Acutance Films?

[Alan Johnson]

One thing not clear. DF wrote above of the native acutance of T-Grain films being so much higher than old films it defies comparison. OTOH Leica expert Erwin Puts wrote on T-grain compared to Panatomic X "...tabular shaped crystals....acutance was lost..."
www.imx.nl/photosite/technical/bwstateofart.html
Is there an explanation for this apparent difference?

 

[df cardwell]

One thing not clear. DF wrote above of the native acutance of T-Grain films being so much higher than old films it defies comparison. OTOH Leica expert Erwin Puts wrote on T-grain compared to Panatomic X "...tabular shaped crystals....acutance was lost..."
www.imx.nl/photosite/technical/bwstateofart.html
Is there an explanation for this apparent difference?

I believe this is what Alan is referring to:

"Where I get confused is comparing films evolved from the '50 and '60s to T-grain films. The native acutance of T-Grain films is so much higher than old films that it defies comparison."

Specifically, I intended to refer to Kodak's Plus X and Tri X, Ilford's FP4+, HP5+, and Pan F. It would have been better, I suppose, had I just said it.

Thanks.

 

[sanking]

I believe this is what Alan is referring to:

"Where I get confused is comparing films evolved from the '50 and '60s to T-grain films. The native acutance of T-Grain films is so much higher than old films that it defies comparison."

Specifically, I intended to refer to Kodak's Plus X and Tri X, Ilford's FP4+, HP5+, and Pan F. It would have been better, I suppose, had I just said it.

Thanks.

The T-grain films definitely have higher resolution when compared to traditional films of the same ASA. This can be easily measured with simple resolution targets in contact printing where you eliminate the camera system as a source of error.

All of us are rightly concerned with sharpness, but bear in mind that greater acutance is not always desirable. Most people are aware that certain developers known as very high acutance develpers, such as FX-1, Neofin Blue and Beutler, do not always (in fact often do not) produce results that are as pleasing pictorially as simple acutance or high acutance developers. In image making as in life there are often negative consequences for insisting on, and getting, more than we need.

Sandy

 

[dancqu]

The T-grain films definitely have higher resolution when
compared to traditional films of the same ASA. This can
be easily measured with simple resolution targets in
contact printing where you eliminate the camera
system as a source of error. Sandy

I take that to mean a resolution transparency in
contact with the subject film. No optics are involved.
Is that the way a film's unhindered maximum resolution
is measured? I suspect a more sophisticated method is
used although I've not a clue as to what it might be.

Be that as it may, without the optics it is not a
real world test and likely by a long shot. Users of the
"traditional" films I'm quite sure will back that up. The
print is the final measure of a film's capability and
that is where it will show.

I've not yet but will be giving the material at
www.normankoren.com a study. Don't be put off
by the electronics. He has quite a bit indicated
dealing with optics and film. Dan

 

[sanking]

I take that to mean a resolution transparency in
contact with the subject film. No optics are involved.
Is that the way a film's unhindered maximum resolution
is measured? I suspect a more sophisticated method is
used although I've not a clue as to what it might be.

Be that as it may, without the optics it is not a
real world test and likely by a long shot. Users of the
"traditional" films I'm quite sure will back that up. The
print is the final measure of a film's capability and
that is where it will show.

I've not yet but will be giving the material at
www.normankoren.com a study. Don't be put off
by the electronics. He has quite a bit indicated
dealing with optics and film. Dan

If what you want to do is mesure the resolution of a film, as opposed to the resolution of a lens or of a system, it must be done in a way that eliminates the differences that could be introduced by the lens or camera system. One way to do this is with one of the chrome on glass resolution targets, contact printiing the target to piece of film or paper.

However, resolution is only one measure of a film's potential, and I would not argue with the proposition that the final measure of a film's potential is the print. Most proponents of both modern T-grain films and traditional films would gladly concede this point.

