GS-PS: Color Balance, Foreground/Background Colors, and Color Picker

Review

• Feathering Selections
• Cropping
• Adjustment Layers
• Brightness/Contrast 

Adjustment Layers

• Adjustment layers are special layers that you can use along with several image editing commands, including Levels, Photo Filters, Hue/Saturation and others. Adjustment layers allow you to make non-destructive (editable) corrections to your images. For example, if you create a Levels adjustment layer, you can go back to the Levels dialog box later and change settings at any time. 
• To create an adjustment layer,  click on the adjustment layer button   at the bottom of the Layers palette, then choose one of the menu items (Levels, Curves, Color Balance, etc.).  Alternatively, you can choose Layer > New Adjustment Layer, and you will see the same menu of items. 
• The advantage of this over an ordinary Levels command is that the adjustment layer is fully editable. At any time, you can click the adjustment layer thumbnail  in the layers palette to edit the layer. When you do, the dialog box will reappear and you can change the settings. 
• Unlike ordinary layers, adjustment layers require minimal memory and do not significantly increase the size of the file.

Color Balance

• Colors are divided into channels with a slider for each. By adjusting the sliders you can control the color balance between Cyan and Red, between Magenta and Green, and between Yellow and Blue. The dialog further breaks things down loosely into Shadows, Midtones and Highlights. By selecting one of these under Tone Balance and then adjusting the sliders under Color Balance you can change the overall color of the image you are working on.
• At the very bottom of the dialog is a checkbox for "Preserve Luminosity." Keeping it checked is a good idea as this prevents the image from changing brightness (luminosity) as you adjust the color balance.
• Color Balance is generally best for trying to tweak the overall color of an image rather than correcting issues with parts of an image although you can use it with a layer mask or selection if you so choose. Be forewarned that the range of the color balance sliders is deceiving. It takes only a small change on the slider to change the appearance of an image. Don't overdo it or you will end up with strange results. It's all too easy to oversaturate the color you are trying to enhance.

Foreground and Background Colors

• The foreground color (the box shown in black in the toolbar screenshot to the left) is used by the current drawing tool – it's the active tool. The background color is used to fill in erased areas and to create gradient fills.
• To set the foreground and background to 100 percent black and white, click the small boxes next to the foreground and background color boxes in the Tool Palette. To switch the foreground and background colors, click the small arrows next to the foreground and background color boxes.
• You can choose new foreground and background tools by clicking once in either the foreground or background box to bring up the Color Picker.

Color Picker

• You can select a new foreground or background color by:

• Selecting it from the color box in the middle, sliding the arrows in the narrow color bar next to it to get a new color range. The color you select is displayed in comparison to the old color in two boxes to the right of the color boxes.
• Setting the HSB values (angle from 0 to 360 for hue, percentages of saturation and brightness).
• Setting the Lab values (Lightness values on the (a) green to magenta and (b) blue to yellow axes.)
• Setting the RGB values (values from 0 to 255 of red, green and blue).
• Setting the CMYK values (percentages of cyan, magenta, yellow and black). CMYK is the color mode used for print graphics.
• Set the hexadecimal value.

• At the bottom of the Color Picker you can limit your palette to only Web-safe colors by checking the box.
• Notice the two squares just left of the cancel button. The color shown on top is the currently selected color, the color on the bottom is the color you are replacing. If you see a triangle with an exclamation mark, it means you have selected a color that is out of gamut for CMYK. Below the out of gamut alert, Photoshop displays the closest color that is within the CMYK color gamut. If you see a small cube displayed, it indicates that the color selection is not "Web-safe." Below the Web safe alert, Photoshop displays a tiny swatch of the closest Web-safe color match. Clicking on either of the closest match swatches will change the selected color to the closest match.

