Overview of Adobe Photoshop
Adobe Photoshop is a seriously powerful photo and image editing application. Part of theAdobe suite of productivity software, Photoshop is considered by many to be a benchmark in the world of professional digital image solutions.
The toolbox contains the main tools for working on images. Click any tool to select and use it.
A small arrow next to a tool in the toolbox indicates that the tool also has additional options available. In Photoshop, click and hold your mouse on a tool to see its options. For example, if you click and hold on the select tool, you'll see select options such as eliptical selction, single row selection, etc.
When you select a tool, additional options appear in the Tool Options bar (by default this is located just below the main menu). The example below shows the tool options bar when therectangular marquee tool is active.
Photoshop Marquee Select Tools
The marquee tools are selection tools which allow you to select rectangles, ellipses and 1-pixel rows and columns. The marquee tools are located at the top left of the PhotoshopToolbox. Click and hold your mouse over the marquee tool to see the four options:
Make a rectangular selection. Hold the shift key down to constrain the selection to a square. Note: ImageReady also allows rounded corners in rectangles.
Make an elliptical selection. Hold the shift key down to constrain the selection to a circle.
Single Row Marquee
Make a horizontal selection 1 pixel high.
Single Column Marquee
Make a vertical selection 1 pixel wide.
When you select any marquee tool, related options appear in the Tool Options bar (just below the main menu). This allows you to set the type of selection, feathering, etc. Options are slightly different for each marquee tool.
Photoshop Lasso Tools
The lasso tools allow you to select precise areas of an image by drawing or tracing the selection outline. There are three lasso tools available
This is a freehand selection tool. Click and hold your left mouse button on the image and draw your selection.
Polygonal Lasso Tool
Similar to the lasso tool, except that instead of holding your mouse button down to draw, left-click on various points to create a selection with a series of straight edges. You can also hold down the Alt key (Windows) or Option key (Mac OS) to draw freehand sections.
Magnetic Lasso Tool
This is a very handy tool for selecting areas which have reasonably well-defined edges. Left-click at the starting point of your selection and simply move the mouse along the edge.
"Fastening points" are automatically made at various points along the edges. Left-click at any time to add a fastening point manually.
To Complete a Selection
To finish drawing a selection, either click on the selection starting point or double-click anywhere.
Photoshop Crop Tool
The Crop tool allows you to select an area of an image and discard everything outside this area. The tool is located third from the top in the Photoshop Toolbox, on the left side.
Although cropping reduces the dimensions of an image, it is not the same as resizing. Whereas resizing reduces or enlarges the entire image and everything in it, cropping does not alter the size of the image content at all.
Using the Crop Tool
Select the crop tool in the toolbox. Select an area of the image to retain (just the same as making a normal selection). When you release the mouse button, the area to be retained is highlighted. This is what the new image will look like. You can move or transform the crop area by dragging the selection or the selection handles.
Hit your Enter key to perform the crop. The result of the example above looks like this:
Photoshop Healing Brush
The Healing Brush tool allows you to fix image imperfections such as scratches, blemishes, etc. By sampling the surrounding area or using a predefined pattern you can blend the imperfections into the rest of the image.
The healing brush tool is located in the Photoshop Toolbox, on the left side.
Using the Healing Brush Tool
Select the healing brush in the toolbox.
Check the settings in the options bar and adjust if necessary. Options include:
- Brush size
- Blending mode
- Source (Sampled from the image or pre-defined pattern)
Photoshop Clone Stamp Tool
Photoshop's clone stamp tool allows you to duplicate part of an image.
The process involves setting a sampling point in the image which will be used as a reference to create a new cloned area. Select the Clone Stamp tool, then check the settings in the options bar. Make sure you have a brush size appropriate for the job.
Photoshop Eraser Tool
Photoshop's eraser tool can be found in the second group of icons in the toolbox. It has three variations: Eraser, Background Eraser and Magic Eraser. The eraser is basically a brush which erases pixels as you drag it across the image. Pixels are erased to transparency, or the background colour if the layer is locked. When you select the eraser tool, you have various options available in the toolbar:
Brush: Options include the size of the eraser, hardness of edges and various styles. Brush options are not available in block mode.
Mode: There are three options: brush (soft edges), pencil (hard edges) and block (square brush size).
Opacity: 100% opacity erases pixels completely, 0% does not erase at all. 50% is semi-transparent (or coloured). Opacity is not available in block mode.
Flow: Determines how quickly the erasure is applied by the brush. Lower settings produce a more subtle effect. Only available in brush mode.
Airbrush: Use the eraser as an airbrush. Only available in brush mode.
Erase to History: Erases to a saved state or snapshot of the image. To use this feature, click the left column in the history palette next to the desired state.
