Hello folks,
This summer I'm doing some digital art reproduction of oversized materials (i.e. those that won't fit on a 12x17 flatbed scanner) for a local library. I'll be renting a tethered Hasselblad H4D-40 with two Profoto lights for about a month (approximately $3,000 to rent insured). In the past I've used a Nikon D3x with the Profoto lights but found it didn't give enough resolution without having to stitch pieces together which drained valuable time. The Hasselblad seems like the best balance between price and image quality for the client's needs.
Archival in this instance is defined as 6,000 (non-interpolated) pixels on the long dimension while keeping the image as close to the original as possible.
A scanning back system is out of the question because no one that I'm aware of rents out the back or the necessary HID lights, and if anyone did, I imagine the cost would be much more considerable than the Hassy. Not to mention, one has to rent a 4x5 studio camera, lenses meant for digital, etc.
Reproduction with a large format camera with color transparency film is completely out of the question because yet another generation is being introduced into the reproduction process, and film scanning costs would add up very quickly for several thousand images. It MUST be digital for reasons of economy and convenience.
With those disclaimers out of the way, on to the questions:
1. For prints that feature lots of silvering, is there a physical technique I could use to get rid of that bluish, glossed over appearance in the black areas? I've tried cross polarization and lowering the angle of the lights in the past with limited success. If not, what could I do in Photoshop to get back the blacks while maintaining the integrity of the file? While silvering IS part of the print's appearance and age, I feel in this instance the image quality of the reproduction is paramount over archival authenticity.
2. As far as color management, would an X-Rite ColorChecker chart with X-Rite's Passport software work well enough? It uses the chart to create a DNG RAW color profile that can be applied to all subsequent RAW images. Or do I need software that actually creates an ICC profile for the camera using the Profoto lights?
3. Is there a precise way of ensuring that the back of the camera is absolutely parallel to the document being photographed? I know the Betterlight scanning back uses an optional mirror/laser system, but I don't know if that would work with the Hasselblad. In the past I've set up a line chart and used rulers in Photoshop to see if the square in the test image was a true square, but it's tedious and still somewhat inaccurate. I've found putting a bubble level on the camera helps, but isn't completely accurate. I'm using a heavy duty copy stand, so I'm more worried about horizontal convergence than vertical, although both will need correcting. Perspective editing in Photoshop is not an option I want to consider unless absolutely necessary.
4. In the past I've incident metered in a nine-point grid (top - left middle right, center - left middle right, and bottom - left middle right), and allowed for no more than a deviation of .1 stop from spot to spot. Do you believe that is sufficient for getting an even exposure?
Thanks a lot for your help!
- Edward
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