GS-PS: Selecting Follow-up, Adjustment Layers and Type

Review

• Rectangle/Oval Selection Tools
• Lasso Selection Tool
• Polygon Selection Tool
• Magnetic Selection Tool
• Magic Wand Selection Tool

General Selection techniques

• To hide the selection outline, press Ctrl-H. To display the outline again, press Ctrl-H again.
• To invert a selection, choose Select > Inverse. Everything that was selected becomes masked, and everything that was masked now becomes the selection.
• To deselect, click outside of the selection, or choose Select > None.
• Shift + Rectangle/Oval Selection Tools create Square/Circle selections
• The choices on the Option Bar affects the sensitivity and behavior of many of the Selection Tools
• You can also save a selection (Select > Save Selection) for later use (Select > Load Selection).
• To move a selection outline, put the selection cursor on the edge of the selected area and drag.
• To move the contents of a selection, choose the move tool and drag the selection.
• To clone a selection, press Alt while using the move tool.
• To add to an existing selection, press Shift
• To subtract from an existing selection, press Alt
• To add to an existing selection based on color, choose Select > Similar.

 Cropping

• Choose the Crop tool () in the toolbox. Then click and drag across the image. An outline will appear that shows you the area to be cropped.

• Adjust the area to be cropped by using handles on the edges of the image. 
• Note: If you move the cursor just outside of one of the corner handles, it turns into a curved cursor, which then allows you change the alignment of the selected area. This is useful, for example, to correct a scan of a picture that was in a crooked position on the  scanner.
• Press Enter to crop or Escape to cancel

Feathering Selections

Feathering gives a selection a softer edge. You can feather a selection by entering a value in the Feather checkbox in the options bar. Or you can feather an existing selection by choosing Select > Feather.

Adjustment Layers

• Adjustment layers are special layers that you can use along with several image editing commands, including Levels, Photo Filters, Hue/Saturation and others. Adjustment layers allow you to make non-destructive (editable) corrections to your images. For example, if you create a Levels adjustment layer, you can go back to the Levels dialog box later and change settings at any time. 
• To create an adjustment layer,  click on the adjustment layer button   at the bottom of the Layers palette, then choose one of the menu items (Levels, Curves, Color Balance, etc.).  Alternatively, you can choose Layer > New Adjustment Layer, and you will see the same menu of items. 
• The advantage of this over an ordinary Levels command is that the adjustment layer is fully editable. At any time, you can click the adjustment layer thumbnail  in the layers palette to edit the layer. When you do, the dialog box will reappear and you can change the settings. 
• Unlike ordinary layers, adjustment layers require minimal memory and do not significantly increase the size of the file.

Brightness/Contrast

GS-PS: Selecting

Review of Layers

• creating
• transparency
• visibility
• locking
• ordering
• deleting
• copying

Selecting Parts of Your Image

• In some cases, you may wish to isolate part of an image for editing, or to combine it with other images. In Photoshop, this is called a selection.  When part of an image has been selected, the image editing tools and commands work the same way, but only the selected part of the image is affected. 
• When you make a selection, the part of the image that is protected (that is, not selected) is sometimes referred to as a mask.  Just as you might use masking tape to protect part of a wall when you are painting a room, in Photoshop you are masking the part of the image that you want to protect when you have selected part of an image for editing. 
• When you make a selection, a selection outline appears to show you the selected area. In the following example, a rectangular area has been selected:

• Note: In some cases, pixels may be partially selected (see feathering, below). In such a case, the selection outline is only approximate because there is no sharp boundary between selected and masked areas.

Using Selection Tools

• To make a selection, click a selection tool icon in the toolbox
• Take a look at the Options bar for the tool you are using. (If the options are not visible, choose Window>Options.) You may want to adjust the options for the tool (for example, to make the selection feathered). 
• In some cases, tools may be hidden "behind" other tools. Click and hold the tool to see the hidden tools.

Selecting Rectangles, Ellipses, and Rows: the Marquee tools

• The rectangular marquee tool ()   is probably the most frequently used selection tool. It allows you to select rectangular areas. Click and drag diagonally with it to make a selection.  
• The elliptical and row marquee tools are less frequently used. They are hidden "behind" the Marquee tool. 
• To select an elliptical area or a single row of pixels, type M to cycle through the marquee tools. Then drag (with Elliptical tool) or click (with Single Row tools) to make a selection.

