Did a fire make the mark?

Mr Molony has a photograph of Titanic leaving Belfast on the 2nd of April, that shows a mark on the side of the ship. He believes the mark was caused by a fire in the bunker of No.6 Boiler Room. Evidently, Mr Molony failed to check the accident report. The bunker fire was in No.5 Boiler Room.
The No.5 Boiler Room bunker is on the aft side of bulkhead E, whereas the mark in on the forward side of bulkhead D, a long way from where the fire occurred. The mark is below the well deck. The mark is on the side of No.3 Hold and is much longer than the bunker fire could potentially have produced. Mr Molony says it is a 30-foot-long black streak but the bunker is only 9 feet wide.

During the video, the photograph is being hand-held and moving, and so a distinct image is not possible. Despite that, on the enlarged part of the photograph portholes are visible, though not clearly. On the original photograph, they would be easy to see. Because each deck's row of portholes forms a distinctive pattern, the portholes ought to have been checked off, one by one, to find the precise location of the mark.

The mark can be seen as located (1) above a row of portholes, (2) passing between a higher row of portholes and (3) reaching an even higher row of portholes. This implies the fire must have burned fiercely inside a cabin on one deck and also inside a cabin on the next higher deck, and possibly up to a cabin on an even higher deck. The fire would have had to burn through one deck and maybe two, but that sounds impossible!

There are no portholes immediately above the coal bunkers of No.5 or No.6 Boiler Rooms.

At time 7:41 of the video, Mr Malony's mark can be seen. Note that there is another mark to its right. Compare the two marks. Their shape, size, slope and height above the sea are identical. Neither Mr Molony or his colleague, Steve Raffield, noticed the second mark. Maybe I am the only person ever to have noticed it.

Note that the end bits of both marks snake their streaky parallel paths up the side of the ship within a parallel band that is darker than the rest of the photograph. Maybe something went wrong in the darkroom when the photographic negative or print was being developed in its chemical emulsion, or a wiper or squeegee was carelessly waggled across it when removing the fixer, creating this blemish. At the bottom of the photograph, and particular in its centre, are dozens of black vertical streaks that are not images of any objects in the scene but are flaws in the photo that were likely caused at the time it was processed. What's more, these clearly visible flaws are immediately below the mark and, in fact, join to it. Can the possibility of the mark being a smudge be ignored?

Steve Raffield said he inititially thought the mark might be a reflection, but it never entered his head, or Mr Molony's, that it might be a fault in the photo.

A few minutes later the black mark has disappeared!