Fuji Acros 100 and Contrast Filters

As I began my return to analog photography, I choose Fuji Acros 100 as my primary 120 film. While I've generally been pleased with the results, I do notice that Acros does not respond as I had anticipated to the use of a #25 red contrast filter. The skies really did not darken much at all. I've done some research and it appears the some of the characteristics that make Acros so popular contribute to its "resistance" to black and white contrast filters.

In my humble arsenal of contrast filters, the #16 Yellow-Orange filter seems to illicit the most response. Even then, not a significant increase in contrast. I've read where some folks recommend using a #13 green filter to get the best contrast response with Acros 100. They even suggest using the green filter in combination with a polarizing filter.

Before I spent too much more money purchasing filters for my Hasselblad lenses, I was hoping to get some feedback and suggestions from this group. Thank you.

Jeff

The author of this video seems to suggest that 100 Acros works fine without any need for colour filters.
It also covers his reviews of different developers for that film.

All this is interesting to one who has had a love/hate relationship with Fuji B&W films for 25 years. During my years in Southeast Asia I used many rolls of the old Neopan SS, which gave lovely mid tones but had a lousy grain structure. The new Acros resolved the grain problem and gave somewhat more kick to the shadows but I found it reacted (and still reacts) in odd ways to the harsh light of Asian beaches and Australian landscapes, with washed out highlights and greatly reduced tones in the mid greys. This largely restricted me to using the Fuji films on cloudy days.

In those years I kept light yellow and deep yellow filters on my Nikkormats and Rollei TLR, and also often used orange, all of which helped the overall tones. I never used green and almost never red or a polariser. My shooting style has now changed and I mostly use polarisers but not the other filters.

As for processing, neither Neopan nor Acros gave me results I regarded as satisfactory in Kodak D76 and on the one or two occasions I processed these films in Rodinal, sharpness was acceptable if not glorious and grain not unlike a sandy beach made it very difficult to print even to 5x7" with a diffuser enlarger. A few rolls developed in home brewed Leica two bath developer were more satisfying, with good assorted grey tones across the spectrum, clean whites, no overly deep blacks. Fine for scanning, less so for prints in my traditional darkroom.

When the revamped TMax 100 and 400 emulsions came out about 12 years ago, I returned to Kodak films and all but gave up on Acros, as oddly TMax prices were (and still are) cheaper than Acros prices in Australia. However, in 2011 I was able to buy a large stock of 35mm Neopan SS very cheaply and not long after several bricks of 120 Acros came my way, virtually free. They are in my film fridge now. I always felt there was something almost 'elemental' about the old Neopan SS, and now having watched the interesting video from Keith, I am again tempted to revisit the two films and process them in the newer developers now available. I have large stocks of the two and there may be hope.

Oddly, the best results I ever had from Acros were from a batch of six rolls I had processed in a small photo studio darkroom in a Malaysian town in 2002. The negatives that were returned to me glowed with brilliant tones, unlike anything I had been able to achieve at home. Queries revealed the local photographer was out of film developer and developed them four minutes in Dektol 1+2. 5x7" prints are my standard presentation prints and those I did from these films were excellent. Strange but true...

Dear Jeff,

Welcome back. The good news is that filters work the same way for all films. As you know, they allow more light of the filter color to pass thus brightening that color when printed. The difference is that the newer films respond more evenly across the visible spectrum. Try adding your polarizer in front or keep a graduated neutral density filter around to darken skies.

Good luck,

Neal Wydra

acros is Orthopanchromatic, so it drops off the color response if i remember correctly, around 620, so it is not very sensitive to red light. I found that using a red filter on it really only acts as a ND filter, just adding exposure rather than cutting off light. I use an orange on it and find that is about as dark as I can go on it.

It's been a long work day and I just got the time to read everyone's excellent comments. I sincerely appreciate each of your comments and find them most helpful.

The term "orthopanchromatic" is entirely made up and has no scientific validity. The term is a fiction dreamed up by marketing weasels. Either a film is orthochromatic or it is panchromatic but not both. However one can speak of a film having lessened or extended red sensitivity.

There are only four kinds of emulsions as far as spectral response.

1. Unsensitized - responds only to ultra-violet, violet and blue wavelengths.
2. Orthochromatic - sensitivity expanded into the green region of the spectrum.
3. Isochromatic - Similar to orthochromatic but with lower but still high blue sensitivity. Produces a more natural tonal response. Some additional sensitivity to yellow light.
4. Pancromatic - Sensitive to the entire visible spectrum. Special dyes can extend this into the infra-red.

thank you greald koch!!! for once and for that term needs to disappear
peter

Peter Schrager said:

thank you greald koch!!! for once and for that term needs to disappear
peter

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Thanks. This term has annoyed me for years. That and another weaselism "silver rich" films. Modern films contain much less silver than in the past thanks in part to better dyes.

