Essentially color management is concerned with describing the characteristics of each device in the editing chain. This includes cameras, scanners, screens, editing software and printers.

This description, often called an ICC profile, is then used to translate image detail and color from one device to another.

Pictures are tagged, when they are first created (via camera or scanner), with a profile and when downloaded to a computer, which has a profiled screen attached, the image is translated to suit the characteristics of the monitor.

With the corrections complete the tagged file is then sent to the printer, where the picture is translated again to suit the printer’s profile.

Through the use of a color-managed, ICC profile-based system we can maintain predictable color throughout the editing process and from machine to machine.

A file with the same pixel dimensions can have several different document sizes based on altering the spread of the pixels when the picture is printed (or displayed on screen). In this way you can adjust a high-resolution file to print the size of a postage stamp, postcard or a poster by only changing the dpi or resolution. This type of resizing has no detrimental quality effects on your pictures as the original pixel dimensions remain unchanged.

This said, in some circumstances it is necessary to increase or decrease the number of pixels in an image. Both these actions will produce results that have less quality than if the pictures were scanned or photographed at precisely the desired size at the time of capture.

As this isn’t always possible, Photoshop can increase or decrease the image’s pixel dimensions using tools such as the Image Size or the Scale features. Each of these steps requires the program to interpolate, or ‘make up’, the pixels that form the resized image.

Interpolation is a process by which the computer program reduces or increases the number of pixels in the picture. To achieve the color and brightness levels pixels are averaged and used as a basis for creating new pixels according to a specific algorithm. When resizing pictures in Photoshop you can select from several different interpolation algorithms (1). These options are available in the Image Size feature.

One measure of digital image quality is the resolution of the picture which is usually stated in pixels per inch (ppi).

The more pixels per inch the higher the resolution. Not to be confused with sharpness, which is affected by a number of things, including lens quality. The resolution needs to be high enough to suit the viewing media and should not be confused with dpi (dots per inch).

If, for example, you only ever look at the images on a computer monitor for Web use you only need a resolution of 72 ppi for Macs and 96 ppi for a PC and each pixel will be displayed as a dot. If, on the other hand, you’re wanting to send the images to a magazine or book publisher you’ll need a resolution of at least 300 ppi, whilst most desktop inkjet printers require files with 150 to 240 ppi and lay down several dots per pixel to ensure accurate colors.

Russell Brown developed the Image Processor to demonstrate the power of the scripting engine within Photoshop and at the same time to provide a very handy image conversion utility. The feature is designed to quickly convert a range of Raw files into JPEG, PSD and TIFF versions. There are options to manually adjust the conversion settings for the first file and then apply these settings to the rest and the ability to apply an action during the process.

The Image Size dialog provides several options for manipulating the number of pixels in your photograph and how big it prints.

At first glance the settings displayed here may seem a little confusing, but if you can make the distinction between the Pixel Dimensions of the image (1) and the Document Size (2), it will be easier to understand.

Keep in mind:

Pixel Dimensions represent the true digital size of the file.

Document Size is the physical dimensions of the file represented in inches (or centimeters) based on using a specific number of pixels per inch (resolution or dpi).

To keep the ratio of width and height of the new image the same as the original, tick the Constrain Proportions checkbox (3).

To change resolution, open the Image Size dialog and uncheck the Resample Image option (4). Next, change either the resolution, width or height settings to suit your output.

To increase the pixels or upsize the image, tick the Resample Image checkbox (4) and then increase the value of any of the dimension settings in the dialog. To decrease the pixels or downsize the image, decrease the value of the dimension settings.

The Image, or Source, Space refers to the ICC profile that a picture has been tagged with. The profile might have been attached at the time of capture or added later but it is this image space profile that allows the image to be correctly displayed and printed.

So when shooting make sure that any color management or ICC profile settings in the camera are always turned on (1). This will ensure that the pictures captured will be tagged with a profile. Those readers shooting film and converting to digital with scanners should search through the preference menus of their scanners to locate, and activate, any in-built color management systems here as well. This way scanned pictures will be tagged as well.

Next, to ensure that Photoshop is correctly using the image space, make sure that the most appropriate option (2) for your situation is selected in the Color Settings dialog of the program. This ensures that tagged pictures coming into the workspace are correctly interpreted and displayed ready for editing and enhancement. When it comes time to print select the File > Print with Preview option and then Let Photoshop Determine Colors and finally input your Printer Profile before pressing Print to finish (3).

ImageReady is a Web image editing program that’s bundled with Photoshop. It has the same interface and allows seamless connection from within the program. We saw a jump from version 3.0 with Photoshop 6.0 to version 7.0 with Photoshop 7.0. Now it follows suit with ImageReady CS. The program allows you to slice a picture up so that it can be used more effectively on a Web page. You can also optimize pictures, create rollovers and edit animation. CS2 now includes features such as the Animation palette that started life as an ImageReady feature.

The Import menu located under the File heading lists a range of sources for importing images into Photoshop. Acting much like the Import TWAIN feature found in older software, the feature links installed cameras and scanners with Photoshop and allows the user to control the driver software from inside the editing package.

