Wednesday, February 01, 2012

I am working on a 1969 film created from a television show about the blues. The broadcast was in Black and White and was printed to B&W film from a tape source (I assume). The audio track on the film is a density sound-track.

I noticed that when I was rendering the frames there was an intensity halo floating around the center of the frame. I then removed the “force to grayscale” and realized the intensity halo was actually a rust looking stain that was sort of (and I use this term loosely) centered around the frame. I then boosted the chroma to accentuate the colour to get a better view of the stain.

The stain can be seen with the naked eye.

I am familiar with rust – oxidation on old B&W film the appears as dots strongest around intensity gradients – for example https://pbase.com/filmworks4ever/image/112251501

But this wide areas faint stain unrelated to the image content is a new one – any ideas???

The best way to see this is by selecting one image and then hit “next” “next” to see the colour turned on and then enhanced. Each set of three are from adjacent frames of the film -

John Gledhill