Old articles re acutance of films

[Alan Johnson]

On Flickr (need an account?} two articles from "Modern Photography":
https://www.flickr.com/photos/38552878@N02/20287720983/in/photostream/
https://www.flickr.com/photos/38552878@N02/23653609003/in/dateposted/
It seems that Panatomic-X was upgraded at around the time Adox KB 14 and 17 were introduced in Europe.I believe the Adox were also thin emulsions that gave less light scatter.They might have been low iodide emulsions. I don't know.
Most low speed films of this type appear to have been discontinued (Adox CHS 25.50;Plus-X} but the type of emulsion may live on in Tri-X.HP5+ and possibly Adox CHS 100 II.
Crawley called it "The acutance era".

 

[Ian Grant]

The "Acutance era" was largely a European pneumonia which had started just before WWII with developers from Beutler and Windisch etc.

So as well as these new thin layer films from Adox and Kodak there were also a plethora of acutance/high definition developers from all the European manufacturers. Ilford Hyfin, Kodak HDD, Tetenal Neofyn, Johnsons Definol, many of which were not available in the North American market (inc Kodak HDD).

Hans Windisch's book "Die Neue Foto Schule" also published in English as "The New Photo School" (1939) show a European approach that's diverging from North American practice which is really driven by a much faster uptake of smaller formats particularly 35mm and which accelerates even faster after WWII.

By 1956 Hans Windsich's book had been updated to become "The Manual of Modern Photography".

Interesting links Alan.

Ian

 

[MattKing]

a European pneumonia

Ian:

Do you have auto-correct engaged, by chance

 

[Alan Johnson]

Keep warm and read Windisch's book:
https://archive.org/details/TheManualOfModernPhotographyTheTechnique

 

[Ian Grant]

Ian:

Do you have auto-correct engaged, by chance

Yes Sometimes you don't spot it's changed a word !!!

Keep warm and read Windisch's book:
https://archive.org/details/TheManualOfModernPhotographyTheTechnique

I was told (on this forum) that Windisch's books were never published in English, strange as I have the first English edition (1939) and the 1956 book that you link to on the shelf here in my darkroom

Aside from the thin films (Adox and Plus-X), and the Acutance/High definition developers there was a third factor after the war that created Crawley's "Acutance Era". That was a huge improvement in lenses in particular the Summicron, which of course Crawley refers to in his articles.

Ian

 

[Gerald C Koch]

Acutance developers were a way to make an older thicker film appear more like a thinner one. These developers acted on that portion of the film closest to the surface. Little development occurred below this. Thus there was little light scatter as would happen if the entire emulsion were developed. Since the advent of thinner emulsions their raison d'etre has largely disappeared.

 

[Ian Grant]

That's an interesting point Gerald about most acutance and high definition developers being surface developers, and initially being designed for use with older thick emulsion films.

However their use increased very significantly here in Europe with the advent of slow much finer grained thin emulsion films from Adox then Ilford, Agfa and Kodak in the early 1950s, . That's the period of a noticeable commercial boom in Acutance and High definition developers which for the first time where made and sold by the major manufacturers. So in fact the developers loke Kodak HDD, Ilford Hyfin, Johsons Definol, Acutol & Acutol S etc were introduced after the move to thinner emulsions.

One problem with acutance and high definition developers is they aren't particularly fine grain so work their best with inherently fine grained films like the sloer Adox films , Pan F, Pan-X etc and the 100/125 ASA films. They weren't recommended for faster films where they caused excessive grain.

Ian

 

[Ian Grant]

Putting some dates to what Crawley calls the Acutance era in his 1960/61 series of articles:

Kodak HDD (High Definition Developer in their 1959 dealer catalogue
Johnsons Definol - released 1960
Ilford Hyfin - 1961

Ian

 

[Gerald C Koch]

Most low speed films of this type appear to have been discontinued (Adox CHS 25.50;Plus-X} but the type of emulsion may live on in Tri-X.HP5+ and possibly Adox CHS 100 II.
Crawley called it "The acutance era".

While this may have been true of earlier changes to Tri-X when Kodak moved all their films to a new coating facility Tri-X was completely reworked. Kodak tried to emphasize this by changing that film designation to 400TX. Many people seem to miss this change. Technologies learned from the development of T-grain films were incorporated in the new film. However, this is NOT to say that 400TX is a T-grain film. Le roi est mort vive le roi. Ilford HP5+ is a much more tradiitional film and it shows.

