Portra 160 shot at 1/200 - push?

I am shooting this at 1/200 in my Minolta Autocord. I found somewhere that I can push by 1/3 stop during C-41 to account for this. However, is it really necessary? If I don't push will I end up with less contrast? Less saturation? If I do push by 1/3 is there a published/accepted correction amount specifically for 1/3 stop? The FPP website comments only address full stop push correction (i.e., add 1 minute and 40 seconds for one stop and 2 minutes and 25 seconds for 2 stops). This is not linear so I am nervous about interpolating between zero and 1 stop push times. Doing a graph suggests roughly a 30 second increase. Is that a safe approach? Thanks!

ggray79 said:

at 1/200

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You mean you're rating it at 200 instead of 160? You don't mean 1/200 as in one-two-hundredth of a second, do you?

ggray79 said:

However, is it really necessary?

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First demonstrate to yourself that the shutter of your Autocord at all speeds is within 1/3 of a stop accurate, and that your light metering is likewise within 1/3-stop precision. Perhaps then start worrying about your 1/3 stop deviation from the film's ISO rating. Which, I would add, I would deem quite unnecessary; why not meter for 160 in the first place? Not that it matters too much with the "let's just get in the ballpark of sorts" meter your Autocord may or may not be equipped with.

ggray79 said:

I am nervous

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Don't be, enjoy making images
If you need to worry about technique, start with the things that really matter. Your 1/3 stop deviation isn't one.

koraks said:

You mean you're rating it at 200 instead of 160? You don't mean 1/200 as in one-two-hundredth of a second, do you?


First demonstrate to yourself that the shutter of your Autocord at all speeds is within 1/3 of a stop accurate, and that your light metering is likewise within 1/3-stop precision. Perhaps then start worrying about your 1/3 stop deviation from the film's ISO rating. Which, I would add, I would deem quite unnecessary; why not meter for 160 in the first place? Not that it matters too much with the "let's just get in the ballpark of sorts" meter your Autocord may or may not be equipped with.



Don't be, enjoy making images
If you need to worry about technique, start with the things that really matter. Your 1/3 stop deviation isn't one.

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Excuse me, I meant ISO200. The 1/200 came from the Sunny 16 rule when I use the 16 aperture. As to shooting at the 160 box speed my Autocord is new to me and does not have "clicks" for shutter speed and aperture. It doesn't have a meter so there is no ISO setting. I think, but I am not sure, that it would let me position the shutter speed between 1/100 and 1/200 (i.e., very close to 160), for example to use Sunny 16 at the 16 aperture setting. These comments suggest that splitting hairs for the deviation from the 160 box speed is not worth it, so I will probably just use C-41 without a pushing adjustment. Thanks!

I don’t know where you read something like that. Almost nobody would even consider that approach.

Consider ISO200 to be close enough to box speed. Concentrate on good and fun images and enjoy photography. Don’t become a slave to minuscule technicalities.

Don't push Portra unless you really have to. Portra looks best over exposed 1 stop.

BrianShaw said:

I don’t know where you read something like that. Almost nobody would even consider that approach.

Consider ISO200 to be close enough to box speed. Concentrate on good and fun images and enjoy photography. Don’t become a slave to minuscule technicalities.

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The stop adjustment is in The Darkroom chart. Just information - they don't comment on whether it needs to be done.

Very interesting; thanks very much for identifying the source. The Darkroom is a really good lab. I use them and always satisfied. Their site has a lot of great information, too. It’s interesting that they don’t comment anywhere (I just skimmed several of their pages on push/pull processing) when it might be “worth it” or not. I also never noticed how they will do almost any level of push/pull. It’s not a technique I favor so I don’t pay too much attention… only recalled seeing push/pull in 1- and 2-stop increments. I now know more!

Shooting at ISO 200 versus ISO 160 is well within the exposure latitude of the film. Shoot it a ISO 200 and at worst you might have some slight shadow loss.

Color neg film has tremendously wide exposure latitude, resulting in great exposures with zero push/pull processing! You can overexpose color neg to +3EV and underexpose by -2EV with little visible loss of quality. I would not at all alter processing for a mere +-0.33EV !
Shooting color transparency, one can ask a good lab to push/pull for a fraction of f/stop from 'optimal' exposure.

You've underexposed it somewhat, but it will probably turn out OK any unless the scene contrast is exceptionally harsh. These current pro color neg films are intended for box speed exposure - 160 in this case. Advice to overexpose color neg film belongs in a bag with mothballs in it, along with Great Aunt Sue's antique pillbox hat. And don't use alleged "latitude" as an excuse for careless exposure. We all sometimes make mistakes and learn from them. But this particular error isn't all that bad. Best not to try push processing; these later films often don't respond well to that.

wiltw said:

You can overexpose color neg to +3EV and underexpose by -2EV with little visible loss of quality.

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No. Especially not -2EV.

One can water down coffee 300% percent and still drink it. But that's not to my taste. And don't say it's all the same; it isn't. Certain films like Kodacolor Gold were deliberately engineered for amateur use allowing a considerable amount of potential exposure error as well as poor film storage conditions beforehand. But what do
many of those casual snapshots look like? So yeah, you can indeed abuse Portra as well, or perhaps deliberately skew it for some kind of creative result, but there will likely be a real penalty somewhere in the hue balance or dye cloud structure.

