Originally Posted by
swmcl
I must reply back since I started it ...
I went ahead with my tests and they worked to some extent. I have not seen a 35mm roll of film for so long my idea of putting a ball in each corner really wasn't that necessary as I had imagined. The edges of each frame were fairly clear as it turns out. But the idea itself wasn't a failure. I got a film curve or two for my troubles.
The other day was a very miserable overcast day. I plopped the Kodak grey card against an outside wall and took an incident meter reading along with a spot reading from the card... They were identical. Furthermore, I tilted the card this way and that and they remained identical!
So.. I bought out the ball.
It measured the same too.
The next day was back to a normal sort of clear and direct light that is usual. The ball readings worked when the light source was basically over my shoulder. When the light source was more across the ball there was some more variation.
Lesson learned.
The quality of the light makes a difference and so too the directionality. I think the grey card is shinier than when I bought it because it has been stored in a sealed heavy plastic envelope for many years. It never was more than 2/3rds of a stop different to the incident meter anyway.
Cheers!
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