Expose at box speed? - Portra 400, and Candido 800?

[Jon Warwick]

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Hi, after spending all my film days either with E6 or B&W, I’m now dipping into C41 with Portra 400 (clearly very well known) and something called Candido 800 (in the shop, at least, they reckoned it was a tungsten movie film with the remjet layer removed).

Would you expose them at box speed, or something else?

I’d assume more of you have views on Portra 400, but if anyone knows anything about Candido 800, I’d be delighted to hear!

[Mr.Prime]

I've not used very much Portra 400 but tend to follow the trend with negative films towards over rather than under exposure. I usually set my lightmeter below box speed (Portra at EI200). There's a 'signature look' to Portra that requires some intentional over-exposure to achieve more pastel like colours.

Edited December 21, 2023 by Mr.Prime

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[Anbaric]

Portra has lots of latitude to overexposure but less to underexposure, so it's quite common to rate it at a lower ISO, as above:

https://petapixel.com/2018/02/05/test-reveals-exposure-limits-kodak-portra-400-film/

Candido 800 may well be Kodak Vision3 500T without Remjet like CineStill 800T, which is often shot at 500.

Edited December 21, 2023 by Anbaric

[Jon Warwick]

4 hours ago, Mr.Prime said:

I've not used very much Portra 400 but tend to follow the trend with negative films towards over rather than under exposure. I usually set my lightmeter below box speed (Portra at EI200). There's a 'signature look' to Portra that requires some intentional over-exposure to achieve more pastel like colours.

Many thanks, very helpful. Your tendency towards overexposure seems to tie in with Anbaric’s useful comments (and link) too. And as per Annaric’s comment re Candido, I will start off exposing slightly more “open” too for that film as well. Thanks both! I will endeavour to come back with my findings over the coming weeks once I’ve shot some images. 

Edited December 21, 2023 by Jon Warwick

[Mute-on]

Having shot Portra 400 at both box speed (400) and overexposed by one stop (200), I still prefer box speed. Using my metering approach with an incident meter and an M2, or internal meter in MP, I seem to get slightly denser colours at 200. 

I would try Portra 400 at box speed for a couple of rolls first before systematically overexposing for your preferred look. 

Edited December 22, 2023 by Mute-on

[sometimesmaybe]

On 12/22/2023 at 4:14 PM, Mute-on said:

I would try Portra 400 at box speed for a couple of rolls first before systematically overexposing for your preferred look. 

thats a sensible approach.

i find for my use case - overexposing by 1 stop (for all colour neg film) gives me a greater safety margin

[hansvons]

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On 12/21/2023 at 7:31 PM, Jon Warwick said:

but if anyone knows anything about Candido 800, I’d be delighted to hear!

On 12/21/2023 at 11:20 PM, Anbaric said:

Candido 800 may well be Kodak Vision3 500T without Remjet like CineStill 800T, which is often shot at 500.

Quite likely. However, 5219 Vision3 500T looks best at IE 320, especially when shooting in dim light. At least, that's what cinematographers mostly rate it. Be aware that this film is tungsten-balanced. You will have proper white at 3200K instead of "regular" negative film that is white-balanced at 5600K (sunlight). For best colour in daylight, a Tiffen 85 is recommended (an orange-tinted filter that converts 5600K to 3200K). Without that filter, your images will appear bluish. You can correct that to a certain extent in post, but that will have (interesting) consequences for skin tones and other colours (greens will have a slight cyan look, and skin can have a more porcelain touch in soft light).

If you develop yourself, shooting cine colour film has many advantages: it's much cheaper, and when it's Vison3 stock, it's based on Kodak's latest technology, which I think is the Portra line not (I may be wrong, though). You only have to remove the Rem Jet layer, which is easy to achieve as it is basically substituting the pre-soaking step at 39 C* with letting it sit and followed by heavy shaking, plus 8 grams of bicarb and one gram of soda (chemical) per one litre of water.

I don't know why Candido, Cinestill and others market that film as IOS 800. Exposed on the fatter side, it's a gem of a film, albeit prone to slightly exaggerated grain in the shadows. But Kodak's 250D 5207 is even more impressive, and you can expose it safely at IE200/250. Both look terrific when developed in C41, giving them a third of a stop or more speed (my unscientific impression) compared to ENC-2 and a steeper gamma, which is good/not bad for scanning. 

