PhotoStudio13 discontinuing Scala process

I am very curious.
You can collect some trash pieces from different films and then send them to me.
Kind regards
Klaus

Thank you - I'm bookmarking this thread and when I'll gather my samples, I'll PM you for details - have a great one!

Klaus Wehner said:

to #69, #70

I have mentioned the "effective density".

But it is the "gross density". So I measured the silver density and the veil density together.
To know the "net density" you have to subtract the veil density (0.15...0.25) from the gross density.

Best regards
Klaus

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What I was attempting to ask was whether your process is designed to deliver absolute maximum Dmax/ density range - or for optimal tone curve/ speed (with a high enough Dmax to give a satisfactory 'black' and very clean highlights).

to #78

Only achieving the highest possible density is pointless. What would that be good for?

My process is optimized for slide projection on a screen in the best possible quality.
To achieve a good black (zone 0) on the screen under good projection conditions, you need a slide with a maximum density oft about 4.00.

Everyone can try this out at home with their own projector: at what density can the projector no longer screen the slide?

All densities smaller than 4.00 result in the gray scales from deep black to pure white. For a film with a harmonic and linear gradation curve, you get corresponding harmonic gray values in the slide.
The density interval between black and white is about 3.80. For a paper image (reflected light), the density difference between black and white is about 2.00.
For this reason, a projected slide can represent all gray levels in a much more differentiated way than any other medium.

Best regards
Klaus

Klaus: if it's possible, can you kindly share the HD-curve for FP4+ (or any film that gives DMax of -4) when reversed in your process? That will be of immense pedagogical value to some of us.

The last development of a FP-4 I made on 14.07.2021.

The sensitometry clip had the following gross densities:
Zone VII.5: 0.35
Zone V: 1.12
Zone II,5: 3,46
D.max: 4.10

I hope that this information is sufficient.

Kind regards
Klaus

Klaus Wehner said:

The last development of a FP-4 I made on 14.07.2021.

The sensitometry clip had the following gross densities:
Zone VII.5: 0.35
Zone V: 1.12
Zone II,5: 3,46
D.max: 4.10

I hope that this information is sufficient.

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This is most useful! Thank you!

I've very (very!) roughly plotted the data provided & then superimposed the curve (in red) on to Velvia 50, E100 and Scala 200x's published characteristic curves (all scaled to match each other as closely as possible). The good news is that the highlights seem to track quite well with Velvia 50 and E100 (which both have remarkably similar characteristic curve shapes - at least in the sector that matters for tonal reproduction) - I'm not so sure about the gradient of the straight-line section or the transitions at the shadow end. A bit of fiddling around with the Wehner FP4+ curve suggests that a slightly lower Dmax and a sharpened shadow/ straight line transition could net a longer, less steep straight line, much closer to that of an E-6 film.

Thank you! That is a very interesting comparison.

A black and white slide usually needs a higher contrast than a color slide.

Example: a red apple hanging in a green apple tree can be seen without problems in a color slide even without a high brightness contrast.
In a black-and-white slide, however, the contrast must be as high as possible so that the apple is clearly visible in the green foliage. Here, only the brightness contrast can work. This should be high enough to make as many details as possible clearly visible.

The three curves show well how a higher contrast contributes to a better differentiation of the gray levels.
A brilliant slide will be able to show more details than a low-contrast slide.

Best regards
Klaus

dmtnkl said:

I contacted them and got a reply today. They are going to shut down the whole company. It's not just about the Scala service after all.

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They stopped because the owner is old and retiring. The service will be continued by the established professional lab "Prolab Fotofachlabor GmbH" in Stuttgart, Germany. Some Photo Studio 13 employees will continue working at Prolab. The owner of Prolab is a former Photo Studio 13 employee, he got his education there.
As Prolab is already fully established and equipped for years, they will continue with their own dip-and-dunk film processing machines. But there is no place for the Scala dip-and-dunk processing machine. That is the main reason why the Scala operation is not transferred to Prolab.

Best regards,
Henning

Hello Lachlan,

Lachlan Young said:

I think it used a re-exposure reversal step and never went to chemical reversal.

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That is correct. The original Agfa Scala process which was used by Photo Studio 13 used a second exposure, and not chemical reversal like in E6 process.

Lachlan Young said:

Thus you would need a fairly specifically designed processor - likely not a million miles off how the K-14 machines worked, or Agfa's old reversal process (which didn't go to chemical reversal either as far as I know) will have required.

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That is not correct. The process is far away from the complexity of K-14. Photo Studio 13 used a modified Refrema E6 dip-and-dunk processing machine. I was there, and have seen it in operation.