Selecting Irregularly Shaped Areas: the Lasso Tools

• To create freeform selections, you can click and drag with the Lasso tool (). But the lasso tool may not give you enough control. For more control, you may find the polygon lasso and magnetic lasso tools easier to use. 
• The Polygon Lasso tool () is often quite useful for selecting irregularly shaped areas. To use it, click on the image, then move to another place and click again to create a segment. Click multiple times to create a selection around an irregular area in your image.  Double-click to finish the selection. Note: If you are in the middle of selecting and you make a mistake, press the backspace key to go back one segment, or click the Esc key to undo the selection entirely. 
• Without pressing the mouse button, move the magnetic lasso tool around an area to select it. The tool will look for edges. You can adjust its sensitivity to edges in the options bar.

Selecting by brightness and color: Magic Wand tool (W)

• Click somewhere on the image with the magic wand tool to select adjacent portions of the image based on color brightness. The higher the tolerance entered in the Options palette, the more pixels are selected.

GS-PS: Layers

Review

• Navigator Pallet/Hand Tool
• JPEG vs. RAW vs. PSD
• Undo vs. History Pallet vs. Revert
• Image Size
• Color Modes

Before You Begin to Edit

• It is always a good idea to keep your original image somewhere secure, as a backup, and work on a copy
• Always convert to .psd first, before beginning any editing

Layers

• Images in Adobe Photoshop are made up of layers. Initially, each image has only one layer (called the background layer), but you can add more layers to the image.
• Layers are very useful for editing images and creating special effects. For example, you could make a copy of a layer and make some changes to it. If you don't like the results, you can delete the layer and still have your original layer as a backup. You can also combine images by putting different content on different layers. 
• Note: Keep in mind that layers (except for adjustment layers) require a substantial amount of memory.  Photoshop files with large numbers of layers typically are large files.
• To work with layers, display the Layers palette by choosing Layers from the Window menu. The following is an example of the layers palette along with an image.

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  The first column of the layers palette shows which layers are currently visible, indicate by the eye icon ( ). In the above example all the layers are visible. You can change a layer's visibility by clicking the eye icon in the first column of the layer
  
  
  

  Note: Even when a layer is visible, part of it may be transparent. For example, this happens if you select part of an area and then press the delete key. When part of a layer is transparent, the layers underneath it can show through. Photoshop represents transparent areas by a checkerboard pattern:

  
  
  

  • You can change the opacity of a layer by entering a value between 0 and 100 in the Opacity field at the top of the layers palette. For example, at an opacity of 10%, the layer would be nearly transparent; at an opacity of 90%, it would be almost completely opaque. The opacity default is 100%.

  • Editing you do within Photoshop affects the current layer. In the example above, "Layer 1" is the current layer.

  • To make a layer the current layer, click on the layer in the Layers palette.
  • To change the name of the layer, double-click on the layer's name, then type in a new name.

  
  
  

  

  
  
  To lock (prevent changes to) a layer, click one of the Lock: boxes near the top of the layers palette. From left to right, they are: lock transparent areas, lock pixels (prevent changes to non-transparent areas), lock layer position, and lock all.
  Other actions can be performed by clicking on icons at the bottom of the layers palette:
  

  

  • To link two or more layers, first select them by shift-clicking on them in the layers palette. Then click the link layers icon. When they are linked they move together, so if you reposition a layer you will simpultaneously reposition all layers linked to it.

  • To add effects to a layer (for example, shadows), click on the layer styles icon.

  • To add an adjustment layer, click the Adjustment layer icon (adjustment layers are discussed below).

  • To create a new layer, click the new layer icon at the bottom of the Layers palette, or duplicate a layer by dragging the layer to the new layer icon.

  • To delete a layer, click the trash icon, or drag the layer to the trash icon (next to the new layer icon).