Need advise: Portra400 green color shift while developing at home

koraks · Aug 12, 2024

Skycreeper said:
Here are the 2 rescanned negatives to play with.

Note that there is still severe color crossover on this scan likely due to uneven illumination. There are yellow and blue spots all over the negative. Note how the bottom of the white shirt is yellow while the top tends towards cyan. Likewise, the entire top of the frame is very blue. The floor on which the model stands is bright blue on the left side and and yellow/tan on the right side. The entire bottom left corner is very blue, which is not just due to the lighting/shade. There are still issues to sort in the scanning process.

Big problems on the Portra shot as well; in part these might be due to the overall cyan cast, although the pattern is quite similar to the Fuji shot above, so I think most of this is still due to the light source. Note the massive blue area to the right and how all the shadows go deep blue; this is likely where the cyan cast is presenting problems as it throws the curves out of whack.

Note how in both examples the red, green and blue curves are not parallel. Don't attribute too much value to this, because the digital camera etc. play a big part in this. However, in my experience, a well-scanned color negative (scanned as a color slide, so yielding a direct representation of the actual negative) that is properly processed tends to balance with fairly parallel RGB curves. Many factors can play a role in this, including digital equipment and software, but also film age, process variations etc. Again, don't attribute too much value to this, but the degree to which the curves cross over in this case is fairly extreme.

Here's how I did the inversions: https://tinker.koraks.nl/photography/flipped-doing-color-negative-inversions-manually/

Skycreeper said:
I heard that Portra has thicker emulsion, So demands better bleach and fix.

This is indeed possible and I've noticed a similar difference between Kodak C41 and ECN2 film, with the latter requiring more thorough fixing. I once ran into this issue, which is why I'm thinking you may be dealing with the same: https://tinker.koraks.nl/photography/how-i-broke-my-fixer/ In my case, it was trying to get away with too dilute fixer, which would work the same as an underreplenished fixer.

Skycreeper said:
So I put one strip of already developed Portra into bleach and fix again?

Yes, please, give that a try!

BillBaileyImages · Aug 12, 2024

Fresh chemistry and revised scanning are both required in my understanding. Keep on...Portra is excellent film with the ability to overexpose (some folks say even 5 stops over is possible) and have negligible change in color. Persistence will win out as long as you change only one variable at a time. In medicine it's called the "rule out" approach.

brbo · Aug 12, 2024

What's interesting is that both blue channels (and green as well) are petty much comparable between the two negatives, but red is nowhere on Portra (or in negative speak, is much denser than one would expected). Cyan layer is the lowest so incomplete bleaching and fixing would explain this, but I wonder if it would so obviously be limited to only one channel.

Anyway, as suggested, re-bleaching and fixing in fresh bleach and fixer would be the first stop. Might even cure the problem that we are, maybe wrongly, attributing to uneven illumination...

cerber0s · Aug 12, 2024

Thanks for posting those.

Here's a quick conversion, about one minute per negative with no additional color correction after converting them. It looks to me like the negatives are salvageable, at least after re-scanning. Working from jpg is a little bit limiting.

Look at the film base top and bottom. To me it's pretty evident that there is an issue with uneven lighting in the scanning setup.

koraks · Aug 12, 2024

brbo said:
I wonder if it would so obviously be limited to only one channel.

I've had this happen before, yes. What was different in that case was that there was also unevenness across the film, but overall the effect was also much more subtle in my case. But it was limited to cyan, specifically.

cerber0s said:
Look at the film base top and bottom. To me it's pretty evident that there is an issue with uneven lighting in the scanning setup.

Excellent point that illustrates it well.
I doubt the Portra neg will be really salvageable given the cyan problem on the actual negative. In this particular case it's a combination of factors.

LomoSnap · Aug 13, 2024

Many Portra400s have X-ray and heat fogging problems. Please make sure you buy the imported films from Kodak Alaris dealers. In China, I usually recommend you to buy from "柯达产品经营部".
By the cyan D-min of the film.I think your problem with the film itself.