Sandy

 

[Peter Schrager]

Thread

I just wanted to thank all the contributors to this thread...really interesting information
Best, Peter

 

[avandesande]

It seems to be much harder to 'starve' t-grain films through semi stand development.
I am going to try stand development with acros.

Where I get confused is comparing films evolved from the '50 and '60s to T-grain films. The native acutance of T-Grain films is so much higher than old films that it defies comparison. Yet new films tend to be resistant to the 'FX' we tend to associate we good acutance: edge, adjacency, etc., etc., etc.

.

 

[nworth]

Sandy;

Among onther things:

An acutance film is one with reduced internal reflections. This is accomplished by adding an acutance dye to the film. This dye decreases speed though, so you need a fast emulsion with fine enough grain to allow the use of added dyes to improve sharpness without a severe penalty in grain.

...

PE

I first remember this term "high acutance" being applied to films in the late 50s. It was used to describe the then new thin emulsion films, like KB14. The principle was the same then as what you describe now, although the current T-grain emulsions did not exist. Usually, but not always, a dye was not used to decrease the dispersion. The affect was accomplished, more or less, by simply using a more thinly coated emulsion. Obviously, high sensitivity was required if less emulsion (silver) was used. The high acutance, thin emulsion films were a cult thing at first. They tended to have high contrast and low speed. But around 1957 Kodak jumped on the bandwagon and redesigned all its films using high acutance, thin emulsion technology. Everyone benefited from their detailed and exhaustive research to make these emulsions effective. It was during this time that the modern Tri-X first appeared.

 

[Peter Schrager]

Acros

Avensdale-I have tried Acros with stand dev. according to Steve Sherman. Was a little less than impressed but I only tried it once. I think I over did it. There were however some nice effects but overall was not a winner to me. Please go ahead and do this and report back to us. Unfortunately most of my processing does not allow me the timeframe to do stand or semistand; I simply do too much processing...
Best, Peter

 

[avandesande]

Peter, use Rodinal!

 

[Gerald Koch]

Thanks Peter, that is the nex step: RODINAL. I've been draging my feet using Rodinal until there is a supply in Adoramma/B&H. The little bit I have on hand I've been guarding.

Rodinal is not a very good acutance developer. Something like the Beutler formula would be a better choice. This has to do with the rather unique sensitivity of Metol to bromide.

 

[sanking]

It seems to be much harder to 'starve' t-grain films through semi stand development.
I am going to try stand development with acros.

I have never tried Acros with either stand or semi-stand development. On the other hand, I have gotten really nice edge effects with TMAX-100 in roll film format with semi-stand development using at least two different high acutance developers.

Sandy

 

[dancqu]

Rodinal is not a very good acutance developer.
Something like the Beutler formula would be a
better choice. This has to do with the rather
unique sensitivity of Metol to bromide.

"High Acutance Developers" by Gerald Koch. I think
that must be one of your articles I refer to now and
then when reading from Patrick Dignan's Classic B&W
Formulas. If so, when was it written?

Through out this thread I've noticed a lack of attention
to the needed high activity of developers used for
high acutance results. Dan

 

[sanking]

"
Through out this thread I've noticed a lack of attention
to the needed high activity of developers used for
high acutance results. Dan

What do you mean by the term high activity? Are you refering to the commonly held view that high acutance developers need to work at relatively high pH levels?

Sandy

 

[dancqu]

What do you mean by the term high activity?
Are you refering to the commonly held view that
high acutance developers need to work at
relatively high pH levels? Sandy

At ph levels which can be achieved with a carbonate.
I can find no flaws in Mr. Koch's logic. Dan

 

[Dave Krueger]

Well, I have quickly become lost. I appreciate the comments regarding personal preferences when it comes to the appeal of potentially exaggerated edge effects. I'm still undecided about whether edge effects or even unsharp masking would appeal to me in terms of my own work. As of yet, I haven't experienced these effects enough to make a decision. I'm not fundamentally opposed to dramatic effects in pictures. They are just another tool that I would like to master someday. But, I agree that enhanced edges do not a good picture make.

