Acutance - is there something real behind the hype?

[AlanC]

Many thanks Sandy. Since last posting I have found some plastic tubing that should work instead of the tin.
I will start with Adox (efke) 100. I know how to develop this with "normal" agitation in Pyrocat HD, so will be able to make prints from normally developed negatives and compare them with same subject prints made from negatives developed as you suggest.

Alan

 

[sanking]

Many thanks Sandy. Since last posting I have found some plastic tubing that should work instead of the tin.
I will start with Adox (efke) 100. I know how to develop this with "normal" agitation in Pyrocat HD, so will be able to make prints from normally developed negatives and compare them with same subject prints made from negatives developed as you suggest.

Alan

Alan,

You should make sure to wet the film before placing it in the tubes. If you don't the back of the film may stick to the wall of the tube making it very hard to remove.

Sandy King

 

[AlanC]

Thanks again Sandy. As I am itching to try this I may try a test first in the Paterson tank, where only the edge of the film touches the tank.

Alan

 

[Alan Johnson]

The original Kodak work by Jones & Higgins, Wolfe & Eisen relating the slope of the edge density to perceived sharpness is on p127-132 here (takes a while to download).
They probably used D-76 and missed ocurrence of edge effects.
http://image.eastmanhouse.org/taxonomy/term/387

 

[RalphLambrecht]

The original Kodak work by Jones & Higgins, Wolfe & Eisen relating the slope of the edge density to perceived sharpness is on p127-132 here (takes a while to download).
They probably used D-76 and missed ocurrence of edge effects.
http://image.eastmanhouse.org/taxonomy/term/387

Wonderful resource Alan. Thanks for the link.

 

[dancqu]

Assuming that you have some way of allowing the film
to stay still between agitation cycles ... Sandy

Easy, use a tray and separators. Liken a sheet of film
to a sheet of light weight RC paper. The method I suggest
is the same as the method I use to wash paper, long soaks.
The separators are of hydrophobic material, light weight
polyester batting.

In the case of washing paper some water is placed in a tray
with a separator at bottom followed by a print a separator,
repeating until the tray is full or no more prints.

For agitation the wash water, after some time, is poured
into a second tray and stirred. The separators and
and prints are then transferred from the first
tray to the second. For prints fresh water
is used the beginning of each cycle.

Substitute developer and film for water and print, include
as many transfers as is thought needed and you've the
tray way to stand development for film.

I've developed sheet film via tank and hanger, tray,
and the, IIRC, Yankee sheet film tank. I've never
had occasion to stand develop film. I think
though the method I've suggested may
work very well. Dan

 

[sanking]

Easy, use a tray and separators. Liken a sheet of film
to a sheet of light weight RC paper. The method I suggest
is the same as the method I use to wash paper, long soaks.
The separators are of hydrophobic material, light weight
polyester batting.

Dan

Cradles or sloshers, which separte the film and have holes in the bottom to allow free flow of processing chemicals, work fine for developing film with minimal agitation methods. Photographer's Formulary sells one that someone in my class used last time I taught a workshop out there.

I personally prefer the tube method described earlier because with it most of the work can be done in the light. I am one of those persons who hates standing around in total darkness sloshing developer around.

Sandy King

 

[richard ide]

When you are stand developing film other than flat in a tray; is there not a danger of bromide drag?

 

[sanking]

When you are stand developing film other than flat in a tray; is there not a danger of bromide drag?

There is some risk of bromide drag with pure stand development (one agitation cycle at the beginning of development, and no more after that) regardless of whether the film is flat in a tray or standing in a tube or hanger. For this reason I avoid pure stand development and generally use minimal agitation, which is four agitation cycles, one at the beginning, then at the 1/4, 1/2 and 3/4 points of total development time.

Some are able to get good results with one agitation cycle at the beginning, and another at the half way ponint of development.

The developer is an important factor. Some clearly work much better with reduced agitation than others. Pyrogallol based developers, for example, oxidize rapidly and have a tendency to give uneven staining if there is too little agitation. Developers like Rodinal, HC-110, and Pyrocat seem to work fine with reduced agitation if the working solution is very dilute.

