Ilford - new reciprocity failure compensation factors

[Drew Wiley]

That's helpful. These films differ with regard to shadow placement, but nominal Z2 usually works for FP4, a film I use often enough to be correct with long exp thru sheer experience. But another thing which needs to be differentiated is night exposures which probably don't involve filtrstion, and long daylight exp due to a combo of dense contrast filters and small f-stops. Deep blue filters significantly depress the gamma of most films at long exp and require longer or plus dev. Red and green can differ in this respect between different films. Only Kodak TMax films were engineered with symmetry in this respect, though TMY needs a bit of tweaking for green as I recall (the actual plots are in the lab). Most people don't carry deep blue filters, but I'm tempted to throw one in the pack today.

[Pere Casals]

Another factor is film toe, the now defunct LF Acros had excellent LIRF factors, but it was short toe, while TXP is longer toe. This may be important in some situations.

Another think to consider at night is EMA...

[Drew Wiley]

Both TMax have very short toe, less than FP4 or TX. Pity the only "straight line" left on the market is Fomapan 200, which has horrible long exp characteristics. Wish ole Super XX were still around, or even Bergger 200.

[David Karp]

OK, so now I am thinking about it some more. After reading Doremus's post and thinking about my photography, ignoring where zones fall does not make sense. It may be that there is nothing we can do about it (except perhaps adjust development), but the zones have to fall somewhere based on what decisions we make when metering. If I absolutely place an important zone that absolutely has to look a certain way in my final photo, then there are consequences. Things are going to go darker higher up the scale than if I placed that part of the scene lower. Of course, we normally meter to ensure adequate detail in the shadows, but sometimes make judgments about what to sacrifice based on the needs of the desired photo. Not worrying about zone placement would imply that we just take an incident reading or place zones based on keeping zone 1 2/3 at .1 above Fb+fog.

As I keep thinking around this, I am back wondering if I can follow my normal procedures for low light landscapes or whether I need to make an adjustment if I want to use Ilford's formula, etc.

[Drew Wiley]

If it is OK to give a bit of advice, I'd say keep it simple and stick with one particular film in this respect. Among Ilford films, the most predictable straight line is FP4. The only "silver bullet" out there is Fuji ACROSS. I still keep a reserve box of that in 4X5 in the freezer for some special project, and it can still be readily acquired for roll film backs. It also exposes and develops very similarly to FP4, though different in its pan response. Second to ACROS for long exp would be both TMax films from Kodak. But since this is an Ilford thread, you have my two cents worth with FP4.

[Pere Casals]

In fact, the rigth way to deal with LIRF (if one needs it) is calibration. In the same way we calibrate a film by plotting a family of sesitometric curves from N-3 to N+3 unsing a 1s (typical) exposure we can also plot a graph for each useful exposure, say for 15s, 30s, 60s, 2', 5' exposures,

With those graphs in the hand (or in the smartphone...) all mistery disapears, we just will guess a resulting density for every important scene spot, so we can decide what exposure and what development having positive knowledge.

The other way was using Acros, and near no LIRF correction. Sadly Fuji burned that extraordinary product time ago.

I would be happy if Ilford would make a low LIRF film.

[Pere Casals]

The only "silver bullet" out there is Fuji ACROSS.

Not exactly a silver bullet, but we still have a choice: hypering.

I was considering accumulating some acros, but I decided to experiment with hypering, more fun.

Here there is an interesting text: http://adsbit.harvard.edu//full/1988...00254.000.html

[David Karp]

Drew, I do use FP4+ and HP5+ even more. I never used FP4+ for low light situations, but I am going to do so now, having learned that it has the better low light characteristics based on the Ilford-derived factor and having seen your comment. I never cared for the TMax films. I tried to like them, but prefer all of the Ilford films over them, including Delta 100 and 400.

Mostly, my low light photos have been successful using my old chart, but sometimes they were not and it was hard to determine why. Next time I am in that situation I will make some exposures with the new calculator and the old chart and see how things come out.

[Drew Wiley]

Excuse my personal preferences, but a Smartphone or calculator is just one more battery-dependent item I don't want in a pack, esp on a long trek where pack space is at a premium and there's no cell reception anyway, in case of emergency. That kind of thing is best done in a trial run and then either jotted down or memorized per representative times. Working with large format in a snowstorm or downpour already has enough steps and gadgets to keep track of without adding yet another.

[interneg]

Reading this thread makes you wonder how on earth generations of photographers made extraordinary night images without voluminous pages of theorising, correction tables and the arcane practices of specialist astronomical photographers...

Apologies for the sarcasm above, but there are some people who could do with a lot less huffing and puffing about zones and reciprocity and the essentiality of one particular (discontinued) film & instead just get on with making images...