In any case, from what I gather from this and the other thread that Alan mentioned, if edge effects are what I'm after, I'm getting the impression that I should be playing with the likes of Beutler, FX-1, FX-2, or Rodinal.

As for the sharpness of the print sections I posted, it may be correct that they are not as sharp as they could be. Or it could be that my scanner is crap. The print looks pretty crisp, but I've always heard that print materials are not meant to be enlarged to that extent. In other words, I think 1200 dpi may be beyond the limits of the paper. Nonetheless, I probably would have done better to use my other scanner.

In response to my original question, I getting the feeling that edge effects would tend to be more apparent in an image that has a lot of fine detail. Perhaps I should be looking for the effect in the grass rather than on the siding and door frame in the test picture, although I still don't see much there either.

Also, I question whether PL100 is even a good film to be looking for edge effects. Personally, I think TXP320 appears to be a much sharper film than PL100 with either Xtol or Pyrocat. Of course, that's just based on my experiences and subjective opinion.

 

[Tom Hoskinson]

I have never tried Acros with either stand or semi-stand development. On the other hand, I have gotten really nice edge effects with TMAX-100 in roll film format with semi-stand development using at least two different high acutance developers.

Sandy

I've also gotten very nice edge effects with TMAX-100 35mm and 120 rollfilm developed semi-stand using Pyrocat-MC.

 

[Dave Krueger]

Well, I have quickly become lost. I appreciate the comments regarding personal preferences when it comes to the appeal of potentially exaggerated edge effects. I'm still undecided about whether edge effects or even unsharp masking would appeal to me in terms of my own work. As of yet, I haven't experienced these effects enough to make a decision. I'm not fundamentally opposed to dramatic effects in pictures. They are just another tool that I would like to master someday. But, I agree that enhanced edges do not a good picture make.

In any case, from what I gather from this and the other thread that Alan mentioned, if edge effects are what I'm after, I'm getting the impression that I should be playing with the likes of Beutler, FX-1, FX-2, or Rodinal.

As for the sharpness of the print sections I posted, it may be correct that they are not as sharp as they could be. Or it could be that my scanner is crap. The print looks pretty crisp, but I've always heard that print materials are not meant to be enlarged to that extent. In other words, I think 1200 dpi may be beyond the limits of the paper. Nonetheless, I probably would have done better to use my other scanner.

In response to my original question, I getting the feeling that edge effects would tend to be more apparent in an image that has a lot of fine detail. Perhaps I should be looking for the effect in the grass rather than on the siding and door frame in the test picture, although I still don't see much there either.

Also, I question whether PL100 is even a good film to be looking for edge effects. Personally, I think TXP320 appears to be a much sharper film than PL100 with either Xtol or Pyrocat. Of course, that's just based on my experiences and subjective opinion.

Well, this post was meant for another thread (Edge Effects with Pyrocat HD). Sorry. That's what I get for having so many windows open at once...

For some reason, there is no "edit" button, else I would have just deleted the text.

-Dave

 

[noseoil]

"Also, I question whether PL100 is even a good film to be looking for edge effects. Personally, I think TXP320 appears to be a much sharper film than PL100 with either Xtol or Pyrocat. Of course, that's just based on my experiences and subjective opinion." Dave

Edge effects are very good with PL100, but development time and type of agitation are the determining factors. With "normal" development, edge effects aren't there in PL100 (I mean development in which standing of the film is usually a minute or less or agitation cycles frequent). With minimal, stand or semi-stand development, the effects are apparent. What is needed is a developer which can be slowed down by dilution (or temperature, or both) to the point where these contrast changes can naturally occur, due to the extended development time. The film's internal structure then comes into play.

We are talking about two different things here. The film's inherent acutance is one part of the equation, the film's reaction to differing methods of development is another subject entirely. While edge effects are subtle, the overall effect in an image, with respect to shadow detail and tonality, can be stunning (what Sandy calls micro-contrast). tim