Best regards,
Henning

Hello Klaus,

Klaus Wehner said:

This is also a good way to roughly estimate the maximum density:
Hold the black slide directly in front of your eye and then look into a light source (desk lamp) for about 30...60 seconds.
At a density of about 3.00 you can just see the light source but not the surrounding area.

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I can confirm this. This "rule of thumb" works relatively well.
And what can also be seen this way:
You can only see through the transparency (slide) if you have it directly in front of your eye. The greater the distance to the transparency, the denser and deeper the black looks, and it is then impossible to look through it.
The light intensity is decreasing disproportionately high with increasing distance ("Abstandsgesetz", distance law, I ~ 1/r²). And that is also one of the reasons why a Dmax of 3 on a transparency is enough for having real blacks on the screen, viewed at normal viewing distances. You are not looking at the projected picture on the screen from just some centimeters, but from normally 3-5 meters distance in a standard living room.

Klaus Wehner said:

My process is optimized for slide projection on a screen in the best possible quality.
To achieve a good black (zone 0) on the screen under good projection conditions, you need a slide with a maximum density oft about 4.00.

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Well, that is your personal preference, but not a general physical requirement.
Therefore I have partly to disagree here with you, as such a high Dmax is not always necessary to have real, deep, textureless blacks on the screen with normal viewing distances. Concerning light intensity and brillance I am using the best transparency projection technology which is available: A 250W Leica Pradovit PC with the improved condensor system (20% more light), and as screen the Da-Lite with HP surface, which is the most brillant surface possible, delivering outstanding projection quality.
And I have a four-digit number of BW transparencies here with Dmax values in the range of 2.8 - 3.3 (dependent on the film), which all deliver sufficient deep blacks in the projection on HP screen.
There is a simple rule here: If you have a real black in the original subject, you also get it on screen with normal viewing distances. Physics, the distance law / Abstandsgesetz is working here to our benefit.
And none of my viewers of my BW transparencies from that Dmax group has ever complained about the blacks. Just the opposite, all were impressed.
Having a higher Dmax is of course nice (like those I have from your and another process), but it is not an absolute necessity to have that. Otherwise Agfa Scala and the Foma process would not have had so much satisfied users over all the years.
From my experience with diferrent BW transparency films and different processes I recommend an a bit more relaxed attitude concerning Dmax. It should not be a "fetish", as the overall quality of a transparency is determined by several factors, and not only by one.
And Klaus, an extremely high Dmax is worthless if the slides are yellowing over the time......you know what I mean .

Best regards,
Henning

Henning Serger said:

And Klaus, an extremely high Dmax is worthless if the slides are yellowing over the time......you know what I mean

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Henning,
I'm not Klaus, but in my experiments with black & white reversal processing so far, I have always fixed the film after the re-development step; I take it this is what you're referring to?
Tom

Tom Kershaw said:

Henning,
I'm not Klaus, but in my experiments with black & white reversal processing so far, I have always fixed the film after the re-development step; I take it this is what you're referring to?
Tom

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Yes, a final fix is always necessary, as there can be "defunct", undeveloped silver-halide crystals in the emulsion (it is described in the original Agfa Scala technical documentation for the prof. Scala labs) even after the re-development step. They have to be removed by fix.

Best regards,
Henning

Henning Serger said:

an extremely high Dmax is worthless if the slides are yellowing over the time

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Dye fading? But that would be a possibility only if dye was used to get the rich blacks as in some kind of dye-based intensification.

Raghu Kuvempunagar said:

Dye fading?

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No, as the affected films had no dyes.

Best regards,
Henning

Henning Serger said:

And that is also one of the reasons why a Dmax of 3 on a transparency is enough for having real blacks on the screen, viewed at normal viewing distances. You are not looking at the projected picture on the screen from just some centimeters, but from normally 3-5 meters distance in a standard living room.

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Interestingly, "Basic Photographic Materials and Processes" says this on DMax of reversal films:
"Although these films are capable of achieving densities above 3.0, the shadows are best reproduced at densities 2.7 and less depending on the contrast of the negative."

I vaguely recollect reading elsewhere that this is due to flare on the projection surface.

The book I mentioned earlier has this to say on the highlights:
"Experience indicates that the minimum useful point on the film positive curve for useful highlight reproduction is approximately 0.3 above the density of the fog. If the highlights are reproduced with a greater density than this, they appear too dark, and if the density is any less, they look "washed out"."

I tried to replicate (and translate) the B&W reversal process method I used in my Colenta.
As the original document I made dated from 2005, I couldn't open it with my more recent computer/software...
So, this spreadsheet is made based on my hand written notes, but my hand writing wasn't the 'cleanest', and still isn't.
I haven't processed B&W reversal for the last 7 years, and due to a T.I.A., things have changed a little...
(I stopped E-6 only a few years ago)

yes, it is true that the conditions have a great influence during projection.

