Is this UV degrading the image? Portra 400

[Arthurwg]

Here in my neck of the woods, shooting B&W w/o a filter at 7,000 feet in bright sun, blue skies can go very dark. I thought this must be UV.

 

[DREW WILEY]

7000 ft ? That's the bottom of a canyon where I come from. You'd have to be more specific about which film you are using, and your metering style. Probably not particularly UV related either.

 

[reddesert]

Here in my neck of the woods, shooting B&W w/o a filter at 7,000 feet in bright sun, blue skies can go very dark. I thought this must be UV.

UV light doesn't make images dark (unexposed). At high altitude, especially if it's dry, there is less atmospheric scattering from haze and water vapor, so the sky is bluer (more blue, less white), and even a mild filter like yellow can make the blue sky go pretty dark. Polarizers can also make the sky dark because the Rayleigh-scattered skylight is highly polarized.

If you really have no filter at all, normal pan film, and the sky is going dark, then you're managing to expose in a situation such that the sky is darker than whatever part of the scene you are metering.

 

[pentaxuser]

Why is it definitely a problem? That's the temperature recommended by the manufacturer. I don't think there's any issues with the developing itself as other images are very clean. If there was a problem with developing it wouldn't affect random frames in such a way..

It is a problem because the consensus say that C41 film needs to be developed at 37.8 degrees C or 100 degrees F if you live in the U.S. and any deviation from this temperature risks the dreaded colour crossover. If this occurs and sometimes when it occurs depends on whether you ask what is wrong with a picture and reveal that it wasn't 37.8 degrees C and respondents seize on this as the basis of all your problems

It is clear to me who does not scan that from the miracle of scans such problems are nearly always capable of a scanning rescue so no problem if that is your medium .

It may or may not be a bigger issue if you print via the RA4 process and expose the "afflicted by wrong temperature" negs optically. What I have never been able to get to the bottom of is why a lot of negs developed at similar temperatures to yours are OK and others seemingly are not OK nor have I ever seen an explanation by the likes of Digibase or Tetenal of why they believe that it works fine at less that 37.8 degrees C

Presumably if C41 kits were Covid -19 vaccines then someone would demand evidence that demonstrated exactly why and in what circumstances negs are OK at less than 37.8 degrees C and not OK at said temperatures

So what's the safe way to develop C41? Well it probably is to do it at 37.8. That way you know you have obeyed the rules and whatever has gone wrong is unrelated to that part of the process connected to temperature and more importantly, it allows respondents to concentrate on other factors and not simply deliver one liners that tell you that cause is automatically temperature deviation from 37.8

So in your case was the slight and I mean very slight to my eye, magenta cast the result of 30 degrees and was it impossible to correct this with optical enlarger exposure?

Frankly I don't know without that negative and trying it with an enlarger. Only the taker of the picture of the portrait and only he/she with the ladies skin, hat and anorak in front of them can be sure what the exact colours were.

For what is it worth, I thought the slight magenta cast in your original scan could be corrected with optical filtration as has been demonstrated and that a lot of people with no experience of colour photos might have made no mention of the cast anyway and yes there did seem to be marks on the edge of the shot of the snow laden trees but again it looked an OK shot to me in terms of the picture

I may of course be easily pleased

pentaxuser

 

[mnemosyne]

Show us the negative of the picture with the trees please. I would like to rule out that gross exposure error plays a part in the problem.

Both pictures presented show signs of sloppy processing (streaking, bubbles), so again, I would scrutinize your processing first.

The deviation from the standard processing temperature of 37.8C/100F WILL shift colors (whether that is your problem here, is a entirely different matter).

The BLIX as used in the Tetenal kit is known for causing trouble in the form of retained silver, which will degrade image quality and can cause problems like strange color shifts and excessive graininess. This can happen with insufficient agitation or exhaustion of the solution or simply by the BLIX becoming inactive/decomposing during storage. This is why I would like to know how many rolls of film were processed in this batch and how old the chemistry is.

Another common source of error in C41 is contamination, especially contamination of the developer with blix or fix or bleach, but also the other way round.

The fact that some images appear normal to your eyes and others affected is no reason to rule out a processing problem. In fact, a lot if not most processing errors are typically not uniform over the whole film area.

 

[zanxion72]

Looks like overexposed to me. Overexposing the Portra 400 by a couple of stops gives that yellowish-green cast.

 

[brbo]

Post a direct scan (scanned as positive) of a strip of film that includes the problematic frame together with others that look fine.

There is no way to judge a negative through an inverted scan that went through unknown digital manipulation (inversion, levels, curves and other adjustments). I mean, if you judge a negative in such a transformed form, you'll soon have people saying it's because of UV radiation...

 

[Arthurwg]

7000 ft ? That's the bottom of a canyon where I come from. You'd have to be more specific about which film you are using, and your metering style. Probably not particularly UV related either.

Are you on oxygen?