Background Eraser Tool
The background eraser tool allows you to remove the background colour from an image or layer. When you click the image, the eraser samples the colour at the centre of the brush and erases this colour as you drag. Options in the toolbar allow you to specify the type of erasure, colour tolerance and sampling method.
Magic Eraser Tool
The magic eraser tool erases all colours within a set tolerance. This is essentially the same as using the magic wand and hitting Delete. Using this tool you don't need to drag — just click once.
Photoshop Move Tool
The move tool allows you to move a selection or entire layer by dragging it with your mouse or using your keyboard arrows keys. The move tool is located at the top right of thePhotoshop Toolbox. When the move tool is selected, click and drag anywhere in the image. By default, if an area is selected the selection will be moved, otherwise the whole layer will be moved. See the options bar for more options.
Alternatively, use your arrow keys to move the selection or layer in small increments. Hold down the Shift key to move in larger increments.
Note: You can activate the move tool when another tool is selected by holding down theCtrl key (Windows) or Command key (Mac OS).
Photoshop Magic Wand Tool
The Magic Wand tool allows you to select an area of an image based on its colour. The tool is located near the top of the Photoshop Toolbox.
When you click an area in an image with the magic wand, all areas which are a similar colour are selected. You can specify various options to determine the exact selection.
Using the Magic Wand Tool
Select the magic wand tool in the toolbox. In the options bar, select a Tolerance value (0 to 255). This determines how closely to match colours - higher tolerance means a larger selection.
- Check Anti-aliased to define a smooth edge to the selection.
- Check Contiguous to select only areas which are joined together.
- Check Use All Layers to select areas from all layers.
- Click the image in an area which you want to select.
Photoshop Slice Tool
The Slice tool allows you to divide an image into smaller sections which fit together like a jigsaw (but with straight edges). The slice tool is located in the top section of the Photoshop Toolbox.
There are two tools: Slice (which creates the slices) and Slice Select (which enables you to select and modify existing slices). Sliced images are commonly used for web design work, which sometimes requires images to be broken up in this way.
Using the Slice and Slice Select Tools
Select the slice tool in the toolbox.
Click and drag over the area you wish to make into a slice. Release the mouse button - Photoshop automatically creates the necessary number of slices, with the active slice highlighted. Using the slice select tool, you can move and resize slices by dragging inside a slice, or by dragging the handles.
The Brush Tool
The brush tool paints with smooth edges. The options bar looks like this:
Brush: The size of the brush.
Mode: The blending mode. For most work Normal will be the best option. Experiment with other modes to see what they do.
Opacity: Anything less than 100% will allow the underlying image to be seen.
Flow: Determines how quickly paint is applied. Lower setting produces lighter strokes.
The Airbrush Tool
The airbrush option allows you to apply gradual tones to an image, like a traditional airbrush.
The Pencil Tool
The pencil tool behaves much like the brush except that it has hard edges. The pencil tool options are the same as the brush tool, except: There is no airbrush option. There is an Auto Erase option. This paints the background colour over areas containing the foreground colour.
Photoshop Paint Bucket Tool
The paint bucket tool fills an area of an image based on color similarity. Click anywhere in the image and the paint bucket will fill an area around the pixel you clicked.
The exact area filled is determined by how similar each adjoining pixel is to the pixel you clicked on. You can adjust this setting in the options toolbar by changing the tolerance value (make sure the paint bucket tool is selected first). A low tolerance means only very similar colors will be affected, a high tolerance means more pixels will be affected. The range is 0 (exact color matches only) to 255 (all colors).
Fill: Foreground color (i.e. the currently selected color) or Pattern. If you select pattern, the next drop-menu becomes active and you can choose a pattern to use.
Mode: The same "blending modes" found in many other tools, including normal, dissolve, lighten, darken, etc.
Opacity: Set lower to make the underlying image partially visible.
Anti-alias: Make smoother edges by blending gradually with adjoining pixels.
Contiguous: (see below).
All layers: When using multiple layers, all layers are used to create the fill (otherwise only the selected layer is used).
When the contiguous checkbox is selected, only pixels that are connected to the original pixel are filled. The example below shows how this works. The image is clicked near the left hand side—first with contiguous on and then with it off:
Layers are a very important part of graphics work. If you have never used layers before, make the effort to learn how they work — you will probably find that it revolutionises the way you approach graphics and images. A photoshop image file (.psd) can be made up of numerous independent layers which are overlaid on top of each other. In the example shown here, a single image file is made up of three layers.
Any part of a layer which contains no image information is transparent, so layers below are visible in these areas. Each whole layer can also have different opacity settings, so some layers can be partially or completely transparent. The three layers in our example are a photograph, a lower third graphic and a text key. The chequered areas contain no information (so they are transparent).