question about long exposure increased contrast

[esearing]

thanks all - Consensus seems to be yes but may or may not need to be compensated for and varies according to light (dim vs bright)
and thanks to Doremus we all now have a way to increase contrast in the field vs development for low contrast scenes. Should be useful for Rocks and Roots scenes.

Guess I will be testing on my next outing to see how FP4+ responds in my usual exposure times vs shorter.

[Steve Sherman]

Reciprocity does most have it's most impact in the mid tones, however, don't think for a minute by applying a ND filter of significance will replicate the gains of an exposure made during the low light levels of dawn or dusk, the light is simply different as the sun arches across in the sky. Photography, especially film photography will always be most impacted by the Quality of Light. There are resaons outdoor TV commericals are filmed in Sweet Light. As mentioned on FB, Sexton devoted an entire book to Quiet Light.

[John Layton]

On the subject of using heavy ND filters in sunlight...I've noticed, on the rare occasions when I actually do this - that I sometimes will get some strange artifacts resembling astigmatism, especially when using wider anger lenses. Using high quality B+W ND's. Never seems to happen in overcast conditions, and less so with longer FL's even in bright conditions. Anybody else ever notice this?

[Steve Sherman]

On the subject of using heavy ND filters in sunlight...I've noticed, on the rare occasions when I actually do this - that I sometimes will get some strange artifacts resembling astigmatism, especially when using wider anger lenses. Using high quality B+W ND's. Never seems to happen in overcast conditions, and less so with longer FL's even in bright conditions. Anybody else ever notice this?

Best educated guess, the severe curvature of the WA lens coupled with yet another glass surface of the ND filter affects some type of artifact or distortion as it exits yet again a dramatic optical formula to cover a large area of film. Years ago I noticed the shots I made with WA lens didn't hold the detail that a longer lens could when the subject matter was nearly the same final size. Particularily since the perfection of the Minimal Agitation technique this anomally IMHO leads me to almost never use a WA lens for my work. My seat of the pants 2 cents !!

[Drew Wiley]

Long exposure contrast is not that simple. You have to test specifically. Different films differ in this respect, and even the same emulsion has different contrast responses to significantly different color filters at long exposures. Even how long "long" means is a factor. So is the film developer.

[John Layton]

Another important aspect that I might add to this discussion is the extent to which subject tonal values can be transient for the duration of a given exposure.

Take crashing surf, for example - where one might interpret the nearly white churn of bubbly water over rocks as highlight values and attempt to place them as such, only to find that those "highlights" are transient...whereas the white, bubbly water present in a waterfall can indeed be accurately placed as it will generally continue to remain in place for the duration of a long exposure.

Another "transient" situation can occur when light changes generally during an exposure - such as fleeting sunlight, or working at dusk in an area where ambient light fades relatively quickly after the sun sets...presenting a moving target of values, requiring continuous recalculation for the duration of an exposure. This happens fairly often in my case when working just after the sun sets in the desert southwest.

At any rate...I typically find the "science" involved in calculating long exposure times to be inexact at best - which I think is a good thing as I am always kept on my toes!