Film scanner profiling question
Posted: Sun Apr 16, 2006 1:44 pm
I used the calibration target and followed the site's instruction to build a film scanner profile, and have a question. Why is it important to shoot the calibration target with *out of focus*? This may create a problem when scanning the shot.
When scanning a regular image, I choose a location in the image and direct the scanner to focus on it with either auto or manual focusing. Typically, the chosen location is where the details are most important or have the highest contrast (e.g. eye lashes). The scans focused this way will show grain or noise structures. But if the calibration target is shot out of focus, there is no such location for the scanner to focus on. If the grain or noise structures are not accurately captured in the target scan, the generated profile may not be handling them correctly.
If there is a good reason to shoot the calibration target out of focus, I wonder if I can introduce a focus point on the film to assist the scanner focusing. By that I mean scribing a small sharp cross hair on the film before scanning it.
When scanning a regular image, I choose a location in the image and direct the scanner to focus on it with either auto or manual focusing. Typically, the chosen location is where the details are most important or have the highest contrast (e.g. eye lashes). The scans focused this way will show grain or noise structures. But if the calibration target is shot out of focus, there is no such location for the scanner to focus on. If the grain or noise structures are not accurately captured in the target scan, the generated profile may not be handling them correctly.
If there is a good reason to shoot the calibration target out of focus, I wonder if I can introduce a focus point on the film to assist the scanner focusing. By that I mean scribing a small sharp cross hair on the film before scanning it.