Orange mark on photos

[rubric]

For some weeks now, the photos that I get from a lab have a bright orange mark at the edge. Is it a problem with my lens or the lab's printing? It's not so clear on b/w photos and some green/dark backgrounds, so I've simulated the mark on the photo below:

I've tried cleaning the lenses and even the camera body.

 

[rumraisin]

I think it's probably the printing-- can't think of any reason why a b&w film would have an orange mark.

 

[rubric]

Not even if there's something orange trapped in the camera somewhere?
The lab's Konota. Anyone with similar experience from the shop recently? Will getting some pictures reprinted at another lab verify that? It's driving me crazy as going for vacation soon.

 

[rumraisin]

No because black and white films are simply incapable of producing colour. Why don't you look closer at the negative and see if the mark is there?