Spur acurol-n

[leondf]

I had some questions about developer SPUR ACUROL-N

At spur-photo.com they present marketing info which says,

"At high dilutions, long developing times and reduced agitation, a distinct Eberhard
effect provides for maximum sharpness of contours and maximum plasticity"

The data sheet says,
"SPUR ACUROL-N responds far more easily to changes in agitation than conventional developers. It is therefore necessary to
adhere rather closely to the indicated inversion tact and developing times when using low dilutions (1+25 to 1+50). Otherwise the
lights turn out too steep, thereby impairing tonal values."
"The higher the dilution and the less agitation (e.g. stand development of 5 minutes), the more sculptural the image expression and
the more acutance (Eberhard effect)."

but it also says,
"The developing parameters indicated in the developing chart were determined using 35 mm films. With larger formats, and above
all high dilutions (1+100 or higher) you must increase agitation or prolong development. Rule of thumb: Agitate twice as much as
usual when developing roll film (i.e. invert twice instead of once) and thrice as much when developing sheet film (i.e. invert three
times instead of once). The reason for this is that due to the larger format, and especially with high dilutions, the capacity of the
working solution decreases more rapidly during inversion."

It has a chart that gives processing for Ilford HP5+ at a dillution of 1+100, 24 deg C "Inversion Tact - 30 sec permanently and once every 5 minutes thereafter", developing time 25.5 minutes

Maybe this is a translation issue but I assume "Tact" refers to protocol, and inversion means physical inversion of the developing tank. My LF negatives are processed on hangers in an open top tank. I see reference to the fact that the type of agitation is important. So, jiggling a hanger might not be equivalent to inverting a tank.

1. Does anyone have thoughts on what open tank agitation might correspond to one inversion?
2. How to understand "the capacity of the working solution decreases more rapidly during inversion."? Why would that imply you should agitate more? Are they simply saying, the developer needs to be mixed more, since its "capacity" or potency near the film is low?
3. A more basic question, is this a 1-shot developer, i.e., do you use it once and discard?

[Mark Sampson]

I'll guess that one round of "lift-and-tilt" agitation, as per Kodak's instructions, should equal one round of tank inversions. And based on other highly-diluted developers I've used, I'll also suggest that any developer diluted 1:25 or 1:50 is a one-shot.
You've got some experimenting to do. Take good notes and share your results!

[leondf]

I'll guess that one round of "lift-and-tilt" agitation, as per Kodak's instructions, should equal one round of tank inversions. And based on other highly-diluted developers I've used, I'll also suggest that any developer diluted 1:25 or 1:50 is a one-shot.
You've got some experimenting to do. Take good notes and share your results!

Thanks Mark. So, lift and tilt means lift the holder completely out of the tank, tilt it to drain a little and re-immerse? Apparently I would do this 3 times in a row at each 5 minute mark. The one-shot part seems wasteful since I'll have a whole tank of this stuff, about 2 gallons. I have ordered some, I'll let you know what happens.

[Doremus Scudder]

Your instructions appear to be a bad translation from German or one of the Germanic languages.

Here are some observations that might help:

The Eberhard effect produces Mackie lines; two fine adjacent lines, one with increased, the other decreased, density between larger areas of different overall densities. This is caused by developer exhaustion in the higher density area and the resulting by-products, which restrain development (bromides). These by-products bleed over into the adjacent area, restraining development there somewhat and causing a fine line of reduced density. At the same time active developer from the less dense area bleeds back into the higher density area causing a fine line of more density. The result is an outlining effect that increases visual sharpness and gives a "drawn" look to the rendering. The reference to "plasticity" in the instructions refers to this sculpted effect (Plastik = sculpture in German). Note that the Eberhard effect can only occur if the developer is exhausting in high-density areas before another agitation happens, and so requires reduced agitations and higher developer dilutions to occur.

The word "Takt" in German means "interval." I'm sure this is what they mean when the use the word "tact." Just replace it with "interval" and you'll be fine.

Their discussion on agitation intervals seems a bit sketchy though. I doubt that sheet film really needs more agitation to achieve a particular effect than smaller film. However, sheet film is often more prone to uneven development because of the size of the tank/tray/whatever, so they may be referring to increasing agitation intervals, especially at the beginning of development to ensure evenness.

"... the light turns out too steep..." = "... the highlights turn out too dense..."

"... the capacity of the working solution decreases more rapidly during inversion." This makes no sense in any photo-chemistry world I know if the developer volume is matched to area of film being developed. However, they may be assuming that larger film will be developed with less developer per unit of area, in which case the developer would, indeed, be exhausted faster. Normal admonitions for using enough stock volume for the amount of film being developed apply.

"Inversion Tact - 30 sec permanently and once every 5 minutes thereafter" = "Agitation intervals - 30 seconds continuous agitation to start and one agitation every 5 minutes thereafter." (Note, I'm replacing "inversion" with "agitation," since you don't use inversion agitation.)

Since you develop in tanks with hangers (which they don't address at all), just use your normal agitation method, reducing intervals after the initial agitation to achieve the Eberhard effect if you want. I doubt you will run out of capacity with the large tanks. Still, if you find that your negatives are denser when you just do a few in the full tank as opposed to when you do a full run, I'd maybe standardize on fewer sheets per batch or change dilution. You'll have to test. I assume you lift the hangers out, tip and re-submerge twice for an agitation (lift-tilt one direction-submerge-lift-tilt the other direction-submerge is a standard agitation for hangers and tanks). This would be your "inversion." Still, if you've had good luck with other developers doing what you do, then just apply that to this developer adjusting your agitation intervals to appropriately reduce the interval per their instructions to start.

