How does pre flashing film work with 2-bath pyro and slimt?

[Steven Ruttenberg]

For bw and color neg film? Does preflash only work well with slide film?

How about long exposues in daytime, like 30 min plus or in night time photography for bw and color reversal film?

[Jim Noel]

Pre-flashing was often used with B&W film during the heyday of 4x5 Graphics being used in News photography to give an apparent speed increase to the film.
Some of us use it today in situations where deep shadows need to be brought up in order to print with some detail.

[Mark Sampson]

The why and how of pre-flashing b/w film is well explained in the Ansel Adams tech manuals. If you're combining the three techniques mentioned in the post's title, you're going way off the map; it may be that no one has gone there before you. Expect to do some rigorous testing to find out what works.

[Drew Wiley]

Hard to think of a better way to muddy up the shadow values. If you just have to try it out of desperation, don't overdo it. Due to their limited contrast range, transparency films are the easiest kind to muck up with flashing. One instance where I do sometimes use flashing is for split color temperature in the same scene when using Ektar color neg film, namely, when the higher values are in warm sunlight, but the shadows are in deep blue shade. My flashing attachment is sandwiched into a gel filter holder that mounts onto the front of the lens, and contain both a diffuser sheet, ND filter, and warming filters, so that when I expose a big gray disc (18% neutral gray), it exactly corresponds to a Zone III pre-flash. Then the flashing device is obviously removed for taking the final exposure of the subject itself. Easy to do with leaf shutter lenses. Anything less than ZIII has little effect, and anything more and the correction seems to get above the shadows into the midtones and discolor them. This kind of scenario is very difficult to post-correct in Ektar, if not impossible, so I have a provision for it. But if I can get away with just a simple warming filter like an 81A instead of flashing, that's what I'll do. And please don't give me a lecture, anyone, how you can do ANYTHING in PS. You can't. I've already seen enough of those bellyflops with Ektar to know better.

[Steven Ruttenberg]

Hard to think of a better way to muddy up the shadow values. If you just have to try it out of desperation, don't overdo it. Due to their limited contrast range, transparency films are the easiest kind to muck up with flashing. One instance where I do sometimes use flashing is for split color temperature in the same scene when using Ektar color neg film, namely, when the higher values are in warm sunlight, but the shadows are in deep blue shade. My flashing attachment is sandwiched into a gel filter holder that mounts onto the front of the lens, and contain both a diffuser sheet, ND filter, and warming filters, so that when I expose a big gray disc (18% neutral gray), it exactly corresponds to a Zone III pre-flash. Then the flashing device is obviously removed for taking the final exposure of the subject itself. Easy to do with leaf shutter lenses. Anything less than ZIII has little effect, and anything more and the correction seems to get above the shadows into the midtones and discolor them. This kind of scenario is very difficult to post-correct in Ektar, if not impossible, so I have a provision for it. But if I can get away with just a simple warming filter like an 81A instead of flashing, that's what I'll do. And please don't give me a lecture, anyone, how you can do ANYTHING in PS. You can't. I've already seen enough of those bellyflops with Ektar to know better.

Photoshop is not a panacea. If you have a crap file no way to fix. Ie, you can polish a turd, but it's still a turd.

I do want to try pre-flashing and combining with other techniques. It may not work, but from the descriptions of each and how they work, it seems a plausible approach. Worst, is that it doesn't.

[Drew Wiley]

I recommend testing flashing on roll film first, provided you have a shutter capable of double exposures. That way you can quickly bracket the frames and develop them simultaneously to ascertain the best exposure effect. Keep notes. With b&w the risk is muddying crisp shadow separation. That's why I'd far rather select a film with a long straight line capable of resolving deep shadows to begin with, rather than compromise results flashing. And the habit of people quoting AA repeatedly in this respect ignores the fact that most of the specific films he used are long gone, he seldom used pyro, and not all his prints are in fact up to par with what can be much more easily done today using VC papers. As far as his advice with flashing color films goes ... he was largely guessing. It is easier to learn with slide film simply because you can slap the film on the light box and see what you got. But with positive chromes, you generally have to flash as high as Z IV to achieve anything noticeable, and by then it's too noticeable. Avoid Velvia. Color neg films are more cooperative with flashing, and you can do it for Z III where the net effect is less blatant. I'd also aim for Z III with b&w films like FP4, at least as a starting point. I mention FP4 simply because it's a middle of the road film with a good straight line section, but not as long as TMax, which does a better job resolving shadows on its own. Have fun. I suspect it's just a rite of passage, once taken by many of us. But something useful is always learned.

[Steven Ruttenberg]

Thanks for the input. I suspect, it is just my inner scientist wanting out. Plus, I will learn even more of the film response/s to different techniques, etc. It sure beats just exposing a bunch of film and then deciding which one/s look better to you. I will be able to see the effect of doing nothing, n+1 or 2 only, slimt only, 2-bath only and combinations of each, even using different developers for the N+1 or +2 only development and in combination with the slimt.

I will need to write the "experiement" and what the goal is, then figure out how many sheets I will need to image the scene enough times to do the different tests. At least half the frames with pre-flash and half without, but all exposed to render the deepest shadows.