Is this UV degrading the image? Portra 400

[Marcin Kolanowski]

Hey guys,

I've recently came back from a holiday in the alps and developed my negatives at home. After scanning the negs I've realised that some of them have a strong magenta colour cast and a very heave grain. I suspect its UV rays as I didn't have a UV filter attached to the lens. Please see the images below - both images were shot one after another. I had a couple of the bad ones on the roll and they both had a bit of sky included in the frame thus my thinking its the UV rays.

I used Epson V550 scanner and Tetnal C-41 developer..

 

[Marcin Kolanowski]

Also - I was driving there and back so the negs didn't get hit by the airport luggage x-ray

 

[Anon Ymous]

Well, no, the shots weren't in sunny conditions to begin with, so no UV. Look elsewhere.

 

[Marcin Kolanowski]

Well, no, the shots weren't in sunny conditions to begin with, so no UV. Look elsewhere.

Good point

I've also just had a look at all 3 rolls I shot and the images affected are all from different parts of the roll (I was thinking maybe they're all first images from the roll but they're not)

Could this be the scanner? I'm yet to buy an enlarger so can't inspect the negatives - I haven't got a loop either..

 

[Wallendo]

Scanner software could be the issue. Occasionally automatic software makes inappropriate decisions for you. Try re-scanning a problem negative with various settings in your software and see if that fixes the problem.

 

[Anon Ymous]

If you have an "auto everything" approach in scanning and depend on whatever your software thinks is correct, then results can be from perfectly fine to seriously ugly within the same roll. If you have made any processing errors, or used old/overused chemicals, then it's even easier to get ugly results. I've seen spectacularly ugly results from scanner software and suspect that this is the case, if your negatives look normal, without any strange cast, or irregularities.

 

[Sirius Glass]

Well, no, the shots weren't in sunny conditions to begin with, so no UV. Look elsewhere.

Clouds, even overcast, do not filter out UV light. So UV light is still a contender. People get sun burns when they are shirtless on the beach during an overcast day. Anon Ymous' advice is dangerous health wise.

 

[mnemosyne]

In the mountains, UV radiation can be abundant even on foggy or cloudy days. But I agree the problem has nothing to do with UV. If the problems seem to be restricted to the sky area of the pictures, it is because such problems usually are more apparent in bright areas of rather uniform density, although they may be present (but just not as visible) in other areas of a picture.

The images show several signs of irregular development (streaking, bubbles), so processing error would be my first suspicion. It would be interesting to know how exactly the roll was developed. Processing temperature, agitation? How many rolls have been processed in this batch of chemistry?

 

[BrianShaw]

What was the elevation?

 

[Anon Ymous]

Clouds, even overcast, do not filter out UV light. So UV light is still a contender. People get sun burns when they are shirtless on the beach during an overcast day. Anon Ymous' advice is dangerous health wise.

Clouds will greatly reduce UV radiation, the heavier they are, the more they'll block UV. If people get sun burns on the beach on a bright overcast day is irrelevant to the OP's problems. And I never said anything about health hazards.

 

[Sirius Glass]

Clouds will greatly reduce UV radiation, the heavier they are, the more they'll block UV. If people get sun burns on the beach on a bright overcast day is irrelevant to the OP's problems. And I never said anything about health hazards.

You are wrong. UV lights pass through clouds. Period. The health issue was a simple example to show that you are wrong.

 

[Marcin Kolanowski]

In the mountains, UV radiation can be abundant even on foggy or cloudy days. But I agree the problem has nothing to do with UV. If the problems seem to be restricted to the sky area of the pictures, it is because such problems usually are more apparent in bright areas of rather uniform density, although they may be present (but just not as visible) in other areas of a picture.

The images show several signs of irregular development (streaking, bubbles), so processing error would be my first suspicion. It would be interesting to know how exactly the roll was developed. Processing temperature, agitation? How many rolls have been processed in this batch of chemistry?

It was developed in Tetenal C-41 @ 30C. It's strange though as the next image next to it is perfectly fine..

Those images were taken at 1600m above the see level.

 

[BrianShaw]

“As sunlight passes through the atmosphere, all UVC and most UVB is absorbed by ozone, water vapour, oxygen and carbon dioxide. UVA is not filtered as significantly by the atmosphere.”

https://www.who.int/news-room/q-a-detail/radiation-ultraviolet-(uv)

 

[Anon Ymous]

It was developed in Tetenal C-41 @ 30C. It's strange though as the next image next to it is perfectly fine..

