On Acutance?

Although I've never used Dixactol, PMK is really nice with 400-speed films like Tri-X and HP5 Plus, and probably others.

Stoo, Thank you. All info is helpful to one who is ignorant! This is the sort of tidbit that can save me time and wasted energy, what doesn't work is as useful to know as what does. I'm open to other developers and films as has been suggested above, I was mostly interested in exploring the whole grain edge effect, and I was only recently introduced to the concept--I'm a noob when it comes to chemistry really--we are lucky enough to have some fine thinkers and experimenters on this board. With a near infinite variety of film, developers and printing combinations out there (even the paper), I defer to those more experienced and am grateful for aiming me in more promising directions.

c6h6o3--It was in some other thread on this board that a few people suggested less agitation with the Neo 400. I did the first three rolls by the book, with the five rather brisk inversions in five seconds per 30 sec. etc and things seemed to lack contrast and be rather flat. The forth roll I changed the agitation to one minute, and fewer and gentler inversions, all else was equal. Not so sure about the accutance per se, but the negatives appear to have more contrast and a wider range of mid-tones, and the grain appeared smaller and 'tighter' or brighter, viewed thru the grain focuser. I think the few prints I've done from that fourth roll print better, just have more snap and range of color.

PhotoJim, I'm weighing PMK, Pyrocat HD, possibly Perceptol as well for my further experiments.

If I can't learn at least one new thing every day of my life, there's no point in getting out of bed, or waking up breathing for that matter!

I'm not wedded to the Neo 400 and am open to trying other films, as have been recommended. I just got a good deal on the 400.

Surprising that in a thread about acutance no one mentioned the importance of type of development until now. Depending on strength of dilution and type of agitation the image characteristics produced by developers such as PMK, Pyrocat-HD, Rodinal, etc. are remarkably different. Acutance, which is determined by micro-contrast and edge effects, will be entirely different for a negative developed in a very strong solution of one of these developers for a short period of time with continuous agitation than for a negative developed in a weak solution for a long time with minimal agitation.

Also, it should be noted that the degree of magnification plays a large role in determining how much acutance is desirable. 35mm negatives, which will typically be enlarged 10X and more, need a lot less acutance than LF negatives that will be enlarged 2X-4X.

Sandy King

c6h6o3 said:

Minimal agitation development also increases accutance dramatically.

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At the most basic level, the film you choose makes the biggest difference in the final look of the image in all respects, including sharpness. Then your developer will help you inch an extra 10% in the right direction.

It's silly to pick Delta 3200 and slave at making it sharp by using Rodinal or any other potential magic bullet. Take Delta 100, and it's sharp, (and I mean SHARP) even when developed in coffee and orange juice. With the pulp.

Of course the lenses used in exposure and printing matter, but for most practical purposes, any lens produced after WWII with more than three elements from a major manufacturer will give good results.

The reality is a little more complex, and someone can always prove that a higher enlargement of a 50-speed film developed in an acutance developer is sharper than a smaller enlargement from a 400-speed film developed in D-76, but instead of making comparisons of test chart, you should understand the principles and see how they apply to your work.

Thornton explains most of what there is to understand about sharpness in Edge of Darkness, so grab a few ideas from the book and go out shooting!

I have been surprised how sharp FP-4+ is when souped in XTOL 1:1.
You must use a tripod or shutter speed of 1/250 but no less than 1/125 if your goal is accutance.

I am shocked how a mint 1956 collapsible 50mm Summicron draws using this film/developer combo.

Most of the visible accutance directly relates to the film. ISO 400 films will not get you there.

XTOL allows you to use dilutions of 1:2 and 1:3. 1:3 is very sharp in the class of Rodinal without the grain. XTOL exceeds D-76 in sharpness and all-around image quality.

The Film Developing Cookbook is a must read.

Richard,
I am afraid I have to disagree with you . I did careful film clip trials with 35mm FP4 and HP5 using Xtol at 1+1 and 1+2, ID11 at 1+3 and Barry Thornton's one time favourite Perceptol 1+3.