Please note that the Rem Jet layer is there for a reason. When it's removed (Cinestill et al.) before you shoot, you will expose your negative without an anti-halation layer. Highlights will appear reddish. In my eyes, that's a show-stopper.

Edited December 24, 2023 by hansvons

[Jon Warwick]

Hi hansvons, many thanks for your detailed post, it was very helpful and gave me a clearer insight about the various film stocks.

[Stuart Richardson]

I always used to use box speed, and a friend of mine convinced me to overexpose and I did find that I prefer it. If nothing else, if gives you a bit more leeway for scanning. Scanning color negative is not a fun task, and I found that if the neg has a bit more density, it is easier to scan and less likely to show processing irregularities. I generally I rate Portra 160 at 100, and Portra 400 at 200-320. Still, I have made the decision to just stick with slides at this point. Film is so expensive and now slides and portra cost the same, so there is really no advantage to color negative other than in times when I need a huge latitude. I find the colors and character in E6 just so much nicer...

[lincoln_m]

I totally agree with Stuart’s comments. I’ve been a slide film shooter for the past 20 years and as I have 4 Leica film cameras and one digital I thought I’d go back and try film again. Fujifilm Provia doesn’t seem available so I thought I’d try Kodak Portra 400 and like a fool try it out at box speed for the first time on a weekend break to Amsterdam with my old M2 and guess the exposure because everyone says how much latitude colour negative has compared to slide film.

It was a complete disaster! Most of my shots seem to be 3-4 stops underexposed. Scanning the film and adjusting the colours has been the most difficult exercise I’ve ever done. Looking at the curves on the data sheet and helpful YouTube video from Kyle Macdonald I can see that overexposing by 2 stops ( iso100) is the safest way to go. The “toe?” Of the density curves at -3 log exposure (lux-seconds) flatten out and show a big offset for RGB.

The film has a red-brown cast and noisy grain when underexposed. The red bias seems to be for better skin tones (Portra,portraits obviously). The enormous difference in R,G,B density at any exposure makes it very tricky for home scanning even with using auto-levels and using portra400NC in Vuescan. I tried white balance instead of auto-levels in the color tab in Vuescan but that was even more unusable in Lightroom and so I deleted and went back to auto-levels and a brightness setting of 0.6 ( to combat the 2.2gamma used for Adobe RGB output colour space).

For slide film a brightness of 0.7 means I don’t have to apply any S curve adjustment on my MAC (usually 1.8 gamma). But for these underexposed Portra400 scans the slightest change in exposure between shots required extensive manual adjustments in Lightroom so the trick of copy paste of the process settings from one shot to another similar one just didn’t work. Maybe if I use my MP and set the iso100 instead then the exposure and scanning might be easier?

Having learnt the hard way I’ve now looked at the Kodak Ektar100 data sheet and I think that should be exposed at ISO50 (+1stop overexposed) so as to keep away from those flat toe (shadows) part of the curves. If that doesn’t work out then I’ll go back to slide film even if one film +processing costs (£1 per shot) the same as a 128GB Sandisk Extreme Pro SD card, or just give up and get another Leica digital and be done with expensive inconsistent film. 
 

Portra400 does seem to be very high resolution super sharp but the detail is at the same level as the grain. Kodak say it’s the finest grain 400 iso colour negative film, but it might be the only ISO 400 colour neg film on the market so it’s also the most grainy too! I never had these problems with TMAX 100 or 400 black and white. TMAX 3200 I used once was tricky , I’d have to check the data sheet as that might really be an 800 iso film pretending to be 3200 in the way portra400 is really an iso 100 film, in my opinion (experience).

Lincoln
 

[sometimesmaybe]

On 3/15/2024 at 12:00 PM, lincoln_m said:

Portra400 does seem to be very high resolution super sharp but the detail is at the same level as the grain

im going to express an unpopular opinion (for the internet), but i'm not in love with portra 400. i like portra 160 for the detail, but i dont gel with 400. portra 400 might look good in 120, but in 135, i dont see the value over colorplus 200 or gold 200

 

[lincoln_m]

I’m coming to the same conclusion after a week of trying to make good scans of Portra400. I found that in Vuescan using the Generic Colour Negative setting was better than using Portra400NC setting. I also made the mistake of having a UV filter with no lens hood so the M2 was slimmer under my jacket but that just led to shots with flare that I don’t normally have. Even the correctly exposed shots have noisy shadows. Portra 35mm 135 is really putting me off shooting film compared to the positive experience I used to have with Provia100F. 