Those images were taken at 1600m above the see level.

30°C is definitely a problem. You will obviously get a colour image, but crossover is guaranteed. Your scanner software tries to keep up, but it can have a hard time with good negatives, never mind problematic ones.

Regarding UV, I've shot film at high altitude, above 1km and never really had any significant problems. I definitely never had random problems that manifest themselves in one frame and not in the next one that the OP said.

 

[MattKing]

"All I see is a colour cast, most likely attributable to the scanning software, and relatively easily dealt with in "post"

 

[reddesert]

Water and water vapor have a peak transmission around 400 nm, in the blue, not the UV, see eg https://en.wikipedia.org/wiki/Electromagnetic_absorption_by_water . Clouds absolutely do absorb UV, although they absorb UV only moderately more than they absorb optical. The reason people get sunburned on cloudy days is because it doesn't feel hot and they stay out longer, not some transparency to UV.

Many people have taken photos at high elevation (well over 1600 m) on clear days without oddities, I don't think it's the elevation. It can be difficult to meter and expose scenes with a lot of snow correctly. I would lean towards a combination of exposure (varying from frame to frame) and crossover due to the development. The scanner also might be a little unpredictable on snowy scenes.

 

[pentaxuser]

It was developed in Tetenal C-41 @ 30C. It's strange though as the next image next to it is perfectly fine..

Those images were taken at 1600m above the see level.

Maybe the UV when that perfectly fine image was taken was having its coffee break

No-one has asked you if you were wearing any suntan lotion, which factor and how long in those very thick cloud days you were exposed to the U.V. I am assuming of course that these are factors that matter? If not then he only sensible thing is to avoid being anywhere above X metres to be absolutely sure of safety?

It's a difficult choice it seems to me. Either risk the Alps in winter for maybe a fortnight or stay safe in London at almost sea level where the air is full of diesel particulates etc Best bet is the Grampians in Scotland where there is the best of all worlds. Clean air, resorts, clean whisky and well under 500 metres with the sun at about 10 degrees above the horizon at best

pentaxuser

 

[Marcin Kolanowski]

"All I see is a colour cast, most likely attributable to the scanning software, and relatively easily dealt with in "post"

View attachment 263666

This is the example of 'good' image - the image of the trees is the 'bad' one

 

[Marcin Kolanowski]

30°C is definitely a problem. You will obviously get a colour image, but crossover is guaranteed. Your scanner software tries to keep up, but it can have a hard time with good negatives, never mind problematic ones.

Regarding UV, I've shot film at high altitude, above 1km and never really had any significant problems. I definitely never had random problems that manifest themselves in one frame and not in the next one that the OP said.

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..

 

[DREW WILEY]

That's certainly not very high by my routine standards. UV would give a hint of blueness at distance, nothing much otherwise with this particular film. But the blueness in the tree/snow shot is probably just an ordinary color temperature issue, easily controlled with an 81 series warming filter. The magenta is blotchy, not overall, and looks like processing streaks to me, or else banding from the roll not being wound correctly. Don't blame the altitude.

 

[MattKing]

This is the example of 'good' image - the image of the trees is the 'bad' one

On my screen, in your original post, the woman is magenta and the trees are not.

 

[BrianShaw]

That's certainly not very high by my routine standards.

LOL... you’re right. I read 1600 meters but my brain translated to 16000 meters. Big difference...

 

[Anon Ymous]

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..

Because the C41 is meant to be performed at a very specific, higher temperature. You can process at lower temperatures and even get reasonable contrast, but colours will be off, even way off. When scanning, you may get away with it because you have other means at your disposal to correct any processing errors, but it can become very tedious, trust me on this. By the way, the kit instructions basically say about processing at 37,8, but alternatively you can try at 30. It's not the same, but it's an option if 37,8 isn't.

 

[Sirius Glass]

LOL... you’re right. I read 1600 meters but my brain translated to 16000 meters. Big difference...

Merely a factor of ten. Now if it was an f/stop, that would have made a difference. All seriousness aside, look at the film to see if the problem was partially or completely a scanning problem.

 

[DREW WILEY]

16000 meters? No problem. Just stack Annapurna atop Mt Everest and climb up.