Some of of the things I found were

1 FP4 looked no sharper than HP5

2 Differences in sharpness were marginal but ID11 1+3 was sharpest

3 Xtol had the finest grain but the other two had barely noticable grain either, on an 11 x 7 inch print.

4 ID11 1+3 yielded negatives that printed most easily.

5 Prints from the ID11 1+3 negatives had the most pleasing tonal disposition (I photographed the same subject for all the tests)

To put this acutance debate into perspective, points 1 to 3 are important when scrutinising a print. But from a normal viewing distance these subtle differences can't be seen, and point 5 becomes far more important.

I am happy to concede that "pleasing tonal" qualities are purely subjective, and that with practice I could probably get Xtol and perceptol to do what I wanted them to in this respect. To reiterate a point I made earlier in this thread there are numerous ways to get good results here.

Mike, experimenting with different films and developers is great fun, but there is a simpler way to achieve the biting sharpnes and crisp detail that you want. Get yourself a 5 x 4 camera! Then you really will see the biting sharpness and clarity of detail at normal viewing distances.

Alan Clark

ahhhh Alan,
The siren song, leading me down the road to ruin! Here I am starting to tentatively explore the options in used MF gear, and you're pushing me over the cliff to LF! Hahahaha! It was said by somebody on this forum that MF is a 'gateway drug' to LF, perhaps I should just make the leap and avoid the inter'medium' step! Sadly, at the moment my tiny darkroom space and equipment, the 35mm gear I have and my finances force me to explore the 'little' format more before answering the siren's call. I did explore a website that came up in another thread about making my own field camera tho...the seed has been planted.

Once again, thanx all for this ongoing discussion, much useful info and food for thought.

Mike Keers said:

.... and you're pushing me over the cliff to LF! ....

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Don't wimp out, start with a 20 x 24 camera.

Mike,
Lack of money, space and time are not acceptible excuses! When I realised that I could no longer live without a 5 x 4 camera I just set to and made one, despite being a very busy self-employed musical instrument maker. I also made a 5 x 4 enlarger. Actually just the head, which I designed to be interchangeable with my Meopta Opemus 6 enlarger head. My darkroom was tiny and there was no room for a second enlarger.
So roll up your sleeves and make a start!
And if you need any help just ask.

Alan Clark

Ahhh Alan, you really do come from the dark side (CBG! Is that centimeters or inches? LOL!). You're hitting below the belt as I'm a professional woodworker too (furniture) and inveterate tinkerer, have a well equipped shop, time on my hands and I know from what I've seen on the web I could easily make a field camera if I understood more about the shutter and film backs and so forth (and I suppose I could cobble most of an enlarger too, sigh). But then that's what the LF forum on here is for, to answer those questions, right? Ahhhhh, yooz guys.... Sorry for the thread drift in my own thread!

I tried large format several times. I found medium format was easier to deal with and provided the image quality I was after.

Concerning XTOL: I use both D-76 and XTOL and find the grain is tighter with XTOL. Kodak mentions XTOL will enlarge 10% more with equal quality vs D-76. I shot HP-5 once or twice and recall it has visible edge sharpness but larger grain. It makes sense increased grain would get in the way of high resolution.

I remember a series of articles many, many years ago (mid 50s) in one of the popular magazines (Modern Photography, I think) that discussed the tradeoffs of grain, sharpness, and overall quality over all the then popular films and developers. This was as the "thin emulsions" were just beginning to appear. As now, the film was the main determiner of grain and sharpness, but for any given film, the results could be very different for the various developers.An interesting point was that the rankings of each developer for grain or sharpness were pretty much the same across all the films; That is, the best developer for any quality was the best for all the films, and the worst was the worst for all films. Also, for the best developers, the tradeoffs between grain, sharpness, and overall quality were minor. The special acutance developers (e.g. FR X-22) did give a bit better sharpness, and fine grain developers (e.g. Microdol) did soften grain and decrease sharpness, but good developers were good in all respects, with an emphasis on their special qualities. Interesting to note is that D-76 (undiluted) ranked near the top in all categories and best overall in this very old evaluation.

