For all you CSI fans, I've got a mystery...

[tkmusgrave]

Hey all! I'm a university lab assistant, and I've had some mysteries in the past that y'all have helped me solve , like light leaks in the darkroom and what it'll do. I've got a new one tonight. A girl came in with her roll, she developed it and came up with the first 7 or so pictures fine...the rest of the strip was streaked with these black lines:

http://www.facebook.com/photo.php?pid=30402347&l=4b3aa881bf&id=177000712

Any ideas? Obviously something with the camera, but what exactly would it be? She shot off another roll that night and everything went fine, and all of her pictures turned out. What should we look for?

-Tanya

 

[nickrapak]

Check how she rewound the film. Lines like that are almost always formed by accidentally rewinding the film backwards.

 

[tkmusgrave]

Thanks I'll check...but wouldn't those lines be on top of other images? None of her later shots turned out...not even a faint frame can be seen.

 

[ozphoto]

Yep, these are "stress"marks from the film being rewound backwards.
I lost count of the number of rolls we had that showed these marks when I worked in a semi-pro lab. Even more noticeable on neg film, as the marks show up as a lovely shade of green when printed!

Still trying to work out though, how you can rewind a film "backwards"???

 

[Jeff Searust]

After the first 7 the film was not exposed and was wound backwards into the canister. Lines are stress marks on the film from being rewound backwards.

 

[tkmusgrave]

Thanks for the heads up! Though one more question...how exactly does someone rewind the film backwards??

-T

 

[Alex Bishop-Thorpe]

You crank the film rewind in the opposite direction, takes some effort but you can do it by accident...My little sister did it recently with a roll of colour neg, luckily the green lines kinda suit the fireworks in the photos.

Neat trick, maybe there's a creative application for this