 

[DREW WILEY]

Oxygen. Are you kidding? I grew up in the Sierras and until recently owned property adjacent to a canyon where the elevations went from a feet hundred feet to over 14,000, and have always breathed better at high altitude. I had terrible pollen allergies as a child, so spent a lot of time above timberline where the air is much cleaner. I live on the coast now, so of course it takes a few days to get re-acclimated; but I always feel best around 9,000 to 12,000 ft. Above that it's harder to find cover in a storm; and now in my 70's, I don't pack as heavy and wind-resistant a tent as I once did. Unfortunately, the past summer had horrible forest fire smoke everywhere that rose as high as 65,000 ft, so there was no way to get above it. So it was the first year in over 40 years that I didn't get a high altitude backpack trip in. But I have had a few trips spoiled because I had to haul out some Los Angeles type person who tried lugging over a 12,000 foot pass the first day and brought along a roast beef sandwich for their lunch. Bad idea. First few days out, you want easily digestible foods. I've never been at really high altitude myself, but have had friends who went up Everest, K2, and Kanchenjunga - the top three - without supplemental oxygen. That's quite a feat. I have another friend who has been a longtime guide up Mt McKinley (Denali), who never brings oxygen, but had trouble around 23,000 ft in the Himalayas when on a climbing trip with my nephew.

 

[vickersdc]

I scan Portra 400 on my Epson V850 Pro scanner and also get a slight shift in colour towards magenta. Personally, I think it's a scanner thing and adjusting for the colour cast when scanning sorts the problem out. It might be worth Googling "magenta colour cast Portra 400 film" and looking through those results for any hints / tips.

 

[YoIaMoNwater]

Show us the negative of the picture with the trees please. I would like to rule out that gross exposure error plays a part in the problem.

Both pictures presented show signs of sloppy processing (streaking, bubbles), so again, I would scrutinize your processing first.

The deviation from the standard processing temperature of 37.8C/100F WILL shift colors (whether that is your problem here, is a entirely different matter).

The BLIX as used in the Tetenal kit is known for causing trouble in the form of retained silver, which will degrade image quality and can cause problems like strange color shifts and excessive graininess. This can happen with insufficient agitation or exhaustion of the solution or simply by the BLIX becoming inactive/decomposing during storage. This is why I would like to know how many rolls of film were processed in this batch and how old the chemistry is.

Another common source of error in C41 is contamination, especially contamination of the developer with blix or fix or bleach, but also the other way round.

The fact that some images appear normal to your eyes and others affected is no reason to rule out a processing problem. In fact, a lot if not most processing errors are typically not uniform over the whole film area.

Post a direct scan (scanned as positive) of a strip of film that includes the problematic frame together with others that look fine.

There is no way to judge a negative through an inverted scan that went through unknown digital manipulation (inversion, levels, curves and other adjustments). I mean, if you judge a negative in such a transformed form, you'll soon have people saying it's because of UV radiation...

Yea I agree. It's hard to pinpoint the problem without a scan/picture of the actual negative itself.

 

[grat]

FWIW, when testing DSLR scanning vs Epson v800, I noticed a definite magenta cast in the shadows that wasn't present on the DSLR version.

 

[laingsoft]

Why is it definitely a problem? That's the temperature recommended by the manufacturer. I don't think there's any issues with the developing itself as other images are very clean. If there was a problem with developing it wouldn't affect random frames in such a way..

The amount of crossover your brain is capable of ignoring is going to be dependent on the content of the image, so the same amount of crossover in the white landscape would be more apparent than crossover in a portrait.

The development and diffusion curves for C-41 are calibrated to 3'15" at 100F, deviation is going to give you shifts, period. As for the The Tetenal instructions I as far as I can see they don't ever mention 30C for anything. I see 3'15" at 100F, 8'00" at 86C and 2'00" at 116F.

 

[Mesabound]

Both pictures presented show signs of sloppy processing (streaking, bubbles), so again, I would scrutinize your processing first.

+1, that first image has a number of issues. Also, like others I live at elevation (6500ft) and have never had UV affect images in such a manner.

 

[YoIaMoNwater]

The amount of crossover your brain is capable of ignoring is going to be dependent on the content of the image, so the same amount of crossover in the white landscape would be more apparent than crossover in a portrait.

The development and diffusion curves for C-41 are calibrated to 3'15" at 100F, deviation is going to give you shifts, period. As for the The Tetenal instructions I as far as I can see they don't ever mention 30C for anything. I see 3'15" at 100F, 8'00" at 86C and 2'00" at 116F.

Tetenal does suggest alternate processing at 30C which I have used initially. Like people have said here, I think that's the issue since I also got magenta casting when processed at 30C but when processed at 38C the magenta shift wasn't there. Honestly, processing at 38C is way faster than at 30C and I haven't looked back since.

Btw do you mean 86F? Because that's the same as 30C.