acutance and resolution are not the same thing and it is important to understand this. finer grained films frequently lack acutance, or bite, Tmax 100 being notoriously bad and Delta 100 being relatively good in this regard. I find Xtol 1+2 just bearably crisp with MF 100 speed films enlarged up to 20x16 with a diffuser. Were I to use a condensor I am sure it would provide FAR more visual bite. However, for me, even with 400 speed films Xtol 1+2 is not providing the crisp visible tight grain I want and after experimenting with FX-39 mixed with Xtol, I am now trying Rodinal. I was skeptical, but at first glance the results are pretty darned good. problem is there is very little providing the very full speed of DDX/Xtol but with more bite. I find these two devs waaaaaay to smooth with some films and Rodinal alone too crunchy. The mix is looking nice. This is no magic bullet thing as I happily use DDX/Xtol but I am after a particular look along with full speed and these extra-curricular trials seem to be delivering. FX-39 mixed with Xtol was kinda interesting too, but the highly concentrated Rodinal is more economical as an additive (!!) and seems to produce the same overall end result which is to crispen up the grain noticeably. Film speed seems to be the same as Xtol 1+2, but the grain is very noticeably crunchier. I want barely visible, tight, hard grain in 20x16-20x24 prints from 6x7 400 speed films. Xtol wont give me that, but with 35mm Delta 100 is is very nice.

everyone's film, dev, lens, enlarger, enlargement size combo is different. Person A and Person B cannot compare unless they know whch print sizes they are talking about and who is using whch type of enlarger. One might be enlarging Hp5+ to 16x12 on a condesor with Xtol and the other to 10x8 with a colour head. The difference is night and day. 35mm delta 100 at 20x16 with my 10x8 colour head shows tiny, tight, crisp grain. At 10x8 it is creamy and shows none at all.

The Zone VI combation

I'm reading Fed pickers" Zone VI work book: in it Picker says after learning that Ansel Adams used TriX and HC110 exclusivly, he he confirmed this combination and is (was) also and exclusive user of it. There have been two changes since then Xtol which Kodak rates as slightly superior to HC 110, and a change in TrX.
Jay

Films I found to work well to produce edge effects are Adox/Efke 25,50,100;Plus-X,Tri-X,HP5. I found no edge effect at all with T-max 100.Developers in decreasing order of edge effect:FX-1, FX-2, dilute Rodinal,Pyrocat-HD, PC-TEA, all with reduced agitation and extended development.
Attachment is an example of 35mm Adox 50 developed in FX-1 27 min 68F agitated every 3 min.A light line can be seen at the top of the building,IMO this gives more of a 3-D appearance.
The effect is most easily seen by darkening highlights and increasing contrast but is visible on silver prints by making them slightly dark and high contrast.

Alan Johnson said:

Films I found to work well to produce edge effects are Adox/Efke 25,50,100;Plus-X,Tri-X,HP5. I found no edge effect at all with T-max 100.Developers in decreasing order of edge effect:FX-1, FX-2, dilute Rodinal,Pyrocat-HD, PC-TEA, all with reduced agitation and extended development.
Attachment is an example of 35mm Adox 50 developed in FX-1 27 min 68F agitated every 3 min.A light line can be seen at the top of the building,IMO this gives more of a 3-D appearance.
The effect is most easily seen by darkening highlights and increasing contrast but is visible on silver prints by making them slightly dark and high contrast.

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Not sure there is a delicate way to put this, but that photo looks much like what setting the "unsharp mask" tool to maximum on a certain computer-based manipulation application does. To my eyes, that photo just looks "digitally doctored", even though it isn't.

Tom,
Negative size makes the biggest difference, and you left this off your list.

Mike Keers,
Have you made that 5 x 4 camera yet?!

Alan Clark

accozzaglia said:

Not sure there is a delicate way to put this, but that photo looks much like what setting the "unsharp mask" tool to maximum on a certain computer-based manipulation application does. To my eyes, that photo just looks "digitally doctored", even though it isn't.

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This may be off limits for debate here so I will just say that the film process, which looks better to me, is visibly different from unsharp mask in that USM produces a corresponding black line opposite the light line on the print, whilst the film process does this to much less extent.Mackie first noted these lines from film in 1908.

The sharpest photo I have ever taken was on Adox CHS25 4x5" through a 90mm Rodenstock Grandagon N, and stand developed in 1+200 Rodinal for an hour and a half. It is crazy sharp.