There is a lot more art than science in all of this, but some people, Steve Sherman for example, appear to have locked the essentials down pretty well.

Sandy King

 

[dancqu]

Cradles or sloshers, which separte the film and have holes
in the bottom to allow free flow of processing chemicals, work
fine for developing film with minimal agitation methods.

I personally prefer the tube method described earlier because
with it most of the work can be done in the light. I am one of
those persons who hates standing around in total darkness
sloshing developer around. Sandy King

"Cradles, sloshers, .... free flow of ... chemicals ... minimal
agitation ... " And I suppose Cradles and sloshers are used
with the lights on while providing true stand development?

A continuous totally dark darkroom is NOT needed using the
method I've suggested. Only the tray with film processing
need be covered. And there is NO "standing around ...
sloshing developer. The subject at this time is
STAND developing.

So, any one with $1.00 and two trays of proper size can
give the tray with separators method a try. For long
stands Horizontal may be better. Dan

 

[Steve Sherman]

Perception

I'll concede that acutance can be measured, but at the same time I stand by my original meaning of "perception" as it relates to the print and in the context I intended.

When looking at two prints side by side, perceptions are formed based on the information in front of the viewer. With prints made from negatives where Reduced Agitation Dev. was used most likely will give the perception of being sharper based on increased micro contrast.

Personally, the ability to measure acutance has less importance than the ability to enhance the perception of acutance when in the end all that matters (for most) is the final print and how it is perceived.

Further, I cannot discount any of the reasons discussed here to increase acutance.

However, I do believe the single biggest contributor to increasing acutance is micro contrast and in my experience micro contrast is controlled most significantly by developer exhaustion (dilution) and frequency of agitation.

So in the end, what is best about the Internet age is also its curse. Lord knows without the internet I would never have come across Sandy King’s near perfect Pyrocat Developer or his description of Stand Development and been moved to try some experimenting myself. The downside, illustrated here in this one thread is almost a dozen reasons why acutance is real from developers to tripods or films to agitations. For those who might not have the command of the photographic process as some are left to decipher what combinations discussed here to impliment so that their prints will look like XYZ’s.

I have been exchanging emails with another LF photog from another forum who is trying to gain a handle on all the subtleties of Reduced Agitation Dev. He has seen the rewards of the process but at the same time calls it a PITA, I couldn’t agree with him more!

Cheers

 

[gainer]

Let me remind you all that a paper safe with a hinged lid makes a good daylight developing tank for LF for either agitation by sloshing or stand development, especially when you're short of funds for such luxuries.

 

[Ian Grant]

However, I do believe the single biggest contributor to increasing acutance is micro contrast and in my experience micro contrast is controlled most significantly by developer exhaustion (dilution) and frequency of agitation.

That's putting the chicken before the egg

First the choice of developer is critical, as some will give a high degree of acutance at normal agitation, it's fair to say they virtually all rely on high dilution.

Secondly the degree of dilution and type of agitation can also be used to increase the acutance further, (which is your point).

But it's like comparing apples to oranges, Pyrocat HD gives good acutance at normal dilution (1+1+100) and typical normal agitation, but in comparison some of the high acutance developers give substantially greater acutance, quite noticeably so with normal agitation.

So there's not one cap tofit all. Remember that a high acutance developer which is too extreme for say 35mm may in fact be ideal for Large Format without the need for stand or semi-stand development. As they say there are many ways to skin a cat.

I'm not disagreeing with you Steve because what you do works as expected, but pointing out there's also a bigger overall picture.

Ian

 

[Peter De Smidt]

Having run a print exchange for years, I have a pretty big collection of prints, mainly 8x10 prints from 4x5 negatives, from a large number of photographers. Ralph took part in a number of exchanges, and his prints, which I think were from 120mm negatives, have the highest technical quality of any of the prints in my collection. Thus his understanding of the technical aspects of photography has clearly made a very positive impact in the quality of his prints.

 

[Steve Sherman]

That's putting the chicken before the egg

First the choice of developer is critical, as some will give a high degree of acutance at normal agitation, it's fair to say they virtually all rely on high dilution.