Here is Portra 400 deliberately underexposed and overexposed, to see how that reacts to 'not perfect' exposure

Sunny 16 doesn't work like that. The whole system isn't precise enough (and same likely goes for your shutter and probably the aperture adjustment mechanism) to know you're underexposing 1/3 stop. With negative film, it's generally better to err on the side of overexposure, so just use the next longer shutter speed or open the aperture a bit more when in doubt. If however your subject matter is low contrast, the push could be welcome.

wiltw said:

Here is Portra 400 deliberately underexposed and overexposed, to see how that reacts to 'not perfect' exposure

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Yeah that's one of the more convincing Photoshop videos. Too bad it doesn't work that way if you print optically.

Photoshop is of course a blessing. Let that be said!

Too bad that trying to cure it after the fact in PS doesn't work so well either. And anything PS can realistically do was done before by all-darkroom anyway, though not necessarily faster. The whole flaw in that put Humpty Dumpty back together again mentality is the failure to recognize that once you're into the territory of curve crossover, you're dealing with mixed mud. ... really, more like mixed concrete. It's awfully hard to get apart cement, sand, and gravel once it's set up. There is a tremendous penalty to hue purity. Most color neg films including Portra (short for "portrait) are engineered to achieve pleasing skintones across a broad range, yet can also render certain other hue categories reasonably well IF stay within certain specified exposure parameters.

Anyone is free to break those rules for whatever reason they please. But photographers often fails the recognize the greater versatility of these current pro films. In fact, any day of the week I can optically print purer color prints from my own correctly exposed negs than anyone is doing in inkjet and via digital correction or manipulation. As the saying goes (ordinarily applied to business software) : garbage in - garbage out. There is an alternative. Photoshop is a curse when people think they can fix any train wreck with it. They can't. And to the degree they might be able, it's a hundred times easier just to expose the film properly to begin with, and if necessary, apply the correct color balance filtration the film needs.

DREW WILEY said:

Advice to overexpose color neg film belongs in a bag with mothballs

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It's actually pretty solid advice. Box speed is the minimum required to give half-decent shadow contrast. There are very few colour negative films that I wouldn't give an additional stop of light (or two) to, based on the likelihood of losing contrast in the highlights and/or achieving optimal saturation.

Ektar 100 is one. Ultramax is the other.

LolaColor said:

There are very few colour negative films that I wouldn't give an additional stop of light (or two) to, based on the likelihood of losing contrast in the highlights and/or achieving optimal saturation.

Ektar 100 is one.

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Well, there are some that say this makes Ektar's blues shift to cyan. Let's put it this way; among the hundreds of Ektar 100 frames I have, I have no proof of the opposite.

Personally, I think it is being too nitpicky worrying about 1/3 of a stop on colour negative film.
It is well within exposure latitude.
Concentrate on your image composition and less on the 1/3 of a stop.

foc said:

Personally, I think it is being too nitpicky worrying about 1/3 of a stop on colour negative film.
It is well within exposure latitude.
Concentrate on your image composition and less on the 1/3 of a stop.

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+1

DREW WILEY said:

Advice to overexpose color neg film belongs in a bag with mothballs in it, along with Great Aunt Sue's antique pillbox hat

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Portra responds very well to overexposure, underexposure less so. +1 stop really enhances the pastel palet of the film.

Unlike Portra 160, Ektar is a high contrast, highly saturated film which deserves to be just as carefully metered as slide film. You get about half a stop more than a typical chrome film either direction before cyan crossover issues start emerging. This problem can be partially controlled by use of an appropriate skylight or warming filter at the time of exposure. But trying to post-correct it is nearly futile.

I should add that right now I'm making large Fujiflex prints from Ektar sheet film, both 4x5 and 8x10. At that kind of effort and expense, I might as well be throwing hundred dollar bills one after another into a bonfire if I didn't understand this film well. But I learned the hard way, and just wish someone had given me the kind of advice up front which I'm offering others here. Eventually, a pro Hollywood cinematographer did. Of course, they use somewhat different color neg films than most of us do. But by paying attention to things like filtering for correct color temperature response, and tight metering, one can get the most out of any color neg film.

I stumbled across this rather recent post by Mr. Bill, who articulates the testing done in this post on Photrio about the color neg film with best dynamic range and exposure latitude. Its content is very apropos to this discussion! A key statement that succintly summarizes the result:
"Professional color correctors essentially could not tell the prints apart."


Yes, one needs to consider that the dyamic range of the scene is rather carefully controlled to be limited in the context of studio portraiture, whereas inherent scene brightness range is more challenging for film to capture. We know color neg yields more 'muddy' color in the shadows, which is why so many professionals rated their color neg film to lower EI than box speed (effectively to give more exposure than indicated by box speed) to avoid muddy shadows in photos. This was done quite routinely even by wedding pros shooting in the not-controlled lighting of wedding shots outside. The 'harm' done by rating ISO 160 film to EI 100 was not perceived.

Spot on. Typical color neg films optimized for skintones are artificially warmed in the shadows. Glad to see that someone else besides me describes that as mud. To get out of the mud, an amount of overexposure was once commonly recommended, though there can be a penalty to that too if it's excessive. Ektar is different, and trends cold and cyan when it's out of bounds. And in that case, you need to be more careful with exposure placement. But the reward is greater hue accuracy, or better differentiation, of hues which might otherwise get "dumped" into a muddy skintone look themselves in other CN films.

Of course, a lot of well-known own work has been done by taking advantage of the idiosyncrasies of traditional color neg films, especially in the 70s. Take a look at Stephen Shore's book, Uncommon Places. Every photo in there plays off the pumkin-ish trend of yellows and tans versus an outright clash, but a carefully controlled clash, straight across the color wheel to "poison green", a cyan inflected off-green, or sometimes blue instead. Others particularly took advantage of the "mudiness" characteristic of Vericolor L, like Richard Misrach's desert pictures, which created a psychological feel for the desert, but don't replicate the actual hues well at all.