- Simulation of darkroom (photography)
- Manipulating photgraphic images (different from Paint programs)

- Collage
- Pushing pixels around
- Everything digital imaging including color correction/grading

Compared to other tools, it is flexible/powerful but requires some understanding of

• Layering
• Masking

• Tools
  
  - Zoom (z)
  - Hand (h)
  - Rotate view (r). Hit 'esc' key to return to normal view
  - Crop (c)
  
  
• Commands
  - Cmd-0 to show full screen
  - Double click on zoom tool to show at 100% (pixel of image matches pixel of screen). A view without any artifacts.
  - f key - toggle between views (fullscreen, normal...etc)
  - tab key - show/hide tools
  

Apply a filter to an image Filter -> {Blur, Pixelate, Sharpen, Stylize}

Image -> Adjustments ...


Two problems

1. Filter applies to the whole image (solution: selection!)
2. Once you close the file, you can't undo the filter (solution: non-destructive editing!)

Layer -> New Adjustment Layer

You need to select so that you can say "this part". So that you can selectively apply effects (adjustment layers)

• because you want to change the color of the car
• because you want to select an image of a car and blur it so it looks like its moving at 200 miles/hour

You can select

• based on shapes you draw (square, rectangle, ellipse...etc)
• based on color - red area of the picture (magic wand)
  
  
• photoshop intelligence
• manual selection using paint brush

Now you can apply filters to your selection! But you usually want to turn your selections into layer masks

Destructive (cannot undo once you save the file) (Pre Photoshop 3.0-4.0)

• select, copy and paste
• select and apply filters or painting directly into the image

Non-destructive (undo-able and infinitely redo-able) (Since Photoshop 4.0 on)

• use layers
• select and use layer-masks (instead of cutting an image up)
• select and use adjustment layers (instead of directly changing the pixels)
• smart objects (somewhat higher abstraction - will make sense once you know adjustment layers well)

If you accept destructive editing, photoshop is a very simple tool. If you can't do non-destructive editing, you probably won't get a job.

Layer mask: A selection that is linked to layer and it's a non-destructive way to deal with images. As we will see later, selections (marching ants) and layer masks are interchangeable

• layer mask: black conceals, white reveals (and there are grays)
  
  
  
  
  
  
• Non-destructive Editing
  
  
  
  Non-destructive editing 1: Using layer masks to selectively apply an adjustment (adjustment layer)
  
  
  Non-destructive editing 2: Using layer masks to create a collage:
  
  

1. With selection (Marching ants), either

• Layer -> Layermask -> Reveal Selection
  
• click on "Add layer mask" button
  
  

2. selection automatically converted to layer mask




3. To create collage, duplicate the layers with layer masks to another document. Either

• Layer -> Duplicate Layers -> Destination: [document name]
• Drag and drop the layer into another document
  
  
  

Apple/Car/Moon





Turn the Car layer off but clicking on the eyeball icon





Drag the layer up and down to change the order

Car/Apple/Moon

Edit -> Free Transform
Edit -> Transform -> {scale, rotate, skew....etc...etc}

To complete the transformation, hit the return key

Blending mode




Opacity

If you want to paint into an image, rather than painting into a layer with an image, make an empty layer and paint into it.

Layer -> New -> Layer

Applying a filter is destructive. Duplicate the layer you want to apply the filter to so that you have a copy of the original

- Background layer (locked)
- move tool (v) to move
- Edit -> transform
- Grouping layers
- Flattening layers

• Add: Shift key
• Subtract: Option key
• ..or use the Option bar above to {add, subtract, intersect}
• Command-D: Deselect
• Command-Shift-D: Reselect
• Shift-select: constrained to square/circle
• Select -> Invert

Marquee tool [tool bar or keyboard (M)]

• drag the mouse to select a rectangular area
• hold shift to constrain to square

Lasso [tool bar or keyboard (L)] and Polygonal Lasso

• closes the selection when mouse is released
• hold option down: release the mouse button and makes a straight line (won't close the selection)
• straight line: option-click & click again at the end

Quick selection [tool bar or keyboard (w)]

• Photoshop intelligence at work

Magnetic lasso tool [tool bar or keyboard (L)]

• Click once along the edge of the object then follow the edge. photoshop automatically creates anchor points. clicking drops anchor points
• 'Delete' erases anchor points
• Lasso width (in options bar) determines how close (sensitive) the tool must be to select an object

Color range tool [Select -> Color]

• Select -> Color Range

Magic wand [tool bar or keyboard (W)]

• select area that has similar colors
• how similar? defined by "tolerance" in options bar
• 'contiguous' checkbox in options bar makes selection that is connected

Use the add (shift-click) and subtract (option-click) mode!!

• eg. select a large area with the lasso tool and subtract with magic wand..etc.

• Select -> Inverse
• Select -> Modify -> {Border, Expand, Contract, Smooth}
• Select -> Grow
• Select -> Similar
• Select -> Transform Selection

Layer Masks can be painted with a painting tool.

• Make sure you have the layer mask selected (the four corners around the layer mask icon).
• Using the brush as a selection tool!

Layer Masks can be filled with {black/white/gray} using selection tools

• Make sure you have the layer mask selected (the four corners around the layer mask icon).
• Select an area and then Edit -> Fill

Creating Empty/Filled Layer Masks:

• click on 'add layer' icon: (layer mask filled with white)
  
  
  
  
  
• option-click 'add layer' icon: (layer mask filled with black)
  
  

1. Turn the Apple red

2. Rotate the Apple to match the light source

3. Put the Apple in the Astronauts hand