Camera Calibration for Scanning

[silvergelatin]

Has anyone used a Calibrite target plus software to generate a camera profile shot on a specific film emulsion? How well did it work out? I just started scanning with an RGB Scanlight and Ektar colors are tricky to balance due to the increased saturation from the light. Would love to make an Ektar-specific profile.

 

[koraks]

Just set the white balance manually on the camera to whatever approximates a decent balance, and then note the settings for both the light source and your camera settings (exposure + white balance). Then use those exact same settings every time.

You could photograph a target like the Calibrite and then balance the colors as well as you can in post; I personally don't think it's worthwhile to use software for this, but you could. If so, you could look into ArgyllCMS, which probably supports the Calibrite targets out of the box. Personally I'd just make a manual curve and use that as a starting point.

Note that you'll run into inconsistencies anyway unless you always shoot with the exact same exposure under the exact same lighting conditions. In reality you're likely working with a variety of conditions as well as normal variations in exposure, so the color balance will always be a little (or a lot) different. The standard curve you could construct as described above can still act as a starting point, but I bet you're going to adjust the balance nonetheless.

All of this assumes your C41 processing is dead-on consistent. If you're serious about the calibration thing, you're upping the ante on the whole imaging chain. I personally don't think this is worthwhile in practice; if you need this kind of consistency then it's more practical to shoot digital.

Keep in mind you're not calibrating 'the camera' - you're calibrating the entire end-to-end imaging workflow. That's a lot of factors to control.