Bitmap Properties

(see also: Understanding Vectors and Bitmaps)

Bitmap Color Mode

The color mode of a Bitmap exists much the same way as colors inside of a vector object; unlike a vector object, however, a bitmap contains dozens of colors. This color mode will set the mode for the entire bitmap. A bitmap can't be more than one color mode at a time. This is useful for color output during printing when trying to hit certain colors.

To change the Color Mode:

• Select the bitmap.
• From the Bitmap menu, point to Color Mode and select the desired color mode.
  
  
  • Grayscale changes the colors to shades of gray from white to black.
  •  Black and White changes the color to strictly black and white pixels. No gray colors are used here.
  • RGB changes it to the RGB Color mode using Red, Green, and Blue. This is best for monitors and screens.
  •  Indexed Color is an antiquated version of CMYK (8-bit color compared to CMYK's 32-bit color) that produces low quality images but takes up less memory.
  •  CMYK changes it to the CMYK color mode, used in printing. Note, however, that most RIP software is designed to accurately translate RGB to CMYK in the RIP process, so this mode is not always required.

The newly selected color mode appears in the upper-right corner of the Bitmap tab in DesignCentral.

Changing Bitmap Resolution

The DesignCentral - Bitmap tab allows you to change the resolution of a bitmap.

• Select the bitmap.
• Select the Bitmap tab in DesignCentral.
  
• Select the new resolution from the PPI fields at the bottom of the tab.
  • Alternatively, you can use the Rasterize option  in the Bitmap menu to change the resolution

Ensure that Proportional is checked to keep the horizontal and vertical resolutions the same.

Changing the resolution does not change the number of pixels in the bitmap; it merely changes how many pixels fit into an inch. As the resolution of a bitmap is increased, the area covered by the bitmap will decrease, because more pixels will fit into each square inch. Decreasing the resolution will cause the bitmap to cover a larger area. You can reduce the quality of a bitmap by reducing the resolution, but you cannot improve the quality by increasing it.

Resampling a Bitmap

Resampling changes the resolution of an image without changing the area it covers. It does this by increasing or decreasing the number of pixels used to represent the image. At the same time, the software changes the resolution to compensate for the change in pixel count, so that the bitmap remains the same size.

Resampling an image will degrade it to some extent. Resampling to a lower resolution makes the image blocky and jagged. Resampling to a higher resolution may blur the image. If you resample an image and don't like the results, use Undo to return it to its previous state. Do not resample it again.

• Select the bitmap.
• From the Bitmap menu, select Resample.
  
  • The Adjust Bitmap Size dialog box appears.
    
    
• Adjust the values in Resample dialog box.