need better reciprocity characteristics

[Bruce Watson]

I've just spent a week and a half in the NC mountains shooting in dark overcast conditions. Reciprocity correction was SOP. If I'm going to keep doing stuff like this, I need films that are built for it. I'm not talking about night photography here - but dark overcast in the woods seems to come close sometimes.

What 5x4 negative films (not transparency), color and B&W, have good reciprocity characteristics? Anything out there that can take a 10 second exposure as metered? For example, I read that 100Tmax has good reciprocity characteristics, but I hear that Acros is even better. Do any of you who use these films have experience that supports or contradicts the manufacturer's hype?

So, you low light fanatics - what do you use and how do you like it for those somewhat longer than usual exposures?

[robc]

Fuji acros has upto 2 mins before reciprocity kicks in.
Fuji Provia RDPIII also has upto 2 mins but its transparency
don't know about colour neg films

Ilford HP5 starts at anything over 1 sec but I have found the reciprocity chart for HP5 to be accurate when making adjustments for reciprocity but you should base exposure on a highlight value for it to work best.

bearing in mind that hp5 is a good 2 stops faster than fuji acros then what was a 10 sec metered exposure for a 100 speed film would only be around 2.5 secs on hp5 which is only just bordering on going into reciprocity and no adjustment should be necessary if you have calibrated exposure and dev accurately for it.

[Ron Marshall]

Acros and Astia (transparency) both do not need any correction for times less than 2 minutes. For color negative I think the new 160 pro (real speed 100 ASA) does not need correction until 2 or 4 seconds (can't remember which).

[Oren Grad]

Best reciprocity performance among slow films that I've used is probably Delta 100, though TMX is pretty good too. Afraid I have no experience with Acros, though. Best reciprocity performance among fast films is TMY, by a fair margin.

That said, I use HP5 Plus, because I prefer its characteristics overall. Its reciprocity characteristics are decent - better than TXP or the eastern European films, though not so good as TMY. It's workable in the fast-fading light at dusk, where slower films are a real problem. I'm eagerly awaiting the slow boat from England with my order of HP5 Plus in odd sizes, so I can get away from the FP4 Plus and Fortepan stock I'm still using in some of these sizes.

But if you're having severe reciprocity problems and don't mind the curve shape and the somewhat narrower latitude in exposure and processing of TMY, that may be your best place to start in looking for an alternative.

BTW, at least in my experience, I haven't seen any B&W film that can take a 10 second exposure as metered. But 100 Delta, TMX and TMY don't "fall off the cliff" nearly so abruptly as most other films.

[Ed K.]

Acros for B&W, and Provia / other Fuji slide films for long exposures. The neg films I like all have quite a bit of reciprocity, I don't personally use them for long exposures. If you can use a roll film back, you might have a few more options. Note that Acros B&W will push a stop nicely+ when needed without much grain, however since it's contrasty stuff to begin with, I often end up pulling it for "normal" situations.

To view more detailed information on all of Fuji's offerings at least, you can check out their full manual and datasheet. It lists their slide and neg films reciprocity all within two pages or so:

Fujifilm USA Professional Film Data Guide ("http://www.fujifilmusa.com/JSP/fuji/epartners/bin/ProfessionalFilmDataGuide.pdf" target=_blank)

Kodak has data sheets too.

[John Kasaian]

For B&W I like Tmax 400. I've used it for nocturnal photography and its become my favorite.

[Ken Lee]

"Reciprocity correction was SOP".



SOP ?

[David Karp]

Standard Operating Procedure.

[Henry Ambrose]

NPS works well at long exposures. I suspect the new version will too. If I meter 10 seconds I'd shoot one at 10 and another at 20 to have a choice later on. Rate it at 100. The new version 160S (I think that's the right name) should work similarly.

For HP5 (and for some strange reason most other Ilford films) the corrections are:

metered > actual

5s > 10s

10s > 30s

15s > 60s

20s > 80s

25s > 120s

30s > 150s

35s > 200s

or (metered) exp. 1.48
(I have no idea how to write that correctly)

I use the chart.

[Oren Grad]

At least for the B&W films, the manufacturers' specifications for reciprocity correction can't always be taken at face value. There was a nice article in Photo Techniques a few years back in which Howard Bond reported reciprocity corrections for several films based on his own tests, and they differed substantially from the official recommendations. Might be worth tracking down to help in your choice.

[Brian Ellis]

T Max 100 has the best of the films I've used. John Sexton has published times for 100 and 400 based on his tests. In general they're about 25% better than non-T Max films . IIRC the first adjustment with T Max 100 using John's times is at 4 seconds.

[Wilbur Wong]

I shoot Portra 160VC exclusively. Kodak states there is no adjustments for reciprocity for the entire famiy of Portra films for exposures up to 10 seconds. After that they only recommend you make tests under your own conditions.

[John Brownlow]

A second vote for Portra. I shoot both 160NC and 400NC and I use a half stop extra between 1s and 10s, and a stop from 10s to 20s. Anything longer than that and I go home. I tend to expose the 160 at ISO 100 and the 400 at 320 or so.

The behavior of these films in every respect including reciprocity is exemplary. It's very hard for me to think of ways they could be improved.

[Michael Heald]

Hello! I tested TMax 400 for astrophotography. Out to 16 minutes, it lost 2 1/2 stops. Best regards.

Mike