As photographers we tend to under-sharpen our images, which invariably
results in soft-looking prints lacking in fine detail. On the other hand
our friends (okay I'm stretching the friendly part) in the prepress
industry go the opposite direction and tend to over-sharpen; creating
crunchy images that are effectively impossible to re-purpose. So what is
it with sharpening digital images that causes both camps to get it so
wrong?
Sharpening is one of those necessary evils that digital imaging seems
to impose upon us. There are several, sometimes contradictory reasons for
this, but basically they fall broadly into two areas of the digital
workflow.
1. Capture
The process of capturing the image using a scanner or digital camera
will result in some softening of fine detail. Film grain, imperfect
optics, and the method of interpolating the missing colour data from
one-shot digital captures are only but a few examples for image
softening. This softening can't be avoided and in some cases may well be
a deliberate ploy on the part of the hardware vendor. To overcome this
we often find the scanner or camera software will include sharpening
features. Alas these tend to do more harm that good resulting in visual
artefacts that get worse rather than better as we begin the process of
editing the image.
2. Output
As with the capture process output devices will introduce some
softness. Remember we're turning pixels into dots of ink or dye will
introduce further softness. Each output process or media will have its
own limit on how much detail can be reproduced and so a fixed formula
will likely result in poorly optimised prints.
In effect we need to apply sharpening to overcome each of the problems
identified above. No problem you say, simply apply the appropriate amount
of Unsharp Mask (USM) in Adobe Photoshop and all will be well. Not so,
because what's good for one type of capture is often very bad for
another. Likewise the amount of sharpening required for an inkjet printer
will be very different from that required for an offset press.
Unfortunately the USM filter lacks the level of subtlety required by
many images and can often result in over-sharpening. When applied
globally it will help some areas and destroy others. Obviously there are
also many other sharpening techniques designed for localised sharpening
and each of them will have its niche. However, finding, understanding,
and finally optimising them to the particular needs of our capture and
output devices is easier said than done. Would't it be great if we could
have them all bundled together as a single solution? Well PhotoKit
SHARPENER is that solution.
With PhotoKit SHARPENER we have developed a highly optimised Adobe
Photoshop Automation Plug-in that provides for a 3-step sharpening
workflow. The workflow is simple in concept and splits sharpening down
into three easy to apply stages: Capture Sharpening, Creative Sharpening,
and Output Sharpening.
The advantages of PhotoKit SHARPENER include: non-destructive
sharpening with all effects being applied as Layers or Layer Sets,
default settings are designed with automation in mind thus minimising the
risk of user mistakes or oversight. Control is also provided via the
Opacity slider and allows the user to increase or decrease the amount of
sharpening at any time after the effect filter has been run.
PhotoKit SHARPENER is compatible with Photoshop 6, 7 and CS (aka
version 8). It will not work with Photoshop Elements or any other third
party image editing application. Furthermore, and as explained above the
PhotoKit effects are applied as layers, leaving the original image
untouched. This means that PhotoKit SHARPENER can only be used with 8-bit
per colour channel RGB mode images in Photoshop 6 and 7. Therefore it's
recommended that you carry out larger colour and tone edits on the
original 16-bit per colour channel RGB mode image before applying any
sharpening. However, there is no such limitation with Photoshop CS since
it fully supports 16-bit layers and blending modes.
PhotoKit SHARPENER comprises three menu options which are called from
the Photoshop File>Automate menu (see figure 1).
Figure 1
Once the user has satisfactorily completed the larger initial colour
and tone edits it's time to apply the first round of sharpening. Capture
Sharpening is designed to apply gentle sharpening early on in the
workflow and concentrates primarily in the midtones of the image.
PhotoKit Sharpener has a broad range of Capture Sharpener options
covering both film and digital type capture devices. The film sets are
resolution independent but it's still important to choose the correct
film format. Likewise with the digital capture devices the correct device
resolution should be selected. It's also recommended that pre-sharpening
or resizing of the image before this step is avoided.
Choosing the Capture
Device
Once the capture device type has been selected it only remains for you
to choose from one of three sharpening effects. These effects determine
to the extent to which edges are emphasised and the user manual provides
ample examples of where and when each should be applied.
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