Film is proving to be an expensive hassle in both time (scanning and post) and money. All the YouTube tests seem to be with 120 film but then they show only small enlargement. Zooming in at 200% in Lightroom (that I do with my M10 shots also) just shows how terrible and inconsistent the results are with horrible colour cast changes between shots taken at most 1 stop difference of the same subject a few seconds apart. I never had that with Provia , may be a slight magenta cast sometimes. But Portra has the ability to give a red, green and blue cast to different parts of the same pavement in the same shot under the same lighting. With slide film the RGB density curves are for the most part on top of each other but with these colours negs they are very separated which I think causes the colour casts if the black and white points for each RGB curve/level aren’t set correctly even after using Auto Levels in Vuescan during scanning. 
Vuescan works fine with Kodak TMax or Fuji Provia but Kodak Portra400 is a real nightmare and I don’t see the dynamic range the 120 film YouTubers seem to report. Even the airport X-ray scanner (twice) shouldn’t have had any effect on iso 400 film.

portra400 has been very disappointing.

Lincoln

[Anbaric]

On 3/15/2024 at 1:00 AM, lincoln_m said:

Fujifilm Provia doesn’t seem available so I thought I’d try Kodak Portra 400 and like a fool try it out at box speed for the first time on a weekend break to Amsterdam with my old M2 and guess the exposure because everyone says how much latitude colour negative has compared to slide film.

52 minutes ago, lincoln_m said:

Even the airport X-ray scanner (twice) shouldn’t have had any effect on iso 400 film.

The old rules of thumb about sensitivity and carry-on scanners don't necessarily apply these days. They have CT scanners at Schiphol that can really mess with your film. If it went through one of those then all bets are off, especially if the guessed exposures were a bit under to start with.

[adan]

1) Bottom line - the hint to Portra performance lies in the name.

It is designed for controlled-lighting studio portrait work. Which means delicate contrast and saturation, and a bias for skin tones (different luminances of pinks, oranges, browns - which are the colors of the skin-tinter melanin (that we usually acquire more of when we get a "tan.").

https://en.wikipedia.org/wiki/Melanin

Take a look at Kodak's "Shirley" skin-test/sample cards over the decades, and you'll get an idea of the "target subjects/uses/colors."

https://www.npr.org/2014/11/13/363517842/for-decades-kodak-s-shirley-cards-set-photography-s-skin-tone-standard

It certainly can be used for any type of photography, but the essential bias will still be there.

2) The neg films closest to slide films are less biased, and have punchier saturation and contrast.

Ektar (which was Kodak's own recommended substitute for Kodachrome when that was discontinued), or the "general-purpose" consumer films (Gold-this, MAX-that, Superia-whatever) - or, when it was available, Fuji's Pro 400. They balanced the blues and greens with skin colors more evenly, for any kind of subject matter.

3) The dirty little secret of color-neg film, however, is that unlike any slide film, it was never supposed to be the final image (axcept for certain artisic experiments). It would always have to be "reversed" by lab-printing or scanning.

And part of that reversal post-processing would be the "orange mask dyes" that develop right alongside the image. Which balances out some color-transimission errors in the color dyes, when projected through an enlarger (or mini-lab equivalent).

And the fact that the orange was produced during the color development meant the process could be a little sloppier (as in, done by "a teen-anger in a parking-lot kiosk," back in the day). (see: image linked from wikimedia).

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Any developing error would change the mask slightly, as well as the image colors, to compensate.

Problem is that consumer scanning software doesn't work like photo paper. It can't fully respond to the masks' color-transmission spectral corrections the way paper does. It expects the "consistency" of color slides.

Which were far more carefully controlled, in both the film production and processing, than color neg materials (and cost accordingly more). Because everyone knew the actual slide film had to be the final product, not just an intermediate step.

[Anbaric]

10 hours ago, Anbaric said:

The old rules of thumb about sensitivity and carry-on scanners don't necessarily apply these days. They have CT scanners at Schiphol that can really mess with your film. If it went through one of those then all bets are off, especially if the guessed exposures were a bit under to start with.

A good illustration of the effect here, with Portra 400 that has been through the CT scanners twice at Amsterdam:

https://images.squarespace-cdn.com/content/v1/5acf8fda2714e5901ad908be/e126807b-a3c7-4563-bc4c-191317eb8b61/400ISO-Portra400-CT2small.jpg

35mm would be a little more protected by the metal cannister than the 120 they used here, but even the film in the lead bag was damaged.