Another problem is that your fixing time may be too long. The too long fix time maybe can cause leuco dye. This may not be the cause this time, but it is recommended that you correct it next time you process other films.

koraks · Aug 13, 2024

LomoSnap said:
Many Portra400s have X-ray and heat fogging problems. Please make sure you buy the imported films from Kodak Alaris dealers.

Oh, that's a good point; thanks for bringing this up. Now you mention it, there has been this problem with x-rayed Portra on the Chinese market. Maybe that's the cause; it's very well possible!

LomoSnap said:
Another problem is that your fixing time may be too long. The too long fix time maybe can cause leuco dye.

No, that's not the problem and long fixing will not make the dyes in Portra become colorless. Moreover, once they do (e.g. by running the film through a very acidic bath), the dyes regain their regular colors after a wash with plain water.

LomoSnap · Aug 13, 2024

koraks said:
No, that's not the problem and long fixing will not make the dyes in Portra become colorless. Moreover, once they do (e.g. by running the film through a very acidic bath), the dyes regain their regular colors after a wash with plain water.

In <Processing-KODAK-Motion-Picture-Films-Module-8>,Kodak says "Extended fix time (longer than 4 minutes) or high-current density in on-line silver-recovery cells can cause leuco dye in Process ECN-2."
I think Portra400 is a product based on Vision3 technology, may be the same (but I not to test it, Just a guess based on experience).
This is really not a serious problem. can be restored by re-bleach.

LomoSnap · Aug 13, 2024

Corrected to the best of my for the example images.It has a color cast but looks much better.
I used Silverfast HDR for the adjustments, I only used the Levels and Curves tools, no HSL.

koraks · Aug 13, 2024

LomoSnap said:
in Process ECN-2

That's very different in many ways from C41. Most notably the dyes are different since they're coupled with CD3 in ECN2 instead of CD4 as in C41. Coincidentally, if you throw ECN2 Vision3 film into an acidic bath (dilute hydrochloric acid), the dyes go leuco. If you wash the film, the snap back into color mode. It's kind of fun.

LomoSnap said:
I think Portra400 is a product based on Vision3 technology

That's a bit of an unfortunate formulation that found its way onto the web. I understand why some people would put it that way, but it's not the way I'd put it. I recently posted a more nuanced way of formulating it, which boils down to different Kodak films certainly sharing a technology base, but " one film being based on another" is a simplification that is not quite true and moreover has little practical relevance. In this particular instance regarding leuco-dyes I don't think it's an accurate way of seeing it.
PS: I've "overfixed" Vision3 plenty of times. Never saw a leuco dye issue as a result of it.

LomoSnap said:
can be restored by re-bleach.

A simple tap water wash will do.

LomoSnap said:
Corrected to the best of my for the example images.

Not bad at all given the limitations!

Skycreeper · Aug 13, 2024

LomoSnap said:
Corrected to the best of my for the example images.It has a color cast but looks much better.
I used Silverfast HDR for the adjustments, I only used the Levels and Curves tools, no HSL.
View attachment 376156 View attachment 376157

this is excellent! Now I need to get Silverfast

BillBaileyImages · Aug 13, 2024

Great advice from everyone--impressive, and welcome to an old guy (I'm only 79) who may have problems and need help in the future.
One item I've not seen anyone mention is using distilled water when blending your chemistry. Even filtered water, although tempting, is (in my experience) not as clear and contaminant-free as distilled.
Also, mixing can be less-than-complete, so I always use a magnetic stirring plate with a ceramic magnetic slug that is dropped into the solution being mixed. Obsessive? Probably, but in my chem major days, it was the only way we could be sure mixing was complete. Just eliminating one more variable .

koraks · Aug 14, 2024

BillBaileyImages said:
using distilled water

The question is whether this will do all that much, in all honesty. For fix and bleach, it basically doesn't matter one way or another; if the water is safe to drink, it'll mix those chemicals just fine. The developer is a little more picky, but then again, manufacturers know that water supply isn't ideal in the real world, so the developer is compounded with sequestering agents that will bind to the metal ions in the water; particularly iron would be a concern, but that's also specifically addressed. If sequestering is insufficient for the water used (which means the water must be extremely impure), what you'd expect is (1) cloudiness due to formation of insoluble calcium carbonates etc., and (2) potentially reduced lifetime of the developer. The former will have no effect on the images; in fact, I *always* process my ECN2 film in cloudy developer because I don't even bother adding a sequestering agent for my tap-water based ECN2 developer (used one shot). The latter, i.e. reduced lifetime in particular due to iron impurities, will show up as reduced activity of the developer. This means lower overall density. That's not what OP's Portra 400 shows.