Pity the composition is up to sh**, but hey, can't have everything...

There can be a big difference between looking at reproductions of photographs in a book like Barry Thornton's "Edge of Darkness" and looking at the photographs themselves. The impression of edge sharpness is a variable that lends itself to many controls in the printing industry. Plate setting, ink choice, paper characteristics, allowance for dot gain, et cetera, allow for more "acutance" or more "smoothness".

I was reminded of this when I compared a famous Ansel Adams photograph "Tenaya Creek, Dogwood, Rain. Yosemite National Park, 1948" with its reproduction in my copy of "Examples, The Making of Forty Photographs". The reproduction crackles with apparent sharpness, detail, and acutance while the original (in the vaults of the National Gallery of Australia) is something else again. The original museum size photograph emphasises tone, gradation, luminosity, and atmosphere. All the details are there too but they are merely an element contributing to the grandeur of the scene.

While the book reproduction cannot convey the presence of the original photograph it can deliver acutance. In this way looking at the photograph and looking at the book are both gratifying experiences but not equivalent or interchangeable.

Hi gang,
I'm still following the thread with interest, just haven't had anything to contribute.

Alan C...nope, no 5x4 camera yet, but I did score a very nice Rolleicord III a week ago on eBay, so I'm creeping up on larger negative sizes--haha! I only ran one roll of old obsolete color film thru that was in the camera (probably for about 20 years)--no point in developing it really. I ordered some 120 B&W film tho. But now the camera needs a CLA, the shutter has started to hang on the 1 second time--but not before I blow off a few rolls first, the higher speeds seem correct, or close enough. I also got a 'new' Omega B8 enlarger, so I'm close to doing some MF. Too many cameras, too little time.

Hello Mike,
Here is a possible cure for the sticking shutter. If you can get to the metal shutter blades, lubricate them with lighter fuel, painted on with a small brush. Then fire the shutter a few times.

Alan Clark

AlanC said:

Tom,
Negative size makes the biggest difference, and you left this off your list.

Mike Keers,
Have you made that 5 x 4 camera yet?!

Alan Clark

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Absolutely, but its the same issue as the enlargement factor. Bigger negs tends to be enlarged less, but if enlarged to the same extent the effect is the same. Getting the balance is the tough one. Perfect acutance for a 4x enlargement might not look so hot if enlarged 10x or vica versa. I tend to go for something inbetween, tho I am aiming to generate grain with some 35mm work at the moment; not straight rodinal (too much with 35mm TriX for what I want) but mixed with Xtol its looking kinda nice....

Hello Tom,
I agree, there are no easy "fits all" options are they? Non-photographers don't realise what problems we have!
I am fully in tune with your comments about trying to get just the right degree of grain into 35mm prints, though this in itself varies according to print size, as you say. I quite like HP5+ in rodinal for 35mm landscapes, but for other subjects I find the grain gets in the way of the subject. So for a farm study I'm doing I develop HP5 in ID11 1+3.
Just started trying 35mm Delta 100 in Rodinal and contrary to expectations this does have a bit of grain and grit.-I thought it would be too smooth. It is also very sharp.

Alan Clark

Mike Keers said:

Hi gang,
I'm still following the thread with interest, just haven't had anything to contribute.

Alan C...nope, no 5x4 camera yet, but I did score a very nice Rolleicord III a week ago on eBay, so I'm creeping up on larger negative sizes--haha! I only ran one roll of old obsolete color film thru that was in the camera (probably for about 20 years)--no point in developing it really. I ordered some 120 B&W film tho. But now the camera needs a CLA, the shutter has started to hang on the 1 second time--but not before I blow off a few rolls first, the higher speeds seem correct, or close enough. I also got a 'new' Omega B8 enlarger, so I'm close to doing some MF. Too many cameras, too little time.

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When the shutter hangs on the speeds longer than 1/25, it is usually the clockwork-like delay, not the shutter blades. You may be able to find a place to clean out the gear works with the lighter fluid and lubricate with a little clock oil. It may be only a lever at the end of the gear train that is sticking, one that does not come into play at the fast speeds.