Acutance & Enlargement: Uncomfortable Bedfellows?

[Sparky]

I've got a pile of FP4 I was going to develop in my standard Perceptol 1:4 bath. However - I was thinking that, since I'd earmarked these negs (if they work out as intended) for huge enlargement (approx. 10x) - I was wondering if acutance wouldn't look weird at that size. Has anyone else developed at high dilution and done an extreme enlargement?

(note to self: maybe the result wouldn't be so different from printing a 16x20 from 120 format... perhaps)

 

[patrickjames]

I am not familiar with perceptol, but if you want greater enlargement, acutance is a must. Solvent developers tend to look horrible when enlarged to a great degree (opinion) since they are so soft. I use Rodinal for the most part and I never have any problems with huge enlargements because when the grain looks sharp the print looks sharp. Hope this helps.

Patrick

 

[Tom Stanworth]

I am not familiar with perceptol, but if you want greater enlargement, acutance is a must. Solvent developers tend to look horrible when enlarged to a great degree (opinion) since they are so soft. I use Rodinal for the most part and I never have any problems with huge enlargements because when the grain looks sharp the print looks sharp. Hope this helps.

Patrick

I agree in part, but so can acutance devs 'have issues with big prints as tonality is destroyed with big enlargements. I personally like acutance devs where the film is enlarged, say 3-4 times max. Above that a std developer is perhaps preferable, but it depends on the subject: IS this a creamy fog scene which must have tonality or a gritty street/docu scene where crispness is the emphasis required?

I have never used perceptol 1+4, only 1+1 and 1+2. I would also say that at 1+2 at least, this dev produces reasonable acutance but is not in any way a true acutance dev. I did side to side comparison with Pyrocat Hd/Exactol Lux and the difference in a 5x4 printed to 20x16 was very clear, the perceptol was far mushier.

I would say that if you know perceptol 1+4 like the back of your hand then this should be teh deciding factor. For a 10X tho, I would be tempted to go for a less diluted brew (assuming 1+4 is an appreciably less fine grained dev than 1+2)

 

[Sparky]

Ilford normally recommends 1:2 (1+1) and 1:4 (1+3). I think dilute perceptol is phenomenal for smaller prints... so I was concerned the detail might fall apart a little bit with the relative lack of grain structure. But on the other hand something like a pyro might be bad due to it's EMPHASIS of grain - also a no-no for me for a big print. But I guess the enlargement just forces me to find the perfect tradeoff...!

 

[gainer]

You could examine a small print with a magnifying glass to get an idea of what a larger print will look like. Enlarging will not amplify the evidence of accutance any more than it does the rest of the photo. The comfortable viewing distance is usually equal to the diagonal of the print.

Acutance means sharpness in the public English language. In photo lingo it is often taken to apply only to the artificial edge effect that makes edges look sharper by distorting the local gradient so that there is a lower than true density on the light side of a boundary and a higher than true density on the dark side. The human eye provides its own edge effect as you can see by viewing a dark knife edge against a paper white background.

A simple ascorbate developer with little or no sulfite can produce sharp boundaries where they exist in the image that fell on the film without exaggerating the acutance. PC-TEA is an example. But it is not only the developer, but also the method and amount of agitation that figures in. You know the importance of using sharp lenses at their optimum apertures in architectural photography. It seems to me that you ought to do some test shots and vary the development from embellished acutance to the truest image you can get in order to see which suits you best. So, I can't give you a direct answer, but I can point out some factors that will go into the answer. Maybe.

 

[Sparky]

Yes - I thought perhaps the illusion of sharpness might fall apart at extreme magnifications - at which point - maybe it's better to rely upon a well-defined grain structure... but we'll just hafta see.

 

[Ryuji]

Accutance is enlarged together with the image and the grain, so you need less accutance when making large enlargements. FP4 Plus is perfectly capable of very nice 10x enlargement if developed in DS-10 stock or 1+1, or XTOL stock. Perceptol is not a bad choice, but I prefer the tonality and visual sharpness of DS-10 better.

 

[Tom Hoskinson]

Ilford normally recommends 1:2 (1+1) and 1:4 (1+3). I think dilute perceptol is phenomenal for smaller prints... so I was concerned the detail might fall apart a little bit with the relative lack of grain structure. But on the other hand something like a pyro might be bad due to it's EMPHASIS of grain - also a no-no for me for a big print. But I guess the enlargement just forces me to find the perfect tradeoff...!

Pyro developers don't emphasize grain - the stain tends to mask the grain.