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).

GS-PS: Core Concepts for Image Quality

Review

• Menu Bar
• Status Bar
• Pallets
• Tool Bar
• Image Window
• Zoom Tool
• Hand Tool

Navigator Pallet + Hand Tool

• When using another tool, you can press the spacebar to temporarily access the hand tool. You can then drag to move around the image. When you stop pressing the spacebar,  you will return to using the other tool.
• To zoom and move around the image with the Navigator palette, choose Window>Show Navigator. The navigator palette will appear:

Use the navigator palette to zoom in or out of an image (by dragging the navigator slider) or to move around the image by dragging the view box (when you are zoomed in). The view box (red box in the above example) shows the part of the image that is currently being displayed in the main image window.

JPEG's vs. RAW vs. .PSD's

• Always try to take images in RAW format if you camera allows it.
• If you have a RAW image, you can do some editing before you import the image, then save the file as a .psd
• If you have a .jpg/.jpeg, you should immediately save it as a .psd before doing anything else.

Correcting mistakes and History Palette

• Choose Edit-Step Backward to undo your last action.
• Choose Window-Show History to view the History palette. Then you can click on a previous history state to undo one or more of your actions.
• Choose File-Revert to return to last saved version of file.

Getting Help

To access online help, choose Help > Photoshop Help.

Image Size

• Digital images are made up of pixels (picture elements), which can be defined as colored squares. Each pixel is only one color.
• A good way to learn about image size, resolution, and print size is to experiment with an image using the Image Size dialog box.  To do this, open an image in Photoshop. Then choose Image > Image Size, and the Image Size dialog box appears.
• 
• Under Pixel Dimensions, Width and Height refer to the number of pixels in an image, which has to do with the size of display on screen.
• Under Document Size, Width and Height refer to the size of the image when printed.

Experimenting with Document Size Options

• Uncheck Resample Image and change the resolution to 300 ppi. (high quality printing)  
• Note what happens to your document size numbers
• To change the print size of an image, uncheck the "Resample Image" box.  When you turn resampling off, notice that the Pixel Dimensions are no longer editable.
• Under Document Size, there is a trade off between Width/Height and the Resolution. If you increase the width and height, resolution decreases. If you increase the resolution, width and height decrease. 
• As a general guideline, newsletters and newspapers are likely to require resolutions in the range of 150 to 200 ppi, and magazines are likely to prefer high resolution images of 250 ppi or more. 
• A resolution of more than 300 ppi may be unnecessary. But keep in mind that if you crop the image and then enlarge the cropped image to the size of the original, the resolution will be lower than the original... so an image that was 300 ppi, then cropped and enlarged, may then be much less than 300 ppi.

Color Modes

• In Photoshop, you are always working in a color mode. The default mode is RGB (Red-Green-Blue), which is also the default mode for the Web. If you are only working to create color images for the Web or for a desktop inkjet printer, you may not need to use any of the other modes. But it is useful to know about modes because this gives you a better idea of how Photoshop creates, displays and prints images.
• Each color mode defines the colors that combine to make up the color of every pixel in the image. To change color modes, choose Image > Mode.
• Color modes are made up of channels. Each channel is a grayscale image. A grayscale image is an image made up of shades of brightness (as many as 256 shades, from white to black). To view the channels, choose Window > Channels, and the Channels palette will appear. Modes with fewer channels result in smaller file sizes.
• For example, in RGB mode, the red channel is a grayscale image made up of brightness values for the color red; the green channel is made up of brightness values for the color green; and the blue channel is made up of brightness values for the color blue. Each pixel in the full color image is made up of a combination of of brightness values for red, green, and blue.
• Note: It is possible to edit an individual channel, which is useful to improve the quality of some images.

Some of the most frequently used color modes are:

RGB mode three channels (Red, Green, and Blue) used by all monitors and by the Web recommended by Adobe for editing color images

Grayscale mode One channel, 256 shades of gray

Bitmap mode black and white (no shades of gray) used for line art

Indexed mode one color channel, up to 256 color values used for GIF images destined for the Web

CMYK mode

• four channels (Cyan, Magenta, Yellow, Black)
• used by professional printing houses. If you are producing a images for a publication or poster, you may need to save it in CMYK mode.

