sepiareverb
genius and moron
Still some ACROS listed as in stock at Fotoimpex, 135 only tho.
charjohncarter
Veteran
I certainly am not an expert of Spectral Sensitivity Curves, but here are my impressions:
Delta 100 and FP4+ are very similar to each other, but appear to be less sensitive to blues (400 nm) than Acros 100. This makes the Ilford slightly more likely to need a yellow or more filter for rendering blue sky.
Tmax 100 is less sensitive to reds than Acros 100(+ for TMX portraits) but this seems slight. Tmax 100 is much more sensitive to blue (400nm and less nm) than Acros 100 which is good for sky.
These SSC are all done under different conditions so who knows what you will get with your developers. My personal experience is Acros and Agfa APX 100 were the closest, but both gone. (I never looked at the SSC of Agfa APX 100)
I hope someone with more knowledge than I have will rip my analysis apart and give use the real story of tonality.
Delta 100 and FP4+ are very similar to each other, but appear to be less sensitive to blues (400 nm) than Acros 100. This makes the Ilford slightly more likely to need a yellow or more filter for rendering blue sky.
Tmax 100 is less sensitive to reds than Acros 100(+ for TMX portraits) but this seems slight. Tmax 100 is much more sensitive to blue (400nm and less nm) than Acros 100 which is good for sky.
These SSC are all done under different conditions so who knows what you will get with your developers. My personal experience is Acros and Agfa APX 100 were the closest, but both gone. (I never looked at the SSC of Agfa APX 100)
I hope someone with more knowledge than I have will rip my analysis apart and give use the real story of tonality.
Freakscene
Obscure member
These SSC are all done under different conditions so who knows what you will get with your developers. My personal experience is Acros and Agfa APX 100 were the closest, but both gone. (I never looked at the SSC of Agfa APX 100)
It's here: https://125px.com/docs/film/agfa/apx100.pdf (Thanks Tim).
Acros is less sensitive to red than APX100, but the curve shape is as important as is the relative sensitivity at specific points. The point where the spectral response becomes insignificant in any given photo is also important.
I hope someone with more knowledge than I have will rip my analysis apart and give use the real story of tonality.
All I can really add is that spectral sensitivity is a predominant influence of the density (tone) that a specific colour is recorded on B&W film, but tonality as a whole is influenced by a lot more things than spectral sensitivity, largely the density/characteristic curve of the film-developer combination, and, if you wet print, the paper-paper developer combination.
If spectral response is really important to you, you can replicate colour response with filters, but if you use Acros because of its reciprocity characteristics and grain-speed characteristics, you are going to be doing more waiting around once Acros has run out - filtering any of the alternatives to obtain a similar spectral response costs light.
Marty

Leica MP, Summilux 35mm ASPH. 1/60@f4 Acros @ EI80, Xtol 1+1.
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maigo
Well-known
Film stocks are like dogs. A film stock you have grown to like is like a dog you have grown to love. When he’s gone he can be “replaced”, but never duplicated, and it will never be the same. Better not to attempt the impossible, but just love what is left on its own merits.
Barbara Streisand would agree.
"You can clone the look of a dog, but you can't clone the soul."
https://www.nytimes.com/2018/03/02/style/barbra-streisand-cloned-her-dog.html
Sent from my iPhone using Tapatalk
charjohncarter
Veteran
It's here: https://125px.com/docs/film/agfa/apx100.pdf (Thanks Tim).
Across is less sensitive to red than APX100, but the curve shape is as important as is the relative sensitivity at specific points. The point where the spectral response becomes insignificant in any given photo is also important.
All I can really add is that spectral sensitivity is a predominant influence of the density (tone) that a specific colour is recorded on B&W film, but tonality as a whole is influenced by a lot more things than spectral sensitivity, largely the density/characteristic curve of the film-developer combination, and, if you wet print, the paper-paper developer combination.
If spectral response is really important to you, you can replicate colour response with filters, but if you use Acros because of its reciprocity characteristics and grain-speed characteristics, you are going to be doing more waiting around once Acros has run out - filtering any of the alternatives to obtain a similar spectral response costs light.
Marty
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Leica MP, Summilux 35mm ASPH. 1/60@f4 Acros @ EI80, Xtol 1+1.
Thank you for your response, and I agree with you. I like TMAX 100 because it gives me the blue and red sensitivity I like but I have to say that I had to refine my developer, development, and agitation to get what I wanted. I appreciate your expertise, and again thank you. Of course, not many will care.
P.S. I liked Acros 100 but I personally can get easily what I want from TMAX 100. That is not a general statement it is my choice for film, developer, and more important development and exposure fine tuning, along with agitation scheme.
My last Acros 100 roll:

dave lackey
Veteran
Nice, John!
In the last three years, I have been very pleased with the results with Acros.
I am stunned to hear so many negative comments about this film, tbh... however, I have, since then, been enamored with Double X which is my favorite at the moment.
Meanwhile back at the ranch, while I dial in HP5+ with the Baby Rolleiflex, I am also looking forward to trying FP4+. There are so many things I want to work on but time is so restricted.
John, keep posting!
In the last three years, I have been very pleased with the results with Acros.
I am stunned to hear so many negative comments about this film, tbh... however, I have, since then, been enamored with Double X which is my favorite at the moment.
Meanwhile back at the ranch, while I dial in HP5+ with the Baby Rolleiflex, I am also looking forward to trying FP4+. There are so many things I want to work on but time is so restricted.
John, keep posting!
Freakscene
Obscure member
You are very welcome. Lovely family shot.

