Re: Betterlight Camera Calibration
Re: Betterlight Camera Calibration
- Subject: Re: Betterlight Camera Calibration
- From: Robin Myers <email@hidden>
- Date: Wed, 1 Oct 2008 11:14:37 -0700
Dear Mr. Smith,
On Oct 1, 2008, at 10:19 , Stanley Smith wrote:
Interesting. However, I have a couple of comments that may temper
enthusiasm for this product. First, conservators at the Getty would
never allow direct measurement of a painting with a device that
touches the surface of piece. Unless the spectral measurements
could be taken at a distance (does such a device exist?), then this
system will probably be relegated to the Giclee world, and not to
major art museums.
There are non-contact devices that can be used for this process.
Better Light has access to one, a PR-655 from Photo Research, and is
engaged in getting this instrument connected for a non-contact
solution. It is a more involved process making measurements with one
of these devices, but Better Light is very aware of the problems
making direct contact measurements and wants a solution for those
fragile surfaces such as pastels, charcoals or wet surfaces, and for
artworks which are too precious to risk contact measurement, such as
museum collections. As soon as the PR-655 capture process can be put
into as user-friendly a form as possible, it will be announced and
made available.
Second, it seems that the proprietary nature of this HP workflow
sees the end point as simply a print — only printed on an HP printer
(in fact a connected HP printer is REQUIRED for operation-- as
Edmund observes-- the biggest dongle on earth). We never store
archival master files tagged with a camera profile-- they are too
subject to changes -- camera firmware and general improvement in
capture technology. I need to be able to open a master file in 10
years (even 100 years), and know what I am looking at. Chances are
that HP printer that was used in this workflow would long be
obsolete, so where does that leave you?
The result of the spectral processing is an ICC profile attached to
the original raw file. This is not a device-link profile, it has no
knowledge of the eventual output device, but it assumes an HP Z3200.
When printed to an HP Z3200, the resulting print is a good match to
the original. However, there is nothing that prevents this same output
file from being printed on any other printer, or simply archived. The
Z3200 serves as the dongle, as Mr. Ronald noted. Prints from a Z3200
may be much better than prints from another printer due to the
increased chroma of the new HP inks. More testing is required to
affirm this HP claim.
Thirdly, this is not really spectral capture. True, there is a
lots of buzz in the painting conservation world regarding spectral
capture, but it is seen as an analytical tool-- involving cooled
chips, narrow band filters, and as many as 20 separate exposures.
Such a gamut is huge-- well into the IR and UV. All very
interesting stuff (see: Lumiere's capture of the Mona Lisa), but
the value is in the quantitative data and analysis-- not simply the
ability to make a better first print. This system uses
Betterlight's (wonderful) tri-linear array-- this is RGB capture,
not spectral capture.
Correct, this is not spectral capture. It is, however, spectral
calculation of a scene-referred ICC profile, and perhaps the
respondents to this list are not being as precise as they should with
their descriptions.
Lastly, I am very interested in this tool as a way to create a
better camera profile that can then be converted to a big RGB
working space. But if my ability to do this somehow prohibits me
from using the data if I have an Epson in my workflow, then I am
much less interested.
It is a custom ICC profile for a specific artwork. After the profile
is generated there is nothing preventing further transformations of
the profile.
Regards,
Robin Myers
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