Page 123 - Graphic Design and Print Production Fundamentals

Graphic Design 111
For input profile creation, the targets always consist of two parts: a physical sequence of colour patches
and a target description file (TDF) with the profile connection space (PCS) values for the swatches. The
TDF accuracy varies from individually measured targets (done by you or a specialty vendor) at the high
end to averaged samples from a batch run (an economical alternative).

As with output profiling, there are standard scanner target formats. We have IT8.7/1 for transmissive
originals (film transparencies like slides) and the IT8.7/2 for reflective (photo print paper). These targets
are available from a variety of vendors and allow you to match the material of the target to the material
you will be scanning. If you will be scanning Kodachrome slides, you will want a Kodachrome IT8/7.1
target. Conversely, if your originals are Fuji photo prints, then you will want an IT8/7.2 target on the
matching Fuji photo print paper.

The X-Rite ColorChecker targets are commonly used for digital cameras. There is the original
ColorChecker with 24 tiles and the later digital ColorChecker SG with 140 colour tiles. The larger target
can be used for initial set-up and there is a mini version of the original ColorChecker that will work in
most photo shoots for an ongoing reference check.

Though scanners and digital cameras both fall into our domain of input profiling, they have some very
different characteristics that we have to take into account when preparing to produce a useful profile.
As with output profiling, we need to calibrate the device by stabilizing and optimizing its performance
prior to capturing its colour behaviour. In order to stabilize, we need to understand the potential variables
that the device presents. Scanners have a controlled light source and stable filters and typically have
the option for extensive software intervention. In contrast, cameras have stable filters and moderate
software controls but have the potential for hugely variable lighting conditions. The excessive variability
of outdoor lighting limits useful profile creation to interior and in-studio camera work. If the lighting
conditions can be controlled adequately in the studio, then colour-accurate capture can take place and
colour accuracy can be maintained in the production work that follows.

Stabilizing a scanner’s performance comes from turning off any automatic adjustments for colour
correction:

• White and black point setting
• Removing colour casts
• Sharpening

If you can’t turn these off, then the scanner is likely not a good candidate for profiling. Optimize the
scanner’s behaviour with an output gamma setting of 2.6 to 3.0.

Stabilizing a camera’s performance comes from the appropriate lighting and capture settings. Use even
lighting and full highlight and shadow exposure for target capture. For colour temperature, use grey
balance for camera back devices, and white balance for colour filter arrays (CFA). Optimize the camera’s
bit depth retention with gamma 1.0 for raw profiling.

With calibration complete, it’s time to capture the target. For a scanner:

• Mount straight

• Mask open bed areas