PhotoStudio13 discontinuing Scala process

Klaus Wehner · Jan 24, 2022

Henning Serger said:
Well, that is your personal preference, but not a general physical requirement.

There is a misunderstanding here that I would like to clarify.

As I explained in my post #64, a maximum density of about 4.00 results from the practical requirements for high-quality projection.

Anyone can easily reproduce such tests with their own equipment and under their own conditions.
The value of 4.00 for the maximum density is the result of trials and accurate measurements.

It is the opposite of "personal preference".

I ask that this be taken into account. If you have any questions, I will be happy to help.

Kind regards
Klaus

Klaus Wehner · Jan 24, 2022

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

Black and white slides are the most stable image carriers in analogue photography.
They cannot simply "yellowing over the time", provided they are stored in a reasonably professional manner.
In order to chemically attack a black-and-white slide, very aggressive, strongly oxidising substances are needed.

Kind regards
Klaus

AgX · Jan 24, 2022

Klaus Wehner said:
In order to chemically attack a black-and-white slide, very aggressive, strongly oxidising substances are needed.

Yes,.... but gelatin layers as such can be fodder for some small animals, fungi and bacteria...

Nonethless I am a prponent of longtime storage on film.

Henning Serger · Jan 25, 2022

Klaus Wehner said:
There is a misunderstanding here that I would like to clarify.

As I explained in my post #64, a maximum density of about 4.00 results from the practical requirements for high-quality projection.

Klaus, as I have explained in my postings above, a Dmax of 4.0 is definitely not an absolute requirement or necessity for quality results in projection.
It is nice to have, but not a requirement / necessity. And the Dmax value is only one of many different quality parameters.
I am using the best quality projection equipment on the market, which is offering by far the highest brillance possible. Including the unique Da-Lite High-Power projection surface and projectors with the best light-power and best projection lenses.
And from all relevant viewing distances I get deep, real blacks on the screen also with lower Dmax values than 4.0.
It is not constructive or helpful to overemphasize the relevance of Dmax, or even make it a "fetish".
If quality results in BW projection would be dependent on a Dmax of 4.0, then BW projection would have been dead decades ago.

Best regards,
Henning

Henning Serger · Jan 25, 2022

Klaus Wehner said:
Black and white slides are the most stable image carriers in analogue photography.
They cannot simply "yellowing over the time", provided they are stored in a reasonably professional manner.
In order to chemically attack a black-and-white slide, very aggressive, strongly oxidising substances are needed.

Kind regards
Klaus

Klaus,
you know from our detailed personal talks in Paderborn about that topic:
Fact is that I have had this yellowing and quality destroying phenomenon only with the films you had developed for me in your specific process.
And that process started already about only one year after they were processed by you.
The affected films have been archived properly and in a professional way. The same way I archive all my other transparencies, too. And all my other transparencies are absolutely fine.

Best regards,
Henning

Klaus Wehner · Mar 12, 2022

I would like to say something briefly about Henning Serger's comments.
I know Henning Serger quite well from the German photo forum aphog. That is why I can assess his statements quite well.

Due to my scientific training, I am used to arguing and judging objectively and on the basis of facts. That is also how I would like to conduct this discussion here.

Several years ago (about 7 years ago) Henning Serger told me in a personal conversation that his black and white slides were "changing".
At that time I explained to him that there were no examples of such a thing up to now. But of course I was very interested and asked him to show me these "changed" slides.

Unfortunately, Henning Serger was not able to show me any proof of these changes. There was more than enough time and opportunity for this.

Therefore, I consider this to be a very singular and subjective complaint.

I am happy to have a factual discussion based on facts.

Thank you and best regards
Klaus Wehner

MamiyaBronica · Mar 12, 2022

Reading these last few statements makes me curious about the "real black" from this film. Many years ago I spent time with it with friends and we actually tried to get out a real, solid black from projection. We never got there. Our blacks would look chalky when projected.
We did stumble upon a beautiful "blueish" dark-grey tone though which kinda surprised us - we must have stared at it for 20 minutes. I suspect we somehow mis-fogged the film or something... We could never repeat it on another roll.

