Changing color modes
Changing an image to another color mode, such as RGB, CMYK, or grayscale, changes the image’s color structure and size and can affect how the image displays and prints.
In this section, you’ll learn about
• changing the color mode of images
• changing images to the paletted color mode
Changing the color mode of images
In Corel PHOTO-PAINT, the colors of images are defined by color modes. Computer monitors display images in the RGB color mode; images in Corel PHOTO-PAINT are created in the RGB color mode by default.
Color modes are described by their component colors and bit depth. For example, the RGB (24-bit) color mode is composed of red, green, and blue channels and has a bit depth of 24 bits. Similarly, the CMYK (32-bit) color mode is composed of cyan, magenta, yellow, and black channels and has a bit depth of 32 bits. Each channel has a bit depth of 8 bits.
Although on the screen you may not be able to see the difference between an image in the CMYK color mode and an image in the RGB color mode, the images are quite different. Colors from the RGB color space can cover a greater range of the visual spectrum (they have a larger gamut) than those from the CMYK color space. For the same image dimensions, a CMYK image has a larger file size than an RGB image, but it contains the channels necessary to print standard inks.
Each time you convert an image, you may lose color information. For this reason, you should finish editing and then save an image before you convert it to a new color mode.
Corel PHOTO-PAINT supports the following color modes:
• Black-and-white (1-bit) • Grayscale (8-bit)
• Duotone (8-bit) • Paletted (8-bit)
• RGB color (24-bit) • Lab color (24-bit)
• CMYK color (32-bit)• Multichannel
• Grayscale (16-bit) • RGB color (48-bit)
• NTSC RGB (video)• PAL RGB (video)
To change the color mode of an image
• Click Image, and click one of the following:
• Convert to grayscale (8-bit)
• Convert to RGB color (24-bit)
• Convert to CMYK color (32-bit)
• Convert to ` Lab color (24-bit)
• Convert to ` Multichannel
• Convert to ` Grayscale (16-bit)
• Convert to ` RGB color (48-bit)
• Convert to ` NTSC RGB
• Convert to ` PAL RGB
Changing images to the paletted color mode
The paletted color mode, also called indexed color mode, is frequently used for GIF images on the Web. When you convert a complex image to the paletted color mode, a fixed color value is assigned to each pixel. These values are stored in a compact color table, or palette. As a result, the paletted image contains less data than the original, and it has a smaller file size. Paletted color mode is an 8-bit mode that stores and displays images using up to 256 colors.
Choosing, editing, and saving a color palette
When you change an image to the paletted color mode, you use a predefined or a custom color palette and then edit the palette by replacing individual colors. If you choose the Optimized color palette, you can also edit the palette by specifying a range sensitivity color.
The color palette you use to convert the image is called the processed color palette, and it can be saved for use with other images.