Moreover, a chemistry problem would have affected both rolls processed in the same tank.

BillBaileyImages said:
mixing can be less-than-complete

Virtually all commercial color chemistry is sold as liquid concentrates. Mixing will be as complete as it gets if you measure them out in a vessel and then pour them over into a processing tank. With powder / dry chemistry (e.g. Cinestill), this can be a different story, and thorough stirring is indeed required.

BillBaileyImages · Aug 14, 2024

My obsessive preparation of solutions is admittedly "over the top" in terms of real needs and expectations.
I just attempt to eliminate all potential variables and causitive factors.
You are absolutely correct that this recommendation (distilled water) is firmly in the "probably doesn't matter" category. Running large dip and dunk Pako processors (E-6 and C-41) in control with multiple daily control strips and micro-adjustments based on densitometer results is indeed not the same as home processing with one-shot developer technique.
As they say, "Old habits die hard."
And, I am having fun again after years using only digital. Now, Victor and I (Victor is my "new" 501CM) can capture images and not worry about control strips and densitometry to be sure clients' film is processed completely within "specs"--or at least as close as I could get. Now I only process film for me, and the stress reduction is wonderful!
Of course, I do have a transmission densitometer and stirring plate in my home lab

koraks · Aug 14, 2024

Hey, it's better to be a little too cautious than to be a little too lax! I acknowledge your extensive experience also in a pro setting.

loccdor · Aug 14, 2024

I noticed that the images of the OP tend to all have a cast toward the "average" color of the image. In other words, images with lots of plants tend toward a green cast, the one with plants and a red structure tends toward green+red= yellow cast, the sunflower field tends toward yellow cast, etc. Just an observation. Normally when I see that my mind goes to some sort of automatic color balancing algorithm being used. I think that reflected light bouncing around in the digitization process could also potentially cause that.

BillBaileyImages · Aug 14, 2024

We used to call that phenomenon "subject failure," and it especially evident--as you noticed--when similar colors might "overwhelm" a scene and become dominant. In my exexperience, subject failure is more of an issue with the photographer than the film. Kodak even released an emulsion in the late 1970s that would change a groom's suit color from black to brown . The error was corrected immediately by Kodak; but it did cause a brief, but definite, impact for at least a few wedding photographers. Anyone else remember this piece of trivia?

BillBaileyImages · Aug 14, 2024

koraks said:
Hey, it's better to be a little too cautious than to be a little too lax! I acknowledge your extensive experience also in a pro setting.

Thank you! It was a great time in my life, but the 120-hour weeks finally took their toll. Went back to university teaching (programming, systems analysis and design--all the cool computer science topics), and I retired from Park University in 2006. What is your background, or is that sidebar OK on this forum?

koraks · Aug 14, 2024

It's OK, but it's a little off-topic. Partly in the academic world, too, partly in industry, a little government, a little small business. A bit of everything really!

MattKing · Aug 14, 2024

With respect to the water used:
1) we are blessed with very good tap water here - yours may differ;
2) If I'm mixing up something like 5 litres of stock XTol, which may be used for up to 70 rolls of film over 6 months or more, I'll use distilled water; whereas
3) If I'm mixing up a single batch of something that will be used that day over a short period of time with just a few rolls of film or prints, I'll use tap water.
So, as an example, I'll use tap water for print developer mixed up for a single session, but will use distilled water to mix up print developer that will be re-used and replenished.

Mr Bill · Aug 14, 2024

BillBaileyImages said:
We used to call that phenomenon "subject failure," and it especially evident--as you noticed--when similar colors might "overwhelm" a scene and become dominant. In my exexperience, subject failure is more of an issue with the photographer than the film.

