AV News 200 - May 2015
Saving your own Presets can be useful if you have a series of images taken
under similar circumstances which require the same level of exposure
correction. Adjusting exposures may be achieved by simply sliding the bars or
by entering numerical values in the appropriate boxes, although it's easier to
use the sliders. Sliding e ither the Exposure or Offset bars to the right lightens
the overall image comparable to overexposing a transparency film. Sliding left
darkens the image comparable to underexposing a transparency. Conversely
sliding the Gamma bar right darkens the image and sliding left lightens and
softens the image contrast. If the Preview box contains a tick then the effects
of sliding any bar can be seen in real time, therefore it's easy to assess visually
the amount of correction applied.
It may surprise some readers that it's just as important at the taking stage not
to overexpose digital images as it was with transparencies. Overexposure
causes blocking of fine or
subtle detail in highlight areas.
Post exposure it may be that
your image doesn't need
overall correction of exposure
i.e. lightening or darkening of
the whole image, but it may
require subtle adjustments to
the highlight or shadow areas
whilst leaving other areas unaffected. In such circumstances Photoshop
provides another very useful tool named 'Shadow/Highlights'. This is accessed
from the main menu by clicking 'Image', 'Adjustments', then click on
'Shadow/Highlights'. Initially a small control panel opens showing just two
adjustment bars, one for
Shadows and the other for
Highlights. Place a tick in the
small 'Show More Options' box,
this control panel then expands
to show a much more
comprehensive list of controls. At
the top of this expanded control
panel sits three slider bars used
to control 'Shadows', these are
named 'Amount', 'Tone', and
'Radius'. By default 'Amount' is
set to zero, 'Tone' is set central at
50%, and 'Radius' is usually set
to 30 pixels. In the middle portion
of the control panel sits a similar
set of slider controls used for
adjustment to Highlights, names
for these sliders and value
settings are the same as those
used for 'Shadow' sliders.
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