This is almost certainly a one-shot developer, since it is used in very weak dilution and designed to exhaust in order to create edge effects. You can test a second batch through the developer to see, but don't use good negatives!

Hope this helps,

Doremus

[Mark Sampson]

Mr. Scudder is, as usual, knowledgable, thoughtful and sensible about darkroom practice. His advice is an articulate explanation of some concepts I couldn't quite put into words... in German or English.
BTW, Kodak's method of agitating sheet film in hangers and deep tanks is explained in their publication "Photography with Large-format Cameras"... which you can find on the used market. I was trained on that method in my first job, in the late '70s, and used it for some years. Best of luck!

[leondf]

Your instructions appear to be a bad translation from German or one of the Germanic languages.
...

Doremus

Doremus, Thank you for your informative reply. With your help, I now have a much better understanding of the Eberhard effect. Your interpretation of the translation is very helpful. I have been using Bergger Pancro 400 developed in Xtol. To increase negative density I have tried shooting at ASA 200 and increasing development time. But the change in density is minimal and the images seem somewhat flat, even with printing at a high grade. After reading a review, I thought I'd try Spur acrol-n. I am in the US and I ordered it in Germany, so I must wait for it to arrive. Thank you again.

[leondf]

Mark, thank you for the reference. I will look for "Photography with Large-format Cameras". I have a copy of Stroebel's "View Camera Technique" which I purchased years ago. I went back and looked at it. It does mention the technique you refer to. I should have thought to check it. Thanks.

[Alan9940]

I have used this developer for years, for roll film, though, following the recommendations contained herein:

https://www.fotoskoda.cz/images/contentpics/temna_komora/Spur_Acurol_N_Data-Sheet.pdf

I don't see any reason why it couldn't be used to develop LF film in tanks & hangers following Doremus's excellent advice. FWIW, if you like this developer and plan to continue using it, you can order it direct from schain@spur-photo.de. I'm in the US, too, and he has always been fair with shipping cost.

[leondf]

Alan,

Thank you for your information. I have sent an email, inquiring about the price of Spur Acurol-N and shipping fees.

Leon

[leondf]

I thought I'd present the results of my research into buying Spur acurol-n in Germany. The shipping fee is for shipping to Massachusetts, USA.

SPUR Acurol N 250 ml - 1 bottle

fotoimpex.de
17,65 EUR
The net shipping charges are: 35,00 EUR

spur-photo.de
€ 21,
shipping is € 21,50 for orders up to a weight of 2 kg.

macodirect.de
17,65EUR
21.85 EUR shipping

Apparently the shipping cost is the same for up to 2 kg, so it would be more economical to buy several bottles at once.
There is some question of whether or not macrodirect has the item in stock.

[Alan9940]

Apparently the shipping cost is the same for up to 2 kg, so it would be more economical to buy several bottles at once.


As stated above, I always buy direct and buy 2 - 4 bottles at a time. The stuff lasts for quite awhile; not like Rodinal or HC-110, of course, but long enough for me to use up most of it.

[leondf]

My order of Spur Acurol-N arrived. It took about 3 weeks. I'm shooting 11x14 Bergger Pancro 400 at ASA 200. The developer comes with literature that recommends dilution of 1+35 and developing time of 13 minutes with "inversion" (agitation) twice each minute with a resultant "soft" contrast. They say contrast can be increased by either increasing agitation of lengthening the development time. For sheet film, an inversion apparently consists of lifting the film out of the tank, tilting to one side, returning to the tank, then repeating, tilting to the other side. For sheet film, each agitation consists of 3 inversions (so, 6 per minute). In practice it took me 20 sec or longer to complete one agitation cycle, so 2 cycles meant essentially, continuous agitation. I decided to drop to one cycle per minute and increase development time a bit to compensate for less agitation. When you shoot at lower ASA the required development time or developer concentration drops somewhat. I have read that people who shoot at ASA 200 use dilution 1+50 for 13 minutes. I appreciated the YouTube video, "Bergger Pancro 400 - The Ultimate Film Review" by Analog insights. I was a little concerned about "soft" contrast. My developing tank holds 10 liters, the developer comes in 250ml bottles. So I mixed the contents of 1 bottle into my tank for approx. 1+40 dilution and developed for 16 minutes. In retrospect, 1+50 for 13 minutes would probably be fine. I shot some portraits indoors using flash, not the typical use of Spur Acurol-N, which is recommended for high resolution, detail work. I was intrigued by the "high acutance". I very much like the results. The negatives appear to have correct density and the resulting prints are beautiful. I intend to shoot more and try some extended development time at higher dilution. Jules Bobach at Analog Insights cautioned that for large format use, Spur Acurol-N stand development might result in uneven development and bromide drag. I'll let you know what happens.

[leondf]

I couldn't find info on the capacity of Spur Acurol-N. For my first try I decided to process 6 11x14 sheets, 2 at a time. That worked out fine. I suspect the capacity is considerably higher. As I started my last pair of sheets, I apparently lost concentration and put the sheets in the tank with photo-flo instead of the presoak tank. When I realized my error I rinsed the film and continued. This time instead of putting the film in the developer, I put it in the tank with stop. I assumed the film was ruined but I rinsed it off and developed it. To my surprise the negatives looked fine, perhaps a little less dense than the others.