Hi, I'm always glad to see ex-lab people on the forum.

I probably have a little more lab experience than you; I would characterize so-called "subject failure" as primarily a printing issue - a result of the automatic color-balance sensor systems once used in commercial printers.

These systems had 3-color sensors somewhere after the negative, so could sorta measure the average color of the light coming through the negative. The idea was that an "average scene" would sorta average out to a neutral color - "integrate to grey" was the term. Long story short such a system would cause the auto-balanced print to go in the opposite direction of the dominant color. Like so: if a scene had mostly green foliage the negative has an excessive amount of magenta dye. As the automatic print exposure begins the sensors say, "whoa! There's way too much magenta here! I'd better cancel this out with extra cyan and yellow filtration!" Skipping the details the print's color gets biased to the opposite of green.

Once full-negative scanners were developed, and they could "see" image details rather than an overall average color, computer could recognize what was going on, and "subject failure" eventually became a minor issue.

BillBaileyImages · Aug 14, 2024

Back on topic then...started my film journey in 1954 with my first Nikon (and I'm still brand loyal). First "Oh my " moment was in 1955 when I thought pushing Tri-X (box speed 400) to 3200 could be accomplished by raising the developer temp from 68°F to 100°F (shades of processing temps to come). Result was clear film and a sediment of silver halide (?) on the bottom of the tank. Guess I exceeded Kodak's design parameters, and since then I've been fascinated with film processing issues and developing solutions to those problems (a double pun hiding there?). Fast forward to processing E-3 at home in Nikor tanks, then 3 1/2 gallon tanks, then E-4, then E-6, and finally had so much processing demand that we moved to a commercial location with 2 Pako dip and dunk machines (C-41 and E-6), a Hope 52 inch Ektaprint 2 paper processor, and roll easels for 8 inch, 11 inch, and 20 inch roll stock (on 275-foot rolls if memory serves). Lots more stories available.

koraks said:
It's OK, but it's a little off-topic. Partly in the academic world, too, partly in industry, a little government, a little small business. A bit of everything really!

Mr Bill · Aug 14, 2024

MattKing said:
With respect to the water used:
1) we are blessed with very good tap water here - yours may differ; ...

A lot of people don't realize that, at least in the US, their local water departments normally have pretty complete water analysis data available for the asking. So if you're on a municipal water supply they can probably tell you just how much iron is there.

A couple of gotchas, though... some places may have dual supply sources depending on the time of year. A second, unexpected thing, could happen if your city uses river water. Another long story short - if the water level is high and tends toward high turbidity, they may have difficulty getting real clear water to their customers. So a fairly common treatment, since about the year 1900 or so, has been to add something like ferrous sulfate ("ferrous" means iron) to the water to help settle out, uh, various crap in the water. But a tiny amount of iron can remain in the water - no issue to humans but can definitely cause issues in a replenished C-41 system, and I'm guessing also for Xtol.

(If anyone has an interest in the turbid river water thing I'm pretty certain a search for "drinking water" and "1904 St Louis World's Fair" will get some results.

Skycreeper · Aug 15, 2024

OK folks, bought new bleach+new fixer+new light box and did the experiment.
#1 Fresh fixer. Put 1 strip of Portra 400 into fresh fixer for 7mins.
#2 Fresh bleach+fresh fixer. Put 1 strip of Portra 400 into fresh bleach 7mins and fixer 7mins.
And the result is.......drum............NOTHING SIGNIFICANT CHANGED, still got cyan cast...sigh...what a disappointment!
Conclusion: Either I give up on Portra400, or I buy from “柯达产品经营部" next time.

#3 Fuji+new lightbox. Result: At least this one does show even lighting now. Please see result

koraks · Aug 15, 2024

Skycreeper said:
Result: At least this one does show even lighting now.

Oh yes, I think that looks a lot better!

Sorry to hear about the Portra; I'm afraid @LomoSnap is right and it was xray fogged.

Need advise: Portra400 green color shift while developing at home

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Need advise: Portra400 green color shift while developing at home

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