GIMP Image Editing
Basic Edits
• Cropping (cut out region)
• File format conversion
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JPEG/PNG/GIF
Native XCF format
Supports .psd (Adobe)
Others…
• Rescale/Rotate (layers)
• Add caption (see text)
• Remove ex-girlfriend?
Starting up the GIMP
• Toolbox (extra by default)
– Basic tools found here
• Image pane
– Advanced tools in menus
– New/Save
• Set dimensions, mode,
etc.
• Export in 2.8
– Single-window option in 2.8
• Layers, Channels, Paths,
Undo
Some useful shortcuts
• [CTRL] + Scroll
Zoom
• [SHIFT] + Scroll
Side scroll
• [CTRL] + Click
Toggle tool’s settings
(varies)
• [SHIFT] + Click
Paint in straight line
• Hover + [F1]
– GIMP Help Browser
• [SHIFT] + Select
– Add to selection
• [CTRL] + Select
– Subtract from selection
• [CTRL] + [SHIFT] + Select
– Select intersection
• Standard Windozey
bindings
Text (Type) Tool
Text (Type) Tool
• Click to type
• Set font/style in toolbar
• Either highlight to change, or
set font/size/style before
typing
• Editor opens in new window
– This is fixed in 2.7/2.8
• Outline a bit more involved
– Path from text, stroke path
Painting
• Not MS Paint…
– But it can compete
• Paintbrush/Pencil/
Airbrush
– Brush types
• Fuzzy/Fine
• Custom brushes
• Rotating in 2.8
• Fore/Background
color
• Bucket fill
Patterns & Gradients (l)
• Fuzzy vs. Fine
brushes
– Custom brushes
• Paint with
pattern/gradient
• Gradient tool
– Fill entire selected
region
– MANY advanced tricks
use this
• Think mathematically
Dodge/Burn (D)
• Selectively
lighten/darken with
paintbrush
– Different from painting
• Lighting effects
– Similar to photography
• Useful for contrast,
emphasis,
highlighting
https://en.wikipedia.org/wiki/File:DodgeBurn.png
Smudge/Blur (s/U)
• Selectively blur or rub
as oil painting
– Similar to smearing
paint with finger
– Useful for censorship,
emphasis, painting-like
effect
• [CTRL] + click for
opposite effect
• Useful for texture,
esp. faces
Cloning/Healing Comparison
• Clone Stamp is most
common
– Duplicating patterns
• Paint from clone source
– Removing sections
• Healing (Brush) more
specialized
– More gradual
• Takes surrounding region
into account
– Removing blemishes
– Smoothing small regions
Guide to Cloning/Healing
• Select clone source
[CTRL] + click (origin)
• Paint anywhere using
origin as palate
– Origin moves with
brush as you paint
• ???
• PROFIT!!!
Perspective Cloning (?)
• Just like cloning
– but with perspective
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Set perspective
Switch to cloning mode
Select clone source
Paint in new perspective
???
Meh, whatever
Fine selection
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Paths tool (?)
“Intelligent” Scissors (magnetic lasso)
Fuzzy Select (magic wand)
Quick Mask (?)
Grow/Shrink/Feather
Paths (b)
• Useful for curved but
continuous selection
• Also curves in general
• Select multiple points
• Move/Resize vectors
to adjust curves
• Create near full circle
(no intersections)
• Select  From Path
• GIMP is not a
vector program
• But it can use
vectors
Intelligent Scissors
• Easier, faster, more
robust, dynamic
• Not always better (see
Rainbow Dash)
• Select key points
• More the merrier
• Linear path finding w/
graph theory
• Close loop, then adjust
• To finalize, click inside
selection
Fuzzy Select (u) (Magic Wand)
• Similar-colored
surrounding regions
– Only contiguous
• Move mouse up/down
to adjust sensitivity
– Set default threshold
• Ideal for selecting
multiple regions
COlor Select
• Similar-colored regions
– Entire image
• Move mouse up/down to
adjust sensitivity
– Set default threshold
• Also ideal for selecting
multiple regions
– Preferable for distinctivecolored parts
Refining your selection
• Quick Mask ([SHIFT] + Q)
– Red overlay not selected
– Paint/Erase selection
• Select  Grow/Shrink
• Select  Feather
(blur)
• Shapes (rectangle,
elipse, freehand)
– Rounded corners
– Feathered edges
– Guides
Layers
• Stacked in one image
• Opacity & sizes
• Edit one at a time
– Preserve others
• Copy/Delete/Create,
Insert
• Used for animated
GIFs
• Layer grouping in 2.8
Modes, Masks, Transparency
• RGB, greyscale, indexed
(image as a whole)
• Alpha channel
– 24-bit vs. 32-bit
• Layer mask
– Black = 0 = transparent
White = 255 = opaque
– Black background and
colorful foreground gives…
Move/Resize/Transform
• Layers as their own
independent images
• Perspective ([SHIFT] + P)
• Filter  Distort  iWarp
– Cage transform in 2.8,
improved in 2.10
• Rotate/Resize/Flip
([SHIFT] + R/T/F)
• Move layer or selection
• Liquid Rescale (ContentAware Resize)
– Requires plug-in
Questions?