This is from one of the more comprehensive tests of the effects of Airport X-rays on film:

https://www.linabessonova.photography/videos#/airport-scanners/

I think to get valid results about the exposure latitude / box speed of any film, you need metered shots and no X-ray (especially CT) exposure.

[TomB_tx]

10 hours ago, adan said:

Problem is that consumer scanning software doesn't work like photo paper. It can't fully respond to the masks' color-transmission spectral corrections the way paper does. It expects the "consistency" of color slides.

The new Harman Phoenix color negative film has no orange mask. I got a couple rolls to try out - it will be interesting to see how it scans. I'll have it developed and scanned by Dwayne's and then scan myself to compare.

[hansvons]

On 3/17/2024 at 1:37 AM, lincoln_m said:

Vuescan works fine with Kodak TMax or Fuji Provia but Kodak Portra400 is a real nightmare and I don’t see the dynamic range the 120 film YouTubers seem to report.

1. It’s unlikely that Kodak produces with their Vision3 line the best negative 35mm film stocks ever (so good actually that 35mm is getting stronger in Hollywood by the day), but screw up on Portra 400 which is based on the same technology.

2. Home scanning is difficult. For best results, it's advisable to take a deep dive and learn how to convert an orange-masked negative into a white and black-balanced, neutral digital positive by hand without software helpers like Vuescan or Negative Lab Pro.

3. YouTube is full of self-taught amateurs with some sense of mission that often doesn't relate to their expertise. 120 and 135 are mostly based on the same emulsions. Think of 135 film as a zoomed-in version of 120. All things equal, acutance and sharpness are the same on grain level. Same can be said about DR. Only the resolution is vastly different at a given print size.

4. Box speed is misleading. It’s best practice to rate the film’s IE accordingly to the subject and the lens you use. Vignetting causes easily the underexposure of the edges by one stop or more. In the scanning/printing process, this won't lead to darker corners but somewhat grainy edges with colour casts.

When stopping down, vignetting often almost disappears and the film’s IE can be rated closer to the box speed. In low light or night exterior and interior shots that require a pretty open aperture, IE is often set to at least one stop lower. Thus, Kodak 500T Vision3 becomes an ISO 200 film.

Another, albeit minor classic is the measuring the light with an external meter. F-stop measures don't factor in the ND effect of the lens’s glass, which can be as high as half of a stop. That's why there are lenses which render brighter than others at a given f-stop. In cinematography, this issue is solved with t-stops which are the respective f-stops minus the glass’ light transmission loss. 

Bottom line: underexposure and worn-out chemicals (labs tend to save money) are the main culprits for colour casts, dynamic range losses, and overly strong grain.  

 

[lincoln_m]

Thanks for all the comments on my Portra 400 inexperience, I think my problems are

1) Xray (CT scanners, LHR and AMS) First film was in the M2 and second film in carry-on at LHR and second film was in M2 and first film was in carry-on at AMS). I think that lifted the noise floor.

2) Underexposure of cityscapes and building shadow areas. Raises noise floor and increases grain.

3) Non-human (city) subject for which Portra is not suited.

4) Scanning as Generic Colour Neg is better than using Kodak Portra 400 setting in Vuescan. Scanner is Minolta Elite 5400 with 16x scan sampling.

5) No Lens hood but UV filter caused more vailing glare on into the light shots than I usual have when using lens hood and no filter. 

I'll attach an example of one of the better exposed shots.

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[lincoln_m]

And a 100% centre zoom-in. The resolution is good. Lens was 35F2ASPH probably at f11 judging by the DOF so the shutter was probably 1/125th.

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[hansvons]

On 3/20/2024 at 1:00 PM, lincoln_m said:

1) Xray (CT scanners, LHR and AMS) First film was in the M2 and second film in carry-on at LHR and second film was in M2 and first film was in carry-on at AMS). I think that lifted the noise floor.

Scanners can somewhat pre-expose the film, resulting in a lower base ISO. When travelling by plane, the cure is to expose at least a stop fatter by lowering the meter's ISO by a stop. This isn't the perfect remedy, but the results will be less grainy and overall better than when exposed as usual.

Perhaps you may want to look at this post, as the topic is related.