Secondly the degree of dilution and type of agitation can also be used to increase the acutance further, (which is your point).

But it's like comparing apples to oranges, Pyrocat HD gives good acutance at normal dilution (1+1+100) and typical normal agitation, but in comparison some of the high acutance developers give substantially greater acutance, quite noticeably so with normal agitation.

So there's not one cap tofit all. Remember that a high acutance developer which is too extreme for say 35mm may in fact be ideal for Large Format without the need for stand or semi-stand development. As they say there are many ways to skin a cat.

I'm not disagreeing with you Steve because what you do works as expected, but pointing out there's also a bigger overall picture.

Ian

Ian,

I really can't dispute your claim for the only developers I have ever used are PyroCat HD and PMK.

Going all the way back to what got me involved in this thread in the first place, the acutance component of the process is secondary to me.

The process allows one to control micro contrast to such a degree that the entire literal scene is significantly altered, a byproduct of that phenomenon is higher acutance through adjancey effects. Herein lies the creative possibilities of Reduced Agitation Dev.

For whatever reason very few choose to discuss those attributes of the process. Very likely the word "acutance" is what got me involved in the thread in the first place, hoping to launch a discussion in the direction of the possibilities beyond increased apparent sharpness.

If Peter is interested in sending me his address I will forward him a print shown here which was developed using the RA method and let a third party evaluate and report his perceptions.

Cheers

 

[sanking]

Going all the way back to what got me involved in this thread in the first place, the acutance component of the process is secondary to me.

For whatever reason very few choose to discuss those attributes of the process. Very likely the word "acutance" is what got me involved in the thread in the first place, hoping to launch a discussion in the direction of the possibilities beyond increased apparent sharpness.


Cheers

Steve,

The micro-contrast you get in your prints is a direct result of increased acutance. They are the same thing. Acutance/micro-contrast gives enhanced separation of local tonal values, and this increases apparent sharpness. I believe you are saying that the greater separation of close tonal values is more important to you than the apparent sharpness but I don't see how one separates the two since they are linked as your fingers to your hand.

Long development times with dilute developers also tends to give maximum shadow detail, and with some films may change the curve as well, generally giving it a longer straight line section. You can also do this with two-bath developers.


Sandy King

 

[Steve Sherman]

Steve,

The micro-contrast you get in your prints is a direct result of increased acutance. They are the same thing. Acutance/micro-contrast gives enhanced separation of local tonal values, and this increases apparent sharpness. I believe you are saying that the greater separation of close tonal values is more important to you than the apparent sharpness but I don't see how one separates the two since they are linked as your fingers to your hand.


Sandy King

Sandy, love the hand analogy, as a baseball coach I understand that the two most important fingers are the largest ones on the hand, having the most effect on what we can make the ball do. However, without the other three fingers the ball would fall out of ones hand.

I guess what I am driving at is this, speaking as it relates to my specific interests in photography.

If the only result of Reduced Agitation Dev. was merely to increased acutance and apparent sharpness there would be no way I would go thorough what is necessary to complete the process. Lord knows there are tradeoffs to the micro contrast gain that still trouble me and have never ever been discussed anywhere that I know of.

For my particular interests in B&W photography the ability to completely alter and plan for a significantly different rendering of a scene is paramount. Very basically, it has been said before but few understand the succietness of this phrase. Reduced Agitation Dev. maximizes film speed, maximizes shadow separation and compresses highlight density, ALL at the SAME TIME.

For someone who strives for texture in low and mid tones under extreme lighting conditions, whether it be flat light or harsh light this process is truly a magic bullet.

Back to baseball, my favorite quote of all time is “Baseball is like church, many attend, few understand.”

Love that quote, Cheers

 

[dancqu]

My findings on the formation of edge effects and a possible
reason for them:
www.apug.org/forums/forum37/45289-do-some-films-have-even-ness-additive.html

Is the following what you are saying in your first
post that thread?

