Apple Macintosh PhotoFlash User Manual
Page 91
Some general guidelines for adjusting brightness and contrast follow step 3.
After you adjust the Brightness slider, click different areas of the image to
examine the changes in the brightest and darkest areas. If you move the slider
too far to the right, very light areas change to pure white and lose all detail. If
you move the slider too far to the left, very dark areas change to pure black
and lose all detail.
It’s also a good idea to examine the light and dark areas of the preview image
after you adjust the Contrast slider. If you increase contrast, lighter areas
become brighter and darker areas become darker. If you decrease contrast,
lighter areas become darker and darker areas become lighter.
3
When you’re ready to apply the new settings, click Enhance.
PhotoFlash applies the brightness and contrast settings you specified to the
frontmost window. If the window contains an image that includes a selection,
PhotoFlash applies the new settings to the selection only. If the window
contains a catalog with selected thumbnails, PhotoFlash applies the new
settings to the images they represent and ignores any selections the images
contain.
Every image you attempt to adjust with the Brightness/Contrast command is
likely to require slightly different settings for optimal quality. Finding the
right settings is usually a matter of trial and error, but keep these guidelines in
mind as a starting point for your adjustments:
If the image appears to be
m
too dark,
increase the brightness and then experiment with changing
the contrast.
m
too light,
decrease the brightness and then experiment with changing
the contrast.
m
too gray
, increase the contrast and then experiment with changing
the brightness.
m
too high contrast
, decrease the contrast and then experiment with changing
the brightness.
If you can’t improve an image by adjusting its brightness and contrast, try the
Balance Exposure command.
81
Enhancing Images