Graphics Programs Reference
In-Depth Information
studio lighting environment and carefully photograph the targets
whereas others suggest that the target must be included in each scene to
properly profile how the camera records color. Let's take the side of the
experts who suggest that carefully photographing a camera target in the
studio is the key to producing a single camera profile first.
In the studio, the best way to light the target is as evenly as possible
to ensure no glare is seen on any of the patches. Placing some white tape
to each edge of the target can make it easier to read the numeric values
to ensure all four corners are lit as evenly as possible using Photoshop's
info palette. It is a good idea to place a large black sheet or cloth in front
of the camera with a hole cut in the center large enough that the target
can be seen by the camera. This black sheet of paper, cloth, or foam core
will reduce stray light in other areas of the studio from hitting the target.
Using black material behind and around the target is also recommended
for the same reason. You want to ensure that no stray light bouncing off
a colored object can fall onto the target. In such a situation, you can pho-
tograph the target with one or two lights so that each corner of the target
produces numeric values that are within a point or so as read by
Photoshop's (or a host software) info palette.
Some suggest that a single light be set as close to the lens axis as pos-
sible whereas others suggest two lights at a 45-degree angle or what many
photographers call “
copy lighting
.” The advantage to one light is that only
one illuminant and color temperature is hitting the target; however, pro-
ducing a high degree of even light is more difficult than using two lights.
The downside of two lights is that even with electronic flash, finding two
units that produce identical color temperatures is difficult. Some users
have found that even a few degrees of color temperature difference in
the lighting can cause issues with the resulting profile. To digress, I should
point out that those users who wish to read the color temperature of
either electronic flash or continuous lighting can do so with the Gretag-
Macbeth Eye-One Pro Spectrophotometer and the accompanying Eye-
One Share software. This can be a useful tool to see if the two lights for
shooting the color target is within close specification. If the final studio
situation is such that the photographer is photographing artwork and
using polarizing filters over the lens or lights, it is important that the
camera target photographed this way be measured with a Spectropho-
tometer also using a polarizing filter, as this will affect the accuracy of
the TDF. A Spectrophotometer, such as the GretagMacbeth
Spectrolino
allows a polarizing filter to measure a camera target.
If the host software that is driving the camera allows a gray balance
to be applied, now is the time to do so. Try not to white balance using
the whitest patch since this could affect the tone and overexpose the
image. Exposure is critical and like setting up the scanner for optimal data
capture, it's very important that the camera target be photographed with
as much care. If you can view the data prior to shooting and get numeric
values from the target, try to keep the white patch from going over an L
