurring filters, and better resolution. Yet still you hear the crazy talk on the Net, the Urban Legend that slde is more difficult to scan. The exact opposite is true!
Photo Engineer, I respect you greatly, and dont want to offend you, but when I read your comments about Ektar being 2-3 generations ahead of slide, I thought to myself, yes, but 2-3 generations behind slide in results. I have tried to love it too, but been let down too many times when my slide shots came out great, and the Ektar paled in comparison. The one exception being sunsets, where it equals slide film results for impact and beauty.

Click to expand...

The people who design scanners have little understanding of negative films. A true expert can get more out of a negative than a slide. And, R&D on slide films is considerably less advanced than that of negative film due to the market.

PE

Dear Ron,

I am very sorry for my very late reply, but I have struggled with a severe illness for a very long time.

Photo Engineer said:

Henning;

I refer you to "A review of the old and n ew methods of evaluating the image structure of color films" by M. Kriss published in the notes of the SPSE "Color: Theory and Imaging Systems" in 1972. This is an excellent reference for this topic.

Click to expand...

Thanks, I will try to get it.
Published in 1972, almost 40 years ago, even before E6 (and C-41, if I rember right) were introduced.
Well, as I have mentioned above, the main interest of our detailed test programme are the films which are currently on the market.

Photo Engineer said:

And, I might remind you that there have been few advances put into E6 products since the mid '90s but color negative film has continued to advance!

Click to expand...

I agree with you concerning Kodak and Agfa, but have to disagree concerning Fuji. Fuji has made quite big steps and progress in E6 film technology during the last twenty years. They surpassed Kodak at the beginning of the '90s.
The 'Panther' film line of Kodak at that time was weak compared to Fuji films and was not accepted by the market. Fuji became market leader in slide films.
Even in the last 8 years there has been significant progress in Fuji slide films. Astia 100F, Sensia 100 (III), Velvia 100F, Velvia 100 and as the latest, only 4 years back Provia 400X. All were significantly improved compared to the former versions.
Provia 400X for example has fineness of grain and resolution on a level comparable to some ISO 100 films. E100VS / Elitechrome ExtraColor 100 deliver only a bit better detail, the difference is there but not big (the last Agfa RSX 100 was even worse than 400X). Color rendition of 400X is excellent and on the same level as ISO 100 films.
If you compare Provia 400X to the last Ektachrome 400X, well this difference is really huge. No chance at all for the Ektachrome 400X.

Kodak reached Fuji's level again in 2003 at least with their new Ektachrome E100G, E100GX and Elitechrome 100. Excellent films with comparable performance to Fuji's 100 ISO films.

Photo Engineer said:

Ektar compared to any Ektachrome film is at least 2 -3 generations ahead in technology.
PE

Click to expand...

Our test results are very clear about the comparison of Ektar 100 to E100G and Elitechrome 100:

Resolution and sharpness of both slide films are much superior to Ektar 100:
Resolution with object contrast of 1:4:
E100G and Elitechrome 100: 120 - 135 Lp/mm
Ektar 100: 90 - 105 Lp/mm

Grain is a little bit finer with the Ektachromes (if you are interested I can send you some test shots, originals).

Kodak introduced Ektar 100 first only as 35mm film, and in its amateur line. And said it is optmised for scanning. It was adressed for a certain market segment.
I talked at Photokina 2008, when Ektar 100 was introduced, to the Kodak people and they told me that. Also they said there will be no Ektar 100 120 or sheet film (well, they later changed their mind).
And that is indeed what they really did: A film optimised for the most widespread amateur scanners with max. resolution of 4000 ppi.
Most of these scanners get real 3600 ppi (Nikon Coolscan 5000 e.g.), that is about 70 Lp/mm resolution.
Kodak sacrificed a bit resolution (Gold 100 has indeed about 15% higher resolution, but significantly coarser grain compared to Ektar) to get finer grain, because with these 4000 ppi scanners grain is the most visible problem (often enhanced by scanner noise).
Ektar 100 is a product specifically designed for this certain market segment, and it fits very well in this application.
But from a technological point of view and the test results, E100G, Elitechrome 100 and all ISO 100 Fuji slide films deliver better detail rendition. Visible directly on the film (see my postings above) and with drum scanners.
And when you compare a projected slide to a Ektar print of the same size.

Best regards,
Henning

Henning;

Sorry to hear about your illness. I hope that you are back up to par.

Try here: http://www.kodak.com/global/en/professional/support/techPubs/e4024/e4024.pdf page 6

and here: http://www.kodak.com/global/en/professional/support/techPubs/e4046/e4046.pdf page 5

You see the response of the Ektachrome falling off at 20 c/mm falling below 100 whereas the Ektar remains at about 100 at this same point. The projected red response at 100 c/mm is not very good.

I again stress that contrast can confound measurements.

PE

Photo Engineer said:

Henning;

Sorry to hear about your illness. I hope that you are back up to par.

Click to expand...

Thanks Ron, not quite yet, but it is getting better.

Photo Engineer said:

Try here: http://www.kodak.com/global/en/professional/support/techPubs/e4024/e4024.pdf page 6

and here: http://www.kodak.com/global/en/professional/support/techPubs/e4046/e4046.pdf page 5

You see the response of the Ektachrome falling off at 20 c/mm falling below 100 whereas the Ektar remains at about 100 at this same point. The projected red response at 100 c/mm is not very good.

Click to expand...

Well, of course we know the data from the tech. pubs. very well.

And that is one result of our work in testing films, sensors and lenses for more than 20 years now:
The technical data published by the manufacturers is of limited informative value for real life photography, because the laboratory test methods have some significant differences compared to normal shooting conditions photographers use in their normal daily photography.

That is why we use test methods which are closely related to normal photography: Normal cameras and lenses, tripods and lower object contrast (1:4; not 1:1000).

We've found that this is not an Kodak related issue, but true for all manufacturers. Sometimes the data from the data sheets leads to too high expectations (we've experienced this especially with some Agfa films in the past), but sometimes the official data is even a bit too conservative (example: some Fuji CN films).

So from this experience (we probably have the biggest private test archiv worldwide with over 5000 test results) our recommendation is:
Test your films by shooting it under the conditions they are used by the photographer.

Photo Engineer said:

I again stress that contrast can confound measurements.

PE

Click to expand...

Of course, that's right.
That is one reason why we measure the object contrast of the test subject by two different methods before a test is started.
And we always say at which object contrast our tests were done.
Sharpness and resolution are dependant on object contrast. Lot's of people don't consider this.

Best regards,
Henning

Do it to lower contrast. I used to do it for direct printing to Cibachrome. If I used uncoated lenses, results were even better. The slides looked like something for the bin, but printed on Ciba perfectly.

Time was cut in first developer only, the rest of the 6 or 8 steps remained the same.