The import sources listed under the menu normally include the following:

Installed scanners/cameras – Use the scanner driver or camera download software to import pictures from either of these device types.

WIA Support – Most cameras that are designed to connect to Windows computers are supplied with a WIA or Windows Image Acquisition driver that is used for downloading pictures from these devices.

Annotations – This option allows you to import annotations that have been saved in PDF or FDF file.

Variable Data Sets – Use this selection to import text-based data sets to be used when generating data driven graphics.

Note: The exact contents of the import menu list are determined by the scanners or cameras that you have installed on your computer.

The Indexed Color mode can support up to 256 different colors and is the default color mode for the GIF file format.

When a full color picture is converted to the Index mode the colors used are drawn from a special palette (1). They are:

Exact – For pictures with 256 colors or less where the exact colors are used in the converted file.

System (Mac OS) and System (Windows OS) – Use the system palette.

Web – Uses a special set of 216 colors that can be displayed by all computer systems.

Uniform – Uses a palette of colors that have been evenly sampled from the RGB color space.

Perceptual – Uses a color set that gives priority to colors that the human eye is more sensitive to.

Selective – Similar to perceptual but also favors the web color set.

Adaptive – Builds a set of colors from those most present in the original picture.

Custom – Create your own palette of colors using the Color Table dialog box.

Previous – Uses the previous custom palette.

The dialog also has options to allow you to select the total number of colors to present in the final conversion, force specific colors to be included, add transparency, select a matte color and choose a dither type (2).

The Info palette provides a variety of information about the open document. With the palette displayed, moving a tool pointer over the canvas surface will show details of the pixels beneath the tool tip. The details are displayed in five sections of the palette:

(1, 2) First and second color readouts displayed in Grayscale, RGB, WEB or HSB color.

(3) Mouse coordinates displayed in pixels, millimeters, centimeters, inches, points, picas or percent.

(4) Width and height of marquee displayed in pixels, millimeters, centimeters, inches, points, picas or percent.

(5) File information such as document size, profile or dimensions and scratch sizes, efficiency, timing and current tool.

The units used for each display section are set via the pop-out menu (6) displayed when the More button (top right) is pressed.

The Ink Outlines filter, as one of the group of Brush Strokes filters, draws fine black ink lines over the edge details of the original picture.

Three controls in the filter’s dialog allow adjustment of the filtering process and results.

The length of the stroke used in the outlining process can be varied with the Stroke Length slider (1).

The Dark Intensity (2) and Light Intensity (3) sliders provide control over the brightness and contrast of the final result. When low values are used for both sliders a low contrast picture results. Conversely higher settings produce a more contrasty result overall.

The Levels feature controls image tones in two different ways. The upper sliders (the ones just below the histogram graph) alters the input levels (1) of the picture and are most often used to increase the contrast of low contrast picture. The example image shows the increase in contrast that is possible when you drag the black (left) and white (right) input sliders in towards the center of the graph until they reach the first groupings of pixels (3).

The slider at the bottom of the Levels dialog controls the output levels of the image (2).

In Photoshop CS2 you can customize the user interface more than in any other version of Photoshop.

You can select, manage and save your own keyboard shortcut schema quickly and easily with the options in the new Keyboard Shortcuts and Menus dialog (1) located in the Window > Workspace menu. Apart from allocating specific keystroke combinations to particular tools, menus, features and actions, the options in the Menus tab control the color and visibility of different menu entries (3). After adjusting the settings the final workspace schema can be saved off and distributed to others to use. Customized workspaces can be imported and added to the list of presets that ship with Photoshop using options in the same dialog. You can then select from the schema that are installed via the entries in the Window > Workspace menu (2).

The size of the font used in the Photoshop Interface can also be changed using the setting in the General section of the Preferences dialog (4). Three sizes are available – small (5), medium (6) and large (7).

If you change the size of a digital file your software either adds pixels when increasing the size or removes them when making the image smaller.

This process is known as Interpolation and relies on Photoshop knowing which pixels to add or dump.

There are now five methods of interpolation in Photoshop – Nearest Neighbor, Bilinear and Bicubic, with Bicubic Smoother and Bicubic Sharper which were first added in Photoshop CS.

The default method used by Photoshop when changing image sizes can be set by going to Edit > Preferences > General.

Nearest Neighbor offers the fastest method by copying the adjacent pixels, but results are often poor. Bilinear looks at pixels above and below plus left and right and averages out the result to give an intermediate pixel and a smooth blend. It’s slower than Nearest Neighbor, but not as slow as Bicubic which looks at all the pixels surrounding each pixel and averages them all out to create the new ones. It then boosts contrast between each pixel to reduce softness. Bicubic Smoother is used when you enlarge the image and Bicubic Sharper when you reduce the image.

The Image Size feature uses interpolation in the changes it makes to picture dimensions. The feature’s dialog contains a drop-down menu where you can select the interpolation method used when processing the changes.

This command makes a new selection by choosing all the pixels in the picture that are currently not selected.