On the negative a band of higher density was observed
on the light gray card where adjacent to the dark gray
card. Was the density greater than that of the
dark gray card? Dan

 

[Alan Johnson]

Dan,
They were just ordinary Mackie lines.My point was that they are more prominent on some older type emusions.Newer emulsions rely less on such edge effects ,they have a higher knife-edge acutance.

 

[sanking]

With good technique it is possible to get some excelelnt results from a medium speed B&W film. I am attaching a couple of files to show the kind of results I expect from a combination of Mamiya 7II and Fuji Acros. The original negative was made with the camera on a tripod, with the lens set to f/11. The film was developed in two-bath Pyrocat, 1:10, 6+6 at 75F. The negative was scanned with a dedicated film scanner at 5080 spi.

One of the files attached is the overall view, which has been reduced to 10" in width at 125 dpi. The other file corresponds to a crop of 0.15" of the 2.75" long dimension of the original scanned 6X7 cm negatie. The crop shows you what the print quality would look like if the original negative were enlarged to about 180" wide, or about 65X. Even at this huge size sharpness is very good and grain is almost non-existent. A print of 30X40" in size from this negative would rival, IMO, the best work one could expect from 4X5.

Sandy King

 

[Mahler_one]

SandY: Very impressive results. Makes one wonder if the 35mm format, using careful developing techniques, might enable one to make 8x10 enlargements that would be analogous to the results with 120 film at the putative 30x40 print size, i.e., could an enlargement of a 35mm frame offer the possibility of rivaling the results of an 8x10 enlargement of a 4x5 frame. Comments?

Ed

 

[Mahler_one]

By the way Sandy, is there a link to the two bath Pyrocat developing method? Have you ever compared "Pyrocat two bath" to one of the other developer/ film combinations that are said to yield negatives with a lower grain, e.g., The 20 ASA Adox film with the developer recommended for such film? One realizes of course that 20 ASA film does limit depth of field, etc., etc.

Ed

 

[Mahler_one]

Gainer: What a clever suggestion! I was thinking about dancqu's suggestions of covering a tray holding the developer and film with another bigger tray ( almost like sheet film is protected in the box ) in order to develop using slosher trays in the daylight.

Dancqu-what about temperature control ( see below as well )?

Gainer...doesn't the plastic paper safe leak? How do you make a go of controlling temperature over times required for minimal agitation? Does one simply place the paper safe into a larger tray with water at the required temperature? There must be some drift of temperature while the paper safe is in the water tray....is such temperature drift significant?

Finally: Don't completely forget about developing by inspection! I know that Michael and Paula are great supporters of DBI. Some have utilized IR devices to greatly simplify DBI. I guess one would do minimal agitation, and simply look at the negatives periodically until the highlights were developed to the extent one desired.

Ed

 

[sanking]

SandY: Very impressive results. Makes one wonder if the 35mm format, using careful developing techniques, might enable one to make 8x10 enlargements that would be analogous to the results with 120 film at the putative 30x40 print size, i.e., could an enlargement of a 35mm frame offer the possibility of rivaling the results of an 8x10 enlargement of a 4x5 frame. Comments?

Ed

I am sure that is possible. In fact, I have seen it with my own eyes. But to rival enlargments of 4X5 to 8X10 with 35mm requires not only very good technique and choice of film, but also very expensive camera and lens. But I have seen amazing results with Leica M7 with Summicron aspheric glass with high resolution film.

Sandy

 

[sanking]

By the way Sandy, is there a link to the two bath Pyrocat developing method? Have you ever compared "Pyrocat two bath" to one of the other developer/ film combinations that are said to yield negatives with a lower grain, e.g., The 20 ASA Adox film with the developer recommended for such film? One realizes of course that 20 ASA film does limit depth of field, etc., etc.

Ed

Yes, I have compared Rollei Pan 25 in several different developers, including the low contrast developer Rollei sells for the film, two-bath D23, Diafine, and two-bath Pyrocat. Two-bath D23 and two-bath Pyrocat both beat the Rollei developer, IMO. Between D23 and Pyrocat I get better grain with Pyrocat, and more sharpness with scanning.

Sandy King