ywenz
Veteran
I gather that the Kodak BW400CN can be pushed up to 1600. My question now is, would most walgreens film department be able to do that? Is it simply requesting the film to be processed as if it's a 1600iso film? thanks
C41 B&W pushing. How?
- Thread starter ywenz
- Start date
- Latest activity Latest activity:
- Replies 19
- Views 2K
kaiyen
local man of mystery
I don't think the local walgreens will push the film - dev it for longer. You will likely need to go to a pro lab for that.
That's a pretty hard push for that film though, isn't it?
allan
That's a pretty hard push for that film though, isn't it?
allan
Graham Line
Well-known
C41 film can be pushed two stops but I'd be surprised if a Walgreen's was willing to alter their standard process. They can't be getting a lot of requests. I'd be more inclined to try something like Neopan 1600 or conventional B&W film first.
ywenz
Veteran
what about just not saying to "push" it, at the risk of getting them confused. Can I just black out the speed label on the cartridge and tell them this is 1600iso film? <- would that be effectively "pushing" it, or does pushing involve something else?
jlw
Rangefinder camera pedant
Pushing C41 films is done by extending the first developer time. In a minilab-type machine, this can be done by waiting for the film to get all the way into the first developer tank, then shutting off the machine for a specified period. (Sounds crude, but some minilab machines specifically documented this procedure in the instruction manual and included info about how long to shut down the machine for a 1-stop or 2-stop push.)
I used to get this done at the minilab run by a local camera store. They'd hold my film until the end of the day so they could push it without messing up anyone else's. I don't have any examples of the results handy, but as I recall they were reasonably decent -- grain got very large, and shadows had a somewhat "smokey" look, but they printed OK. Today, using a scanner, you probably could get pretty good-looking results from this technique.
I used to get this done at the minilab run by a local camera store. They'd hold my film until the end of the day so they could push it without messing up anyone else's. I don't have any examples of the results handy, but as I recall they were reasonably decent -- grain got very large, and shadows had a somewhat "smokey" look, but they printed OK. Today, using a scanner, you probably could get pretty good-looking results from this technique.
kaiyen
local man of mystery
C41 is a fixed process. All films, regardless of ISO, go through the exact same process, including times. So telling them that it's a 1600 film won't do you any good - it'll still be processed as normal. It's just that 1600 film, _real_ 1600 film, is more sensitive to light and got enough exposure, that's all.
As others have said, you need to get them to actually leave it in the first developer longer.
allan
As others have said, you need to get them to actually leave it in the first developer longer.
allan
F
Frank Granovski
Guest
Does Walgreen's develop B&W by machine or by hand?
ClaremontPhoto
Jon Claremont
C41 B&W film goes through the minilab with the C41 color. That's one reason people choose it.
I have had Ilford XP2 pushed a stop in processing, and I'd prefer the subject film to have been exposed in fairly low-contrast conditions, as otherwise the highlights, which are otherwise I bullet-proof, tend to get blocked up when pushed. I normally treat the film as if ISO 250, so setting the meter to 800 is really stretching it for me anyway.
ClaremontPhoto
Jon Claremont
When XP2 first came onto the market about twenty years ago Ilford said that you could rate it at 400, 800 or 1600 ASA. All on the same roll and all without push processing. I never really used it seriously though.
ywenz
Veteran
Jon Claremont said:
You mean shooting a mixed batch of 400, 800, and 1600 pics on the same roll and it would still come out? I guess I do'nt know enough about C41 processing because that doesn't make any sense to me.
nrb
Nuno Borges
Color film latitude should allow for push/pulling 1 or 2 stops, depending on the specific film without any alteration in the developing process, so I remember to have read.
Also I usually expose agfa xrg200 at 400ASA and the results after scanning seem good to me.
Also I usually expose agfa xrg200 at 400ASA and the results after scanning seem good to me.
f/stopblues
photo loner
I think I need to read up on C-41, cause I can't get my brain around this.. How can it be a push or pull without a change in developement? What's the variable? If you just plain ol' underexpose by two stops, would it come out correctly? 😕
kaiyen
local man of mystery
A push/pull requires an actual adjustment in development time. That's the definition.
However, the latitude of c41 film in conjunction with the latitude from printing will yield usable prints when xp2 is exposed from 200 out to 800. Of course, "usable" has different definitions. For me, when I'm doing traditional b&w, I use a different developer for pushing, so that I can keep grain down, maximize shadow detail, and control highlights. Since I wouldn't have this kind of control with xp2, I might not consider the 800 EI results to be acceptable. But others might.
allan
However, the latitude of c41 film in conjunction with the latitude from printing will yield usable prints when xp2 is exposed from 200 out to 800. Of course, "usable" has different definitions. For me, when I'm doing traditional b&w, I use a different developer for pushing, so that I can keep grain down, maximize shadow detail, and control highlights. Since I wouldn't have this kind of control with xp2, I might not consider the 800 EI results to be acceptable. But others might.
allan
ClaremontPhoto
Jon Claremont
Yes, it will come out correctly (more or less) because consumer grade C41 has so much latitude.