When trying to select a subject that has a complex edge but a plain background, try selecting the background first (1) with a tool such as the Magic Wand or Color Range feature. Next swap the selection from the background to the foreground using the Select > Inverse option (2).

The Invert adjustment reverses all the tones and colors in the picture, creating a negative effect.

No controls are available for the user to adjust the strength or style of the effect. The feature changes are applied immediately after the entry is selected from the menu.

The Invert adjustment layer produces a negative version of your image. The feature literally swaps the values of each of the image tones.

When used on a grayscale image the results are similar to a black and white negative. However, this is not true when applied to a color picture as the inverted image will not contain the typical orange ‘mask’ found in color negatives.

Manipulating the picture with an adjustment layer rather than directly means that the original picture is always kept intact and you can always remove the effect by deleting the adjustment layer.

One feature of the new Reduce Noise filter is the option to smooth out the box-like appearance of JPEG artifacts.

One of the side effects of saving space by compressing files using the JPEG format is the creation of box-like patterns in your pictures. These patterns or artifacts are particularly noticeable in images that have been saved with maximum compression settings.

With the Remove JPEG Artifact option (1) selected in the Reduce Noise dialog, Photoshop smooths out the box-like pattern created by the overcompression.

JPEG is a file format designed by the Joint Photographic Experts Group to use with pictures destined for the web or e-mail.

This format provides high levels of compression for photographic images. For instance, a 20 Mb digital file can be compressed in the JPEG format so that it can be e-mailed quickly and easily to anywhere in the world.

To achieve this level of compression the format uses a lossy compression system, which means that some of the image information is lost during the compression process.

In Photoshop, pictures can be saved in the JPEG format via dialogs in the Save As or Save for Web commands. The amount of compression is governed by a slider control (1) in the dialog box. The lower the number or the smaller the file, the higher the compression and more of the image will be lost in the process. You can also choose to save the image as a standard ‘baseline’, optimized or progressive image (2). This selection determines how the image will be drawn to screen when it is requested as part of a web page. The baseline image will draw one pixel line at a time, from top to bottom. The progressive image will show a fuzzy image to start with and then progressively improve as more information about the image comes down the line.

The original JPEG format is more than a decade old and despite its popularity it is beginning to show its age. So in 2000 the specification for a new version of JPEG was released. The revision, called JPEG2000, uses wavelet technology to produce smaller (by up to 20%), sharper files with less artifacts than traditional JPEG. The standard also includes options to use different compression settings and color depths on selections within images, as well as making it possible to save images in lossless form.

Photoshop enables you to save in the JPEG2000 format via the Save As command. The feature’s dialog contains a settings section (1), setting for the download preview (2) and a preview image (3). The format also supports layer transparency, saved selections, metadata, and 16-bit/ channel images.

The ‘Jump to’ or ‘Edit in’ buttons at the bottom of the Photoshop and ImageReady toolbars allow you to switch programs dragging with you the currently selected open document.

Using combinations of keyboard keys you can quickly access commands, features and menu options. Learn ones you use regularly to speed up your work. When shortcuts are available they’re listed in this book in the Entry heading with both Mac and Windows equivalents. The default shortcut for specific menu options are displayed on the right of the menu list (1).

From version CS Photoshop provided the ability to let you assign your own favorite shortcuts to regularly used features or actions.

The shortcut keys associated with each menu and key options can be customized via the Keyboard Shortcuts dialog.

Here you can change the default stroke combinations (1), add your own or completely replace all the assigned shortcuts with a custom set designed around the way you work.

The completed set of shortcut keystrokes can then be output as a convenient HTML file by pressing the Summarize button at the bottom of the dialog.

Keywords are single word descriptions of the content of image files. Most photo libraries use keywords as part of the way they locate images with specific content.

The words are stored in the metadata associated with the picture. Users can allocate, edit and create new keywords (and keyword categories) using the File Info palette in Photoshop and Keywords panel in the Bridge browser.

To locate pictures with specific keywords input the text into the Find feature in Bridge setting Keywords as the location for the search.

The Keyword panel displays the keyword options that are available for assigning to pictures in Bridge. New keywords and keyword categories (set) can be added to the panel by clicking the New Keyword Set (1) and New Keyword (2) buttons at the bottom of the panel. Unwanted sets or keywords can be removed by selecting first and then clicking the Deleted button (3). Unknown keywords imported with newly downloaded or edited pictures are stored in the panel under the Other Keywords set.

Knockout is a mode from the Blending Options palette (1) located in the Layer Style menu that allows you to be more creative with the ways layers interact with other layers.

It can be used with text and vector shapes to great effect. To illustrate how the feature works I’ve created a blue star layer on top that will be used as the Knockout layer. It’s above four jigsaw piece layers and all five are grouped (placed in a layer set). The background is a photo of bananas and there’s a yellow layer above that.

If the star is set to Shallow Knockout with opacity at 0% it would cut through the layer underneath and reveal the next layer. As the jigsaw pieces are in a group (set) it cuts through them too and reveals the yellow layer below. If the star is set to Deep Knockout with opacity at 0% it cuts through all the layers and reveals the background layer.