I wish I still had those slides - but I'm afraid they probably ended up thrown away.

Raghu Kuvempunagar · Mar 13, 2022

MamiyaBronica said:
Reading these last few statements makes me curious about the "real black" from this film. Many years ago I spent time with it with friends and we actually tried to get out a real, solid black from projection. We never got there. Our blacks would look chalky when projected.

Which process did you use? Was your DMax low?

Klaus Wehner · Mar 13, 2022

When developing black and white slides, it is very important that all chemical processes are quantitative (100%). Otherwise, reaction products can remain in the emulsion and disturb the quality of the slides. Therefore, the process must also be adapted exactly to one type of film.
If colour casts occur, this may indicate that the process has not been properly adapted.

That is why I have developed a method in my laboratory with which I can measure whether all chemical reaction steps have taken place quantitatively. I routinely use this procedure for quality control.

If this is guaranteed, you can see that each film has a weak colour tone of its own. This colour tone is visible but usually not disturbing.

Best regards
Klaus

Klaus Wehner · Mar 13, 2022

Foma is a company that strives to offer very affordable photographic materials. Unfortunately, the low price is often at the expense of quality.
I cannot recommend the current Foma R 100 and no longer routinely develop it.
The current emulsion has only a very low content of silver and can therefore no longer achieve high maximum densities.
My recommendation is the Ilford FP-4 (at ISO 100/21).
Unfortunately, the offers and the ratios often change quickly. You have to adjust to this again and again.
But I assume that the FP-4 will be available in the long term and with constant quality.

If there are any questions, I will be happy to help.
Yours sincerely
Klaus

AgX · Mar 13, 2022

Klaus Wehner said:
Therefore, the process must also be adapted exactly to one type of film.
If colour casts occur, this may indicate that the process has not been properly adapted.

That is why I have developed a method... If this is guaranteed, you can see that each film has a weak colour tone of its own.

To me this is a contradiction. Or do I have to differenciate somehow between "cast" and "tone"?

Klaus Wehner · Mar 13, 2022

Almost every film has a (weak) hue all its own.
In addition, however, there can be a (stronger) colour cast caused by an inappropriate process.
You have to differentiate between the two.
Is that understandable so far?

Yours sincerely
Klaus

miha · Mar 13, 2022

Klaus Wehner said:
Foma is a company that strives to offer very affordable photographic materials. Unfortunately, the low price is often at the expense of quality.
I cannot recommend the current Foma R 100 and no longer routinely develop it.
The current emulsion has only a very low content of silver and can therefore no longer achieve high maximum densities.
My recommendation is the Ilford FP-4 (at ISO 100/21).
Unfortunately, the offers and the ratios often change quickly. You have to adjust to this again and again.
But I assume that the FP-4 will be available in the long term and with constant quality.

If there are any questions, I will be happy to help.
Yours sincerely
Klaus

Is the FP4+ base clear enough for projection?
135 only or do you process 120 and LF as well? Thanks.

Klaus Wehner · Mar 13, 2022

The film base is not a problem.
If it has a slightly higher density of 0.10...0.15, this is not visible in the projection.
The important thing is that the film has a neutral colour tone and reaches a sufficiently high maximum density.
I routinely process 135 and 120 films.

Yours sincerely
Klaus

AgX · Mar 13, 2022

Is your process applicable on LF (streaks or so)?
Economics aside.

Klaus Wehner · Mar 13, 2022

For me personally, I also develop slides in 4x5 to 8x10 inch format.
But it is a lot of extra manual work. That's why I don't offer it as a service.
Technically, there are no problems. I use rotary development in a JOBO tank for this.
I have a special chemistry for the reverse development of photo paper. But that also works without problems.

