Adobe After Effects CS3 - Manual (Page 401)

AFTER EFFECTS CS3
User Guide
396
Blend With Original The effect’s transparency. The result of the effect is blended with the original image, with the
effect result composited on top. The higher you set this value, the less the effect affects the layer. For example, if you
set this value to 100%, the effect has no visible result on the layer; if you set this value to 0%, the original image doesn’t
show through.
Curves effect
The Curves effect adjusts the tonal range of an image. You can also use the Levels effect, but the Curves effect gives
you more control. With the Levels effect you make the adjustments using just three controls (highlights, shadows,
and midtones), but with the Curves effect you can arbitrarily map input values to output values using a curve defined
by 256 points.
You can load and save arbitrary maps and curves to use with the Curves effect.
This effect works with 8-bpc, 16-bpc, and 32-bpc color.
When you apply the Curves effect, After Effects displays a graph in the Effect Controls panel that you use to specify
a curve. The horizontal axis of the graph represents the original brightness values of the pixels (input levels); the
vertical axis represents the new brightness values (output levels). In the default diagonal line, all pixels have identical
input and output values. Curves displays brightness values from 0 to 255 (8 bit) or 32768 (16 bit), with shadows (0)
on the left.
John Dickinson provides visual aids on his website that illustrate how to use the Curves effect for color adjustments:
www.adobe.com/go/learn_ae_jdcurves .
Use the Curves effect
1 Choose Effect > Color Correction > Curves.
2 If the image has more than one color channel, choose the channel you want to adjust from the Channel menu.
RGB alters all channels using a single curve.
3 Use the Bezier tool and the Pencil tool to modify or draw a curve. (To activate a tool, click the Bezier button
or the Pencil button .)
To smooth the curve, click the Smooth button. To reset the curve to a line, click the Line button.
The curve type is determined by the last tool used to modify it. You can save arbitrary map curves modified by the
Pencil tool as .amp (Photoshop lookup) files. You can save curves modified by the Bezier tool as .acv (Photoshop
spline) files.
Equalize effect
The Equalize effect alters an image’s pixel values to produce a more consistent brightness or color component distri-
bution. The effect works similarly to the Equalize command in Adobe Photoshop. Pixels with 0 alpha (completely
transparent) values aren’t considered, so masked layers are equalized based on the mask area.
This effect works with 8-bpc color.