Core Concepts for Photoshop

1.  .psd is lossless.  .jpg is lossy.  Always convert jpg's to .psd's before doing anything
2. create a new (duplicate) layer before you get started by dragging the background layer to the New Layer icon.  You can then poke out the eyeballs of the background layer and get to work
3. Always create Adjustment Layers, don't adjust the image itself
4. Print/export from the .psd file, if possible, don't convert to another file format unless necessary.  And, if you have to, do it last
5. Create "Comps" as you go for states that you like - layers/layer options/edits... frozen

GS-PS: Getting Started

When you open Photoshop, the Photoshop desktop appears.

Components of the Photoshop desktop include the menu bar, image window, toolbox, status bar, and palettes. 

The Menu Bar

The menu bar, at the top of the Photoshop desktop, includes several dropdown menus for choosing commands. Right below the menu bar, options for the currently-selected tool are displayed (see  Toolbox tools, below).

Image Window

The image window displays the current image. The name of the image file appears at the top edge of the image window. If rulers are turned on, they appear at the top and left edges of the image window. To display or hide rulers, choose Ctrl-R or View>Rulers.

About Rulers: Rulers show the size of your image. To change the unit of measurement (such as from pixels to inches), double click on the ruler, or go to Preferences (Edit>Preferences>Units & Rulers).  If you are creating an image for the Web, use pixels as the unit of measurement. 

The Toolbox

The toolbox contains tools for working with images in Photoshop. Only one tool is selected at any given time. To select a tool, click on its icon in the toolbox.

Some important tools are briefly described below. Toolbox tools are used for most Photoshop tasks and we'll spend a lot of time in other classes going over how to use particular tools.

The Status Bar

The status bar at the bottom of the Photoshop desktop provides information about your current view and other information that you can specify by choosing from a dropdown menu (in this example, the view is now 33.33% and the document dimensions are 8.371" x 8.371").

Palettes

Palettes enable you to perform a wide variety of tasks in Photoshop. To display or hide particular palettes, go to the Window menu and choose a palette name.

Palettes are usually organized into groups. In the above example, Layers, Channels, and Paths are a group.  You can easily move a palette group by dragging its blue bar (at the top of the group). To shrink a palette group, double-click on its blue bar. To hide a palette group, click its close box (the "X" on the right side of the blue bar).

You can drag the tabs of palettes to move them around, or to combine them into other groups.

To reset palette locations to the default, choose Window>Workspace>Reset Palette Locations.

When you first launch Photoshop, the Photoshop desktop (described above) appears. But in order to do anything, you need to have an image. There are four main ways you can bring an image into Photoshop:

• You can open an existing image file by choosing File > Open or File>Browse. This would include images you have downloaded to your computer from a digital camera or from the internet. Photoshop can open most image file types.
• If your computer is connected to a scanner with a Photoshop plug-in that has been properly installed, you can scan an image into Photoshop by Choosing File > Import.
• You can create a new Photoshop file from scratch.

When editing images, you can do many tasks more effectively if you zoom in and move around the image. Zoom in close to make adjustments to small areas, then zoom back out to see how your edits have affected the overall image.

The main tools for zooming and moving around an image are the zoom tool, the hand tool, and the navigator palette.

• To zoom in, choose the Zoom tool ( ) and then click or click and drag in the image.
  
  When you zoom in, the zoom percentage (or view size) increases. The current zoom percentage is shown in the status bar and at the top of the image window. The zoom percentage shows the magnification at which you are viewing the image (not the actual size of the image).
  
• A quick way to go to 100% view size is to double-click on the zoom tool icon in the toolbox.
• To zoom out, press the ALT key while you click with the zoom tool.
• Use the Hand tool () to move around the image in the window when you are zoomed-in.

Displaying and hiding palettes and the toolbox

• Press Tab to hide palettes and toolbox.
• Press Shift-Tab to hide palettes.