Apple Aperture 3.5 - Manual (Page 285)

Chapter 7 Make image adjustments 285
3 Do one of the following:
•
To modify both the contrast and the tint in the image: Choose RGB from the Channel
pop-up menu.
Choosing the RGB tonal curve allows you to manipulate the tonal curve of the red, green, and
blue color channels combined.
•
To manipulate the luminance of the combined red, green, and blue channels without affecting the
tint: Choose Luminance from the Grayscale section of the Curves Action pop-up menu
.
4 Choose a tonal range display option from the Range pop-up menu:
•
To set the histogram and tonal curve to display pure black to pure white: Choose Normal.
•
To expand the histogram view to display pure black to two times pure white: Choose Extended.
Because some cameras are capable of capturing image information beyond pure white,
using the Extended range option provides controls for bringing that information into the
viewable image.
5 Choose the type of tonal curve adjustment to apply to the image from the Type section of the
Curves Action pop-up menu.
Choosing Linear—the default option—applies the Curves adjustment to the image evenly
from pure black to pure white and beyond. Choosing Gamma-Corrected applies the Curves
adjustment logarithmically to match the way the human eye perceives light, adding additional
weight to the shadows.
6 Drag the Black Point and White Point sliders to where they touch the outside of the histogram
graph, constraining the image to its new black and white points.
Drag the Black Point and
White Point sliders to where
they touch the outside of
the histogram graph.
67% resize factor