Details such as the quality of the slide frames, the refraction properties of the screen, stray light in the room, brightness of the projection lamp, quality of the projection lens, size of the projected image.... have an influence on the result.

I don't know the mentioned book, but I suppose that it is a bit older.
Probably the statements apply primarily to color slides. Black and white slides have somewhat different requirements.

Under good conditions, a density of 3.00...3.50 can be used well for zone II.5.

Best regards
Klaus

Philippe-Georges said:

I tried to replicate (and translate) the B&W reversal process method I used in my Colenta.
As the original document I made dated from 2005, I couldn't open it with my more recent computer/software...
So, this spreadsheet is made based on my hand written notes, but my hand writing wasn't the 'cleanest', and still isn't.

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This is very useful, thanks! I will give it a try in the near future. The first development time of 17 minutes mentioned in the spreadsheet is for Delta 100?

Edit: @Philippe-Georges can I request you to also share your process in the resources section of this site so that anyone who's looking for a good B&W reversal process in the future can search for the information more easily? Thanks in advance.

Klaus Wehner said:

I don't know the mentioned book, but I suppose that it is a bit older.
Probably the statements apply primarily to color slides. Black and white slides have somewhat different requirements.

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I quoted from 2009 edition of the book. You can check the book here. It doesn't specifically mention color reversal films when discussing DMax. But you do have a point regarding the difference between color and B&W slides.

Raghu Kuvempunagar said:

This is very useful, thanks! I will give it a try in the near future. The first development time of 17 minutes mentioned in the spreadsheet is for Delta 100?

Edit: @Philippe-Georges can I request you to also share your process in the resources section of this site so that anyone who's looking for a good B&W reversal process in the future can search for the information more easily? Thanks in advance.

Click to expand...

This process is good for any kind of B&W film emulsion, but for my personal use which was scanning for offset printing, I found the results on Delta 100 at box speed to be perfect.
You may not forget that I needed a trustworthy, easy to find and decently prized film that matched the same speed of the Polaroid type 54 (and by rare extension the type 55) and type Polaroid 664 Polapan Pro 100 – Peel Apart proof film as I used these in my studio.
For some assignments, B&W – and colour reversal (mostly Fuji Provia) were required simultaneously, so a good 100 ASA workflow was primordial...

And yes, you may put this spread sheet in the resource section.

Raghu Kuvempunagar said:

Interestingly, "Basic Photographic Materials and Processes" says this on DMax of reversal films:
"Although these films are capable of achieving densities above 3.0, the shadows are best reproduced at densities 2.7 and less depending on the contrast of the negative."

Click to expand...

Raghu, do yourself a favour and don't worry so much about numbers and Dmax values. It is not worth it. As the overall quality of a BW transparency is determined by several different factors, and not only by one. And personal preferences also play an important role. For example whether you do like a neutral or a warm tone slide more.
For example I have here Delta 100 (no clear base) 35mm transparencies with a very high Dmax of 3.6 (dr5), which looks not as good and less brillant than ADOX SCALA 50 (clear base) 35mm transparencies, processed in a lower Dmax process (Agfa Scala) with a Dmax of about 3.
And Delta 100 120 and TMY-2 120 (both clear base) results developed in Agfa Scala process also look better than the higher Dmax Delta 100 35mm results.
I have Aviphot Pan 80 transparencies with a very high Dmax (dr5), which have a too steep gradation curve and are too contrasty. Looking worse than the lower Dmax results of this film from other processes with lower Dmax. And I have very high Dmax results of this film developed by Klaus Wehner, which are excellent in all respects.
And then film characteristics play a role: For example I get significantly better highlight detail with ADOX SCALA 50 compared to other films.
Therefore:
Stop wasting time on "theory" and "number games" and just start making BW transparencies . Try different films and processes, and see, what you like best.

Best regards,
Henning

Philippe-Georges said:

This process is good for any kind of B&W film emulsion, but for my personal use which was scanning for offset printing, I found the results on Delta 100 at box speed to be perfect.
You may not forget that I needed a trustworthy, easy to find and decently prized film that matched the same speed of the Polaroid type 54 (and by rare extension the type 55) and type Polaroid 664 Polapan Pro 100 – Peel Apart proof film as I used these in my studio.
For some assignments, B&W – and colour reversal (mostly Fuji Provia) were required simultaneously, so a good 100 ASA workflow was primordial...

And yes, you may put this spread sheet in the resource section.

Click to expand...

Thanks. I created the resource here.

Henning Serger said:

Raghu, do yourself a favour and don't worry so much about numbers and Dmax values. It is not worth it.
Stop wasting time on "theory" and "number games" and just start making BW transparencies . Try different films and processes, and see, what you like best.

Click to expand...

I think you have completely misunderstood me. But I am not going to try correct your perception. Have a great day.