A

A channel, Decompose

absorption, How Colors Are Produced, The Subtractive Model

active channel, Overlaying Images, Components of the Layers Dialog

active layer, Hanging Drapes, Overlaying Images, 11.2 The Layers Menu, The Channels Dialog, 15.6 The Cloning Tools, Shared Properties, Modifying Frames, Playback and Navigator

Adams zone, Choosing a Format

adaptive supersampling, The Blend Tool, Gradient Flare

Add Alpha Channel, Morphing, Edge Detection Methods

Add Bevel filter, Adding a Frame with Filters, Using Layers, 4.1 Tutorial: Making a Luggage Tag, Weave

Add Border filter, Cropping an Image, Weave

Add Layer Mask feature, First Method: Selecting the Red Channel, Making a Photograph Look Older, Shading, Adding Relief and Proper Shade, Masks and Selections, 14.2 Layer Masks, Transparency and the Alpha Channel, Modifying Frames

Addition blending mode, Adding Relief and Proper Shade, Using Blending Modes, Lightening Modes

additive model, Image Preprocessing, Color Models, How Colors Are Produced, The Additive Model

Airbrush tool, The Paintbrush Tool, The Airbrush Tool, Trees, Paint Dynamics, The Eraser Tool, The Airbrush Tool, Spyrogimp

Alien Map tool, The Map Submenu

Align tool, Shared Properties

Alpha channel, Changing the Sky of a Landscape, Coloring the Mushrooms, Finishing Touches, Composition, Trees, River, Other Filters for Generating a Tilable Image, Constructing by Hand, 4.3 Logos, Generating a Cast Shadow, Generating a Cast Shadow, A Golden Logo, Masks and Selections, Digital Collage, Morphing, Edge Detection Methods, Components of the Layers Dialog, Components of the Layers Dialog, Components of the Layers Dialog, Components of the Layers Dialog, A Layer Entry in the Layers Dialog, 11.2 The Layers Menu, Color Models, Color Models, Levels, Levels, Levels, Decompose, Decompose, The Fuzzy Select Tool, 13.4 Using Selections, The Select Menu, The Channels Dialog, Building a Layer Mask, Manipulating a Layer Mask, Building a Natural Mask, Transparency and the Alpha Channel, Transparency and the Alpha Channel, Transparency and the Alpha Channel, Transparency and the Alpha Channel, Six Useful Dockable Dialogs, The Bucket Fill Tool, The Paintbrush Tool, The Eraser Tool, Filters, Destripe, Unsharp Mask, Curve Bend, Newsprint, Value Propagate, Perspective, Hurl, 17.8 The Generic Filters, GIMPressionist, Paper Tile, Plasma, IFS Fractal, Qbist, Morphing Text, Filtering All Layers, Netpbm Formats, Installed Plug-ins, 22.4 Building New Brushes, The Gradient Editor

(see also channels)

absent, Components of the Layers Dialog, Components of the Layers Dialog, 11.2 The Layers Menu, Color Models, 13.4 Using Selections, The Select Menu, Transparency and the Alpha Channel

adding, Changing the Sky of a Landscape, Other Filters for Generating a Tilable Image, Masks and Selections, Digital Collage, Morphing, Edge Detection Methods, Decompose, The Fuzzy Select Tool, The Channels Dialog, Morphing Text, 22.4 Building New Brushes

for anti-erasing, The Eraser Tool

forbidden, Destripe

in Checkerboard filter, IFS Fractal

in color brush, Six Useful Dockable Dialogs

in Convolution Matrix filter, 17.8 The Generic Filters

in Gradient Editor, The Gradient Editor

in Hurl filter, Perspective

in Newsprint filter, Newsprint

in RGB Noise filter, Hurl

initializing mask to, Finishing Touches

locking, Coloring the Mushrooms, Composition, Trees, 4.3 Logos, Generating a Cast Shadow, Components of the Layers Dialog, A Layer Entry in the Layers Dialog, The Bucket Fill Tool

present, Color Models, Levels, The Paintbrush Tool, Value Propagate, GIMPressionist, Paper Tile, Plasma, Qbist, Netpbm Formats, Installed Plug-ins

required, Building a Natural Mask, Unsharp Mask, Curve Bend, Filtering All Layers

thresholding, Transparency and the Alpha Channel

to layer mask, Building a Layer Mask, Transparency and the Alpha Channel

to logo, Filters

to selection, Constructing by Hand, A Golden Logo, Transparency and the Alpha Channel

unlocking, River, Generating a Cast Shadow, Components of the Layers Dialog

anchor button, Making a Photograph Look Older

anchor point, The Foreground Select Tool, Modifying a Path, Control Points

anchoring, Constructing by Hand, Overlaying Images, Digital Collage, 11.3 Layer Groups, 13.4 Using Selections

floating selection, Overlaying Images, 11.3 Layer Groups, 13.4 Using Selections

layer, Constructing by Hand

to layer mask, Digital Collage

Anim Preview dialog, Method Three: Moving Along a Path, Control Points

animated brush, Trees, Six Useful Dockable Dialogs, 22.4 Building New Brushes

animated GIF, Method Two: Filtering All Layers, Method Three: Moving Along a Path, Morphing, Frame Frequency and Vision, Spinning Globe, Optimizing and Playing an Animation, Converting Between File Formats

animations, Animation, JPEG, GIF, Compression

(see also frames)

answering curve, Correcting Colors, Levels, Curves, Color Management

(see also Curves tool)

anti-erasing, The Eraser Tool

Antialias filter, Tileable Blur

antialiasing, Drawing in GIMP, Drawing in GIMP, The Selection Tools Options, The Pencil Tool, Useful Image Map Dialogs, Common Options, Common Options, The Rectangle Select Tool, Using a Path, The Text Tool Options, Tileable Blur, Curve Bend, Newsprint, Polar Coordinates, Gradient Flare, Make Seamless, Gfig

in selection, The Selection Tools Options, Common Options

vs. feathering, Common Options

with Antialias filter, Tileable Blur

with Ellipse Select tool, The Rectangle Select Tool

with Emboss filter, Curve Bend

with Gfig filter, Gfig

with Gradient Flare filter, Gradient Flare

with Map Object filter, Make Seamless

with Newsprint filter, Newsprint

with Paintbrush tool, Drawing in GIMP

with Pencil tool, Drawing in GIMP, The Pencil Tool

with Ripple filter, Polar Coordinates

with Semi-Flatten filter, Useful Image Map Dialogs

with stroking, Using a Path

with Text tool, The Text Tool Options

Apply Canvas filter, Apply Canvas

Apply Lens filter, Unsharp Mask

Apply Threshold dialog, Touching Up the Panorama, Digital Collage

Area Settings dialog, Image Map

artistic filters, Depth Merge

aspect ratio, First Method: Selecting the Red Channel, The Rectangle Select Tool, Drawing Tool Options, Paint Dynamics, 15.6 The Cloning Tools, GIMPressionist

Assign ICC Color Profile dialog, Color-Managed Workflow

Auto button, Changing Brightness, Contrast, and Levels, Adjusting Colors, Modifying Brightness, Modifying Brightness, Correcting Colors, A Composite Photography Project, Dynamics Extension, Histogram Modification, Working with Multiple Images, Levels, Brightness-Contrast, Edge, Neon

auto shrinking, The Rectangle Select Tool, The Align Tool

autocropping, The Final Five Entries, Resizing an Image