BTW I expanded my post to explain what sensitizations do exist.

you and a few others are always here to guide us!! I miss my friend Tom Hoskinson..he was so generous and so are you!!
thank you very much from a real photographer... ( just as a quick aside please no one ever touch the phony rollei 80s..repackaged surveillance film for $10/roll..talk about scams!!)

Gerald C Koch said:

The term "orthopanchromatic" is entirely made up and has no scientific validity. The term is a fiction dreamed up by marketing weasels. Either a film is orthochromatic or it is panchromatic but not both. However one can speak of a film having lessened or extended red sensitivity...

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Gerald,

That may all be well and good, but the question still remains: Does Acros have reduced red sensitivity when compared to other B&W films and would that reduce the usefulness of red filters with that film?

I've looked at the spectral responses of the Fuji, Ilford and Kodak B&W films. The Fuji films seem to drop off steeply at about 620nm while the others have sensitivity up to ~650nm. Whether the extra 30nm of sensitivity makes a significant difference is the question.

Maybe we can address this, which is the OP's main concern.

Doremus

Hi Jeff:

i currently use Acros with contrast filters, and my comment would be to use a #8 yellow to start. Knocking the blue end of the spectrum out of the response will have the most dramatic effect on imaging of any filter. Mild filtration will create a broad spectrum response, and very beautiful gradation.

As a more advanced option is the yellow-green filter, which actually knocks down some of the red response in addition to knocking down the blue spectrum---quite the opposite of your current situation with the red filter. A yellow-green filter will make trees stand out, while making red rock look more natural in response. It is a beautiful filter, and not used to the extent it should be. The yellow-green filter is perhaps the most natural to the eye of any filter response.

Unless you are photographing skies and skies only, I would stay away from the orange and red filters, particularly with Acros. It might lead to dramatic contrast for the sky, but it will render trees, rocks and foreground looking off-tone. People tend to over-filter with b&w film, when a delicate touch often creates a better response---and with far less loss of light.

Pete

RE the term "orthopanchromatic": It may be true that the term isn't 'official'. However, the English language and scientific terms are 'live', meaning new words and terms are created and older outdated terms eventually die. Science and mankind change (hopefully for the better) when something comes along that's significantly different it absolutely makes sense to create a new descriptive or modify existing ones to easily/quickly refer to that new thing. Otherwise, we'd have to constantly pen an entire paragraph to refer to something that a single word can refer to.

Doremus Scudder said:

Gerald,

That may all be well and good, but the question still remains: Does Acros have reduced red sensitivity when compared to other B&W films and would that reduce the usefulness of red filters with that film?

I've looked at the spectral responses of the Fuji, Ilford and Kodak B&W films. The Fuji films seem to drop off steeply at about 620nm while the others have sensitivity up to ~650nm. Whether the extra 30nm of sensitivity makes a significant difference is the question.

Maybe we can address this, which is the OP's main concern.

Doremus

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The red sensitivity of the film is not the problem. If you look at the spectral response curve you will see that Acros has reduced blue sensitivity (the significant dip about 490 nm). On the semi-log plot this is a reduction of over 50%. Skies will appear darker than for other films. So a red filter will have less effect. So if the OP is unhappy with Acros then he needs to find a different film with a more conventional response.

http://www.digitaltruth.com/products/fuji_tech/AF3-083E.pdf

There is useful information in curves such as this and anyone into filters needs to consult them.

Old-N-Feeble said:

RE the term "orthopanchromatic": It may be true that the term isn't 'official'. However, the English language and scientific terms are 'live', meaning new words and terms are created and older outdated terms eventually die. Science and mankind change (hopefully for the better) when something comes along that's significantly different it absolutely makes sense to create a new descriptive or modify existing ones to easily/quickly refer to that new thing. Otherwise, we'd have to constantly pen an entire paragraph to refer to something that a single word can refer to.

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Not only is it not official it also makes no sense. You just can't go around willy-nilly inventing new science terminology. There are international organizations that are responsible for this. Science does not change rather the extent of human knowledge changes. In this case saying that a film has extended or lessened red sensitivity is not a paragraph. In fact doing so is easier to understand.

Gerald C Koch said:

You just can't go around willy-nilly inventing new science terminology.

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I agree entirely with this, but have one question:

Is "willy-nilly" science terminology?

MattKing said:

willy-nilly science terminology

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This is commonly known as "Marketing."

Ha ha ha...

well, looks like i raised a shi* storm with the term i used. Guess I should not copy and paste from fujis web site again. sorry for stirring the pot it was not my intention, just trying to show that it has less red sensitivity than other films.