Yours sincerely
Klaus

Raghu Kuvempunagar · Mar 13, 2022

Klaus Wehner said:
I have a special chemistry for the reverse development of photo paper. But that also works without problems.

Interesting! What is special about this chemistry and why's a special chemistry needed specifically for paper? Is there any shortcoming you found with Dektol or similar print developers that are used in paper reversal?

Klaus Wehner · Mar 13, 2022

Also for the reverse development of photo paper, the process must be precisely adapted to the paper.
A "70% result" can also be achieved with simple means. But if you want to achieve optimal quality, you have to make a greater effort.
Typical mistakes are: no pure white, insufficient maximum density, uneven development...

Yours sincerely
Klaus

Raghu Kuvempunagar · Mar 13, 2022

Klaus Wehner said:
Also for the reverse development of photo paper, the process must be precisely adapted to the paper.
A "70% result" can also be achieved with simple means. But if you want to achieve optimal quality, you have to make a greater effort.
Typical mistakes are: no pure white, insufficient maximum density, uneven development...

Who can disagree with this? But it doesn't tell specifically why Dektol or similar developers are inadequate for achieving optimal quality.

Can you show a few examples of photographic paper reversed in your optimized process?

Klaus Wehner · Mar 13, 2022

each paper has its own requirements. Where exactly the problem lies varies greatly and is different for each paper.
It can be the pH value, the alkali used, the anti-fogging agent used... there are so many factors.
Just try it out: if you are satisfied with the result, then everything is fine!
With the reversal process you should achieve the same densities as with the normal paper process.

Best regards
Klaus

Raghu Kuvempunagar · Mar 13, 2022

Klaus Wehner said:
each paper has its own requirements. Where exactly the problem lies varies greatly and is different for each paper.
It can be the pH value, the alkali used, the anti-fogging agent used... there are so many factors.

Hmmm.. In contrast to your self-admittedly complicated process for photo paper reversal, the venerable Kodak Photo Engineer, Ron Mowrey, gave a simple process here:

https://www.photrio.com/forum/threads/paper-negative-reversal-process.74130/#post-1029646

Key thing is to get the exposure right (paper speed is a complicated thing) and using the right filters (for VC paper) for contrast control. But the reversal process as detailed by Ron is quite simple. Have you tried it?

BTW I would like to see some examples of photo paper reversed in your optimized process if you can share some pics.

Klaus Wehner · Mar 13, 2022

The matter is not so complicated after all.

There is only one criterion: are you satisfied with your results or are you not?
But then there is also an objective criterion: does the reversal process achieve (approximately) the same densities as the normal paper-positive process?

This is often not the case with the low densities (highlights).

The reversal process you mentioned is a well-known standard process. Apart from the fact that it uses potassium dichromate (which is now banned in Europe because of its toxicity), I am also not sure whether it actually leads to the desired quality.

But quite clearly: the assessment is subjective!

Yours sincerely
Klaus

Raghu Kuvempunagar · Mar 14, 2022

Klaus Wehner said:
The matter is not so complicated after all.

There is only one criterion: are you satisfied with your results or are you not?
But then there is also an objective criterion: does the reversal process achieve (approximately) the same densities as the normal paper-positive process?

This is often not the case with the low densities (highlights).

The reversal process you mentioned is a well-known standard process. Apart from the fact that it uses potassium dichromate (which is now banned in Europe because of its toxicity), I am also not sure whether it actually leads to the desired quality.

But quite clearly: the assessment is subjective!

Thanks for your insights. Much appreciated.

Klaus Wehner · Apr 16, 2022

Just one more quick clarification:
my reversal process for photographic paper consists of 3 baths and does not require potassium dichromate or thiocyanate. It is simple and not complicated at all.
Best regards
Klaus

AgX · Apr 16, 2022

But the film-reversal process you use in your commercial lab is a 10-bath, 20-step process.

PhotoStudio13 discontinuing Scala process

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