 

[Alan Johnson]

Steve Anchell agrees with you Gerald, the emulsion of Tri-X was changed:
https://books.google.co.uk/books?id...QgcMAA#v=onepage&q=tri-X 400 400Tri-X&f=false
Perhaps it is no longer acutance type.

 

[flavio81]

On Flickr (need an account?} two articles from "Modern Photography":
https://www.flickr.com/photos/38552878@N02/20287720983/in/photostream/
https://www.flickr.com/photos/38552878@N02/23653609003/in/dateposted/
It seems that Panatomic-X was upgraded at around the time Adox KB 14 and 17 were introduced in Europe.I believe the Adox were also thin emulsions that gave less light scatter.They might have been low iodide emulsions. I don't know.
Most low speed films of this type appear to have been discontinued (Adox CHS 25.50;Plus-X} but the type of emulsion may live on in Tri-X.HP5+ and possibly Adox CHS 100 II.
Crawley called it "The acutance era".

Note that acutance and high resolution are different things.

Manufacturers can try thinner emulsions and adding light-absorbing dyes, this increases the resolution.

But you can have high acutance in a low resolution film, like Tri-X for example.

Or lowish acutance with a high resolution film, by using any high resolution film with a developer that has silver solvent in it.

 

[flavio81]

While this may have been true of earlier changes to Tri-X when Kodak moved all their films to a new coating facility Tri-X was completely reworked. Kodak tried to emphasize this by changing that film designation to 400TX. Many people seem to miss this change. Technologies learned from the development of T-grain films were incorporated in the new film. However, this is NOT to say that 400TX is a T-grain film. Le roi est mort vive le roi. Ilford HP5+ is a much more tradiitional film and it shows.

Yes, you are correct. Moreover in a very good test out there on the web ("le pirate photo") you can see that 400TX is a bit finer grained than HP5+. TX looks very modern, to be honest.

 

[Ian Grant]

While acutance and high resolution are different the developers like Hyfin, Kodak HDD, Definol etc were designed to give high resoltion with a degree of acutance. it's also why they work best with the slowest films.

Crawley describes an example of using one of his acutance developers and getting extremely high resolution, I'd have to check the articles to find the reference. Ilford call Hyfin a an Acutance developer but Kodak call their similar developer High Definition (which means high resolution).

Ian

 

[Alan Johnson]

http://www.pirate-photo.fr/pages/viewpage.php?f=51&t=35
I hope this is the page to which flavio refers.

 

[Gerald C Koch]

Kodak never disclosed the composition of HDD. However if Crawley's guess is correct about the formula then HDD works slightly differently than other acutance developers like the Beutler formula. In contrast to all the others it is the amount of sulfite that is kept low rather than the amount of developing agent (Metol). Thus insuring the controlled decomposition of the Metol.

 

[flavio81]

http://www.pirate-photo.fr/pages/viewpage.php?f=51&t=35
I hope this is the page to which flavio refers.

Yes!

That's an excellent web page!

 

[Alan Johnson]

The link shows the differences in the grain and tonality of the films but I think it is possible to bring out differences in the films regarding acutance more clearly by using an acutance developer like pyrocat along with reduced agitation.

 

[Ian Grant]

I'm sure you're right Alan.

Crawley in the 5th article in his series which includes MAximum Definition developers talks about some developers being better siuted to certain films than others. He mentions Microphen giving better definition with Ilford films compared to Kodak, and the other way around with Microdol-X which he thinks gives slight less definition with Ilford films compared to Microdol but better with Koadk films.

My own experience with Pyrocat HD, which I've been using for 10 years now for all formats, is it does give exceptionally good acutance and definition, along with fine grain and you can increase the acutance with reduced agitation. While I've found Pyrocat excellent with all the films I use Delta 100 & 400, Fomapan 100 & 200, and in the past Acros and Tmax 100 & 400 it's superb with HP5.

I hadn't used HP5 since the release of XP1 then 2 and only started using it again about 8 years ago because I needed a fast film for hand held LF work, the results really surprised me in terms of definition, fine grain, tonal rage it's a truly magic film/ceveloper combination, What surprised me even more was push processing a sheet of HP5 to 3200 EI last Autumn and printing the negative 2 or 3 weeks ago was there was still no grain, this was at significant enlargement a section of what would be approx 24x30" if I'd printed the full frame.

Other developers are better with some film than others, Rodinal and the original AP/APX100 and also Tmax100 brings out the best with these films, in fact it was Agfa's recommended devleoper for APX100 and gave exceptionally good definition and fine grain with the film.

Ian