GIMP Image Editing

Basic Edits

• Cropping (cut out region)• File format conversion

– 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] + ScrollZoom

• [SHIFT] + ScrollSide scroll

• [CTRL] + ClickToggle tool’s settings

(varies)

• [SHIFT] + ClickPaint 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

• Set perspective• Switch to cloning mode• Select clone source• Paint in new perspective• ???• Meh, whatever

Fine selection

• 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 distinctive-

colored 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 (Content-

Aware Resize)– Requires plug-in

Questions?