Gerald C Koch said:

The red sensitivity of the film is not the problem. If you look at the spectral response curve you will see that Acros has reduced blue sensitivity (the significant dip at 500 nm). On the semi-log plot this is a reduction of over 50%. Skies will appear darker than for other films. So a red filter will have less effect. So if the OP is unhappy with Acros then he needs to find a different film with a more conventional response.

http://www.digitaltruth.com/products/fuji_tech/AF3-083E.pdf

There is useful information in curves such as this and anyone into filters needs to consult them.

Click to expand...

So, how would you describe a panchromatic film that is less sensitive to "red" than other panchromatic films?
One of my old favorite B&W films, Kodak Verichrome Pan (not Verichrome, an Ortho film), was similar (also not a "scientific" term) to Across. I don't remember orthopanchromatic used as a "selling" word in peddling films. I think it is more of a descriptive term of the films, not scientific, nor is/was it meant to be. Verichrome Pan was advertised and sold as an "amateur" film but many professionals, with many years experience, preferred it and bought it in quanity for their work. All of us, professionals and advanced amateurs alike, hated to see it discontinued........Regards!

oldtimermetoo said:

So, how would you describe a panchromatic film that is less sensitive to "red" than other panchromatic films?
One of my old favorite B&W films, Kodak Verichrome Pan (not Verichrome, an Ortho film), was similar (also not a "scientific" term) to Across. I don't remember orthopanchromatic used as a "selling" word in peddling films. I think it is more of a descriptive term of the films, not scientific, nor is/was it meant to be. Verichrome Pan was advertised and sold as an "amateur" film but many professionals, with many years experience, preferred it and bought it in quanity for their work. All of us, professionals and advanced amateurs alike, hated to see it discontinued........Regards!

Click to expand...

1. Panchromatic with reduced red sensitivity. Panchromatic means sensitive to all visible wavelengths. It is a relative term. However it does NOT mean that the response is linear and the curve is a flat line.

2. Orthochromatic is certainly a scientific definition for film you will see it in many photography books.

3. People including myself liked Verichrome Pan because it had a unusually large latitude. It was multicoated having both a slow and a fast emulsion layer. This was done because it was intended for simple box cameras that lacked any exposure adjustment.

4. I repeat again the OP's "problem" is not caused directly by the red sensitivity of Acros. The BLUE sensitivity has been reduced by more than 1 stop compared to other comparable films. Think of this as a builtin red filter. Adding another one on the lens is not going to have the anticipated effect. In fact the film recommends using a yellow filer not a red one to emphasized clouds.

5. The spectral sensitivity of film is determined by the choice of sensitizing dyes. Some are better than others. However these dyes are hard to make and VERY expensive. So often it is the bottom line that matters most. However as far as the blue sensitivity is concerned Fuji intended the film to respond more closely with the human eye.

deleted

Gerald,

I see your point about the reduced sensitivity of Acros around 490nm. However, upon checking the transmission spectrum for the #25 filter, which falls off below 50% transmission at about 600nm, I'm wondering if the very slim overlap between 600nm and 620nm where Acros tends to fall off sharply doesn't also present a factor here (a higher-than-usual filter factor to be exact). I might think that there were a (non-scientific) "double-whammy" happening here when using a #25 with Acros: both suppressing the already lowered blue-green response and lack of adequate transmission vs film response in the red resulting in a higher filter factor that probably isn't being applied which would result in darker skies when compared to more usual pan films coupled with underexposure from the very little remaining amount of film sensitivity left when the #25 is used.

For what it's worth, take a look at Fuji's description of Acros on the first page of the Fuji data sheet you linked to for the spectral response curve. The Fuji technicians and scientists use the very term you so disparage, i.e., "Orthopanchromatic" for this film. I might tend to be a bit more accepting of the term to describe a panchromatic film with reduced red sensitivity in the light of this...

Best,

Doremus

Hi Doremus,

There is, as you say, also a red component to the general problem. But the OP question centered around darkening skies. The cited film suggests using a yellow filter to achieve this not a red one.

Sorry but I stand firm orthopanchromatic is a made up term. It was dreamed up to explain faulty sensitization of Efke films some years ago toward the red end of the spectrum to make a problem seem a feature. (As I pointed out these sensitization dyes are hard to synthesis and thus expensive. The bottom line triumphs over quality.) Find the term in Haist and I will give the matter another thought. Unfortunately marketing departments now write documentation not scientists. Does the term say anything meaningful? Is the film more ortho than panchromatic or vice versa? We don't know. Looking at the sensitivity curve Acros could just as well be called "isopanchromatic" having reduced blue sensitivity and higher yellow.

Jerry

There is no single word to describe the spectral sensitivity; please refer to the graph in the film's datasheet.