PowerPoint.Advanced.Presentation.Techniques [Electronic resources] نسخه متنی

Using Special Image Modes

Most images can be displayed in any of four modes:

Automatic: This is usually color if it is a color image. It's the image default appearance and is best for color presentations.

Grayscale: This is a gray-shaded version of the original image, with shades of gray substituted for each color. Rather than separate values for red, green, and blue, each pixel is a numeric shade of gray from 0 (black) to 255 (white). This works well for presentations that you'll give in one color, such as with transparencies printed on a black-and-white printer.

Black and white: The entire image consists of black and white. There is no shading; it's 1-bit color depth. Any colors are rounded to either black or white, whichever they are closest to. This results in a loss of image quality in an image that had any shading. It simulates what the picture will look like when faxed.

Washout: This is a light background image of the original, like a watermark, suitable for placement behind text. Its effect can be subtle.

Figure 8-13 shows an image in each of the four modes. (You can't tell much difference between Automatic and Grayscale since this book is not in color, but you could immediately see the difference on your own screen.) To switch between the image modes, click the Color button on the Picture toolbar and choose from the menu that appears (see Figure 8-13).

Figure 8-13: The same image in four different image modes.

You can also change the image mode from the Picture tab of the Format Picture dialog box (refer to Figure 8-12). Choose an image mode from the Color drop-down list there.