To edit digital images, you must rely heavily on computer software. The software allows you to manipulate the image. You can crop, retouch, and change colors of the entire image or any section of the image. With the powerful software packages available, you can change the original image into something completely different by merging one digital image with another. The scope of the aesthetic and creative aspects of the final digital image is limitless.

Editing digital images involves using graphic-interface software. This type of software is much easier to learn than text-based software. There are two essential elements of graphic-interface software: MOUSE and a BIT-MAPPED DISPLAY. The mouse is a small hand-held device that must be connected by a cable to a computer. When you manipulate the mouse on a desktop, it causes the cursor to move on the screen of the computer monitor. This method allows you to move files, run programs, draw lines, and execute commands. You can accomplish this by moving the mouse to the appropriate location and "clicking" a button. A bit-mapped display is composed

of tiny dots that am turned on or off individually; this allows the computer to show graphic images in addition to text. Bit-mapped displays are used in Apple application software and Microsoft "Windows" programs.

Graphical interfaces are easy to use because they provide a "point and click" approach to operating software. Files and software functions are displayed as small graphical icon fig. 3-12. For example, an icon bearing the image of a folder may represent a file; or an icon bearing the image of a magnifying glass may allow you to zoom in on a portion of the screen. Graphical interfaces also use WINDOWS. A window can be compared to an open drawer (folder) of a file cabinet (hard drive). Windows are displayed as frames on the screen. These display different "files" in the "folder."

Two software packages used in Navy imaging facilities for electronic imaging are Adobe Photoshop and Aldus PhotoStyler. These software packages are not just photographic editing and enhancement tools but complete illustration programs. These two programs operate in the same manner. With "hands on" experience, you will soon become proficient.

Photoshop is available for both Macintosh and PC/windows platforms. PhotoStyler is designed in the PC windows environment only. Figure 3-13 shows some of the tools available in these two computer programs. As you can see, these two imaging software packages are very similar.

Although there are several software packages available for editing electronic images, they are all similar. These similarities are as follows: paint tools, selection tools, filters, and color correction.

PAINT TOOLS

Paint tools allow you to retouch or add selected colors to an image. The tools typically include a paintbrush that allows you to draw in a color or pattern, a paint bucket that allows you to pour a color or pattern into a selected section of an image, and a spray paint tool that provides you with an airbrush effect. These image-editing programs allow you to perform color correction and to change contrast and density of the image. Other common tools may include a pencil for adding or deleting pixels, a teardrop for softening edges, and a finger paint or smudging tool for smudging colors.

An interesting option in most image-editing programs is the cloning tool. To use the cloning tool, you first select the icon; then you must click the mouse

Figure 3-12.-Open file displayed on PhotoStyler palette.

button after moving the cursor to the portion of an image that you want to replicate. Now move the cursor to the part of the image where you want to "paint" the image that you selected fig 3-14 . This cloning tool is particularly useful for removing dust spots, scratches, reflections, and so forth.

The imageediting software used by Navy imaging commands allows you to modify the way these tools function. You can change the size and shape of the brushes, soften the edges of the tools, and control the transparency of selected colors.