Jocko
Off With The Pixies
ywenz said:
That was certainly what they claimed. I remember outraged letters in Amateur Photographer asserting XP1 was the end of true photography as any old twerp could now get correct exposures. The writers apparently misunderstood that regardless of film speed the actual exposure still needed to be right...
ClaremontPhoto
Jon Claremont
The C41 film and the process has to have extreme latitude.
That way little itty bitty EUR25 cameras with one shutter speed and two apertures can still produce results.
Meanwhile, we, can rate the film way way up or down.
That way little itty bitty EUR25 cameras with one shutter speed and two apertures can still produce results.
Meanwhile, we, can rate the film way way up or down.
N
Nikon Bob
Guest
FYI this is what Kodak has to say http://www.kodak.com/global/en/prof...f4036/f4036.jhtml?id=0.1.22.14.23.14.16&lc=en . Rate it at 800, shoot it and just hand it in to the lab with no special instrutions. The films latitude allows for this. I think rating it at 800 may result in more grain for lack of a better word. Yes you can shoot the same roll at different speeds and still get a "usable" image on film. I usually rate it at 200 and it shows little grain that way. I am sure if you check the Ilford site it will say virtually the same as what Kodak says. That is the beauty of C41 films in general, can't let the digital people have all the fun by being able to just change ISO settings in camera.
Bob
Bob
Right, pushing and pulling are + and - adjustments to processing. I have had C41 films including XP push-processed one stop, and sometimes it saves the day but at the expense of higher contrast (as expected) and highlights block up readily. Usually, films for C41 process are very resistant to highlight blocking, very tolerant of overexposure. But the processing seems touchier in that regard.f/stopblues said:
Ilford's chromogenic black & white film now known as XP2 Super started off back around 1980 as XP1 400, and used a variation of the C41 chemistry and processing procedure. It worked ok at the commercial labs but tended to be quite flat, low contrast, and I think they expected folks to use their Ilford XP1 chemistry kits (in various sizes) for best processing results. I still have an unused 84 oz kit in my darkroom... The XP1 kit processing gave better densities than commercial processing. I think it was with XP2 that Ilford changed the film to be 100% compatible with standard lab C41 processing and discontinued the home kits.
Ok, so what's this about shooting it from EI 50 to EI 1600 without processing adjustment... Process C41 color films have 3 senstive layers (4 for some Fuji), each dedicated to a different color. The chromogenic B&W films have three sensitive layers too, but all panchromatic rather than color. And they say these three layers each have different sensitivities to light; three "speeds" if you will, in one film. This is supposed to broaden the usability of the film, and as I recall Ilford was reluctant to assign an offical ISO/ASA rating as the film just didn't react like other B&W films in the ISO testing.
I think this is the basis for the claims of a wide range of usable film speed settings. Might be ideal for a box camera, huh. And gives you lots of leeway for exposure errors and unusual situations. So I don't disagree that XP has a wider range of usable exposure than C41 color films. Yet like all Process C41 films, the chromogenics seem to have less tolerance for underexposure than for overexposure. Note that we're talking standard processing here, no "pushing" or "pulling" by the lab.
Less exposure tends to give a grittier grainier look with less shadow detail. More exposure makes the dye clouds closer together for a smoother creamier look, fine shadow detail and contrast, and bright highlights that may look blocked in a machine print but which do indeed have detail in the neg that may call for some burning-in to see in the print. Machine prints on color paper often look dull, as the film tends toward low contrast in order to record that wide range of light and dark. And if the lab tech isn't careful, the color paper may carry an over-all tint that might or might not be pleasant. Usually you need to use a harder grade of B&W enlarging paper to give some sparkle to the print. Easy to adjust this in the scan too, for digital output.
Give it a try yourself, perhaps a test where you shoot 5 different film speed settings (say, 50, 200, 400, 800, 1600), for each picture on the same roll, hopefully with the shots on this roll covering the whole range of lighting conditions you expect to encounter, and see which level of exposure has best results.... and this might vary according to the circumstances. So you might conclude that setting EI 100 is best for a sunny beach, and EI 800 for the night club, or vice versa. But you'll have a better feel for how the film reacts, and some basis for personal preferences. For my photo circumstances, I set the meter to 250.
Last edited:
jlw
Rangefinder camera pedant
ywenz said:
Yeah, that's what they claimed (possibly to compete with the other then-new chromogenic film, Agfa Vario XL, which was marketed heavily around the multi-speed proposition.) And it did work, kinda.
What let them get away with it was the fact that C41-process films have low inherent contrast (because the image is formed by transparent dyes instead of semi-opaque grains) and this made it comparatively easy to compensate for under- or over-exposures in the printing stage.
The results weren't as good as exposing the film correctly, though.