Marty
charjohncarter
Veteran
Above was taken on a very overcast day. That is something that is not common in California. Acros 100, although I never used it much, was very good, at least for me under these conditions.
BernardL
Well-known
Keep in mind that the Fuji spectrogram is witht a 5400K source, while the Foma spectrogram is with a 2850K source, which has *vastly* more energy in the red region of the spectrum. Ilford likewise uses a 2850K source. Even the temperature of the source is not enough to insure identical conditions, the dispersion law must also be specified (prism, grating?). Kodak provides a fully specified sensitivity curve, i.e. how many energy units per unit film area, at each respective wavelength, is needed to produce a reference net density, e.g; D=1 above B+F.Freakscene
Foma 100 has vastly *more* red sensitivity than Acros:
http://www.foma.cz/en/fomapan-100
https://www.fujifilmusa.com/shared/b...anAcros100.pdf
valdas
Veteran
deleted...
valdas
Veteran
deleted...
Freakscene
Obscure member
Keep in mind that the Fuji spectrogram is witht a 5400K source, while the Foma spectrogram is with a 2850K source, which has *vastly* more energy in the red region of the spectrum. Ilford likewise uses a 2850K source. Even the temperature of the source is not enough to insure identical conditions, the dispersion law must also be specified (prism, grating?). Kodak provides a fully specified sensitivity curve, i.e. how many energy units per unit film area, at each respective wavelength, is needed to produce a reference net density, e.g; D=1 above B+F.
Of course, there is about 3x as much red light as blue at 2850k, and slightly more blue than red at 5400k, but on a log scale that isn't that big a difference. I've measured spectral sensitivity for both films with a recording spectrograph and the higher red sensitivity in Foma 100 is real, and irrespective of the shape of the response the extinction point for the Foma is substantially further into the red.
One thing I've just noticed now is that Foma's sensitivity curve for Foma 200 in current technical data appears identical to their curve for Foma 100, whereas in my tests Foma 200 had a quite different response.
Agree entirely that Kodak's method, which is closer to equal intensity across the spectrum. One of the things that makes me uncomfortable about Kodak doing badly as a company is that they do this type of technical data so well.
Marty
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Ted Striker
Well-known
Wow, Rollei films are just about double the cost of Acros. Unreal.
Larry Cloetta
Veteran
Can’t help but notice in this thread and others that, when some have a personal preference for the tonality of a given film stock, they can’t or won’t say “I prefer the tonality of x.” It’s always “x has better tonality.”
helen.HH
To Light & Love ...
For Acros... A Fuji Digital. 
wink, wink
I'm a solid user of HP5 or Tmax 400
wink, wink
I'm a solid user of HP5 or Tmax 400
dave lackey
Veteran
Can’t help but notice in this thread and others that, when some have a personal preference for the tonality of a given film stock, they can’t or won’t say “I prefer the tonality of x.” It’s always “x has better tonality.”
Well said... preferences are after all, preferences.
I not sure I have preferences anymore...
With the disappearance of Fuji b/w, the day will likely hasten when no one has preferences. No worries... I am just having fun with what we have to work with today. I liked Kodachrome. It is gone. I liked all the b/w that is now gone. But, seriously, I can make the rest of the way.
KM-25
Well-known
Well said... preferences are after all, preferences.
I not sure I have preferences anymore...
With the disappearance of Fuji b/w, the day will likely hasten when no one has preferences. No worries... I am just having fun with what we have to work with today. I liked Kodachrome. It is gone. I liked all the b/w that is now gone. But, seriously, I can make the rest of the way.![]()
Fuji is discontinuing films, not Kodak and Ilford so I would put more optimism into your viewplane. We will have enough choices in B&W for years to come. Now if you are a dabbler or someone who relies on the film’s characteristics rather than substantial light and subject matter, your box of chocolates may have a reduced selection.
If all I had was one film to use, I would be just fine.
lawrence
Veteran
For Acros... A Fuji Digital.
wink, wink
Helen, I agree. Someone else mentioned that of all the films around today Acros looks the most 'digital', however to my eyes it doesn't look totally digital and has (had?) its own characteristics, quite different from TMX and D100. Whatever you may think of Acros as a film, it's sad to see another one bite the dust.
PRJ
Another Day in Paradise
Not a fan of Acros but I've used it and made some good prints with it. I stopped using it because I knew that Fuji would eventually discontinue it after they killed off Neopan 400. I went back to HP5. I am talking about 120 and 4x5 so the grain difference isn't really relevant.
Film is what you make it so pretty much anything works if you learn how to use it. It is inconvenient though when a film that you have become accustomed to disappears and you have to start from scratch. I've been there numerous times since Agfa went under.
Film is what you make it so pretty much anything works if you learn how to use it. It is inconvenient though when a film that you have become accustomed to disappears and you have to start from scratch. I've been there numerous times since Agfa went under.
Freakscene
Obscure member
Can’t help but notice in this thread and others that, when some have a personal preference for the tonality of a given film stock, they can’t or won’t say “I prefer the tonality of x.” It’s always “x has better tonality.”
One thing about having worked in a professional B&W film lab that offered custom development is that whatever I like or don't like, I needed to learn how to get the best out of all films, and also how to modify those optima for particular clients. It's why I spent a lot of time learning what factors contributed to different film tonalities. As David Vestal said "in art, anything goes".
Marty
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