Specifications
The Digital Fine Print Course
Viewing a Fine Print
Copyright Les Walkling 2012
45/50
Soft Proofing Light Sources
Soft proofing involves viewing, assessing and editing an image according to its appearance
on a monitor that has been accurately calibrated to simulate the viewing conditions under
which the finished print will be displayed.
The practice of accurately soft proofing images is highly desirable because it can lead to
increases in productivity, reliability and image quality. However it is a flawed concept. Of
the four common dimensions of an image, its colour gamut, tonal range, physical scale
and resolution, only the first three can be soft proofed with any certainty, and only then
if the image is no larger than the screen. The colour and tonality of the image can also
only be accurately soft proofed relative to the correlation between the monitor and the
print viewing conditions.
Ideally the monitor’s spectral distribution, density scale, and the ‘colour’ and brightness
of its white point should very closely match the viewing light’s spectral distribution, and
the density scale and paper white of the print under those viewing conditions. Therefore
the selection of a suitable print viewing light source is critical for soft proofing success.
Some light sources such as fluorescent lamps emit a discontinuous spectrum which can
limit the accuracy of the soft proof. Standard halogen lamps (around 3200ºK) emit an
excessively red spectrum. Hardware calibrating a monitor to such a low (reddish) colour
temperature is virtually impossible, and the required video card LUT adjustments would
significantly reduce its bit depth particularly in the blue and green channels, resulting in
lowered screen quality and even greater difficulty in accurately soft proofing the image.
5000ºK Monitor vs. 5500ºK Fluorescent 5000ºK Monitor vs. 4700ºK Solux vs. 3200ºK