In Canvas X Draw, image modes define the color model and number of colors that can be used in images. When you create a new paint object in Canvas X Draw, you select an image mode: Black & White, Grayscale, RGB Color, CMYK Color, or LAB Color. When you select a paint object, Canvas X Draw displays the image mode in the Properties bar.
The image mode also appears in the Status bar if Object Details has been selected to appear in an information field.
Filters produce different results depending on the image mode. When you paint, the opacity setting of a brush acts differently on images in different modes. For the most predictable results with filters and paint tools, use RGB color mode.
Posterizing a LAB image introduces color to light areas.
RGB image posterized 4 levels
LAB image posterized 4 levels
When you import an image from another source either by opening, placing, or pasting an image file, Canvas X Draw assigns an image mode based on the number of colors and the color model used in the image.
The following table shows the image modes that Canvas X Draw assigns when you import images in some common image formats.
Assigned image mode
RGB Color, CMYK Color, or Grayscale
256-color image: Indexed
Black & White
Same as original image mode
You might want to change modes so you can use certain features, or reduce memory requirements; e.g., you might want to convert an Indexed image to RGB to apply image filters. You might want to convert an RGB image to Grayscale mode to save memory when a document is printed without color.
You can access the Image Mode menu on the Properties bar or by choosing Image | Mode.
Some modes are available only if the object’s current mode is compatible; e.g., Black & White mode and Duotone mode are available only when Grayscale paint objects are selected.
If the mode you choose does not support an image’s full color range, a message asks you to confirm the change. Click OK to proceed.
If you choose Duotone mode or Indexed mode, select options in a dialog box and then click OK to complete the conversion. (See Duotone Image Mode and Indexed Image Mode.)
Black & White image mode is used for scanned line art and black-and-white (“bitmap”) images, which contain only black and white pixels. Images in Black & White mode require the least amount of memory and disk space.
Grayscale mode images and Multichannel mode images are the only images you can directly convert to Black & White mode. If an image is not Grayscale, convert it to Grayscale mode first if you want to convert it to Black & White mode.
When you paste a selection into a Black & White image, Canvas X Draw uses diffusion dither on the selection.
Grayscale mode is appropriate for images scanned from black & white photographs or when the image will never be printed in color. In Grayscale mode, pixels use 256 brightness levels to represent a range of shades from pure black to pure white. Grayscale uses 8 bits per pixel and requires less memory than most color modes.
If you convert a color image to Grayscale mode, Canvas X Draw discards all color information.
Indexed color mode uses a palette of 256 colors for images. Since this mode stores fewer colors, it requires significantly less memory than RGB and CMYK color modes, both of which support millions of colors. Smaller memory requirements make Indexed mode especially useful for images used on Web pages.
An Indexed image includes a color table, or palette, of colors used in the image. When you convert an existing image to Indexed mode, you can specify the number of colors from the image to include in the color table.
Most image filters, effects, and opacity controls aren’t available to be applied to Indexed images, except the Offset and De-Interlace filters.
In the Indexed Color dialog box, choose an option in the Indexed Color dialog box for the color table.
Depending on which method you select, the Colors area in the dialog box displays information about how the color table is computed.
Creates a color table from the colors in the image, if the image contains 256 colors or less; otherwise, this option isn’t available. The Colors area displays the number of colors in the selected image.
Creates a color table based on the operating system’s palette of 256 colors (System), or a subset of these colors (Uniform). The Colors area displays the number of colors in the operating system’s palette; if you choose Uniform, a pop-up menu that lets you select 8, 27, 64, 125, 216, or 256 colors appears.
Creates a color table from the most frequently used colors in the image. The Colors area displays a text box that lets you enter a number of colors from 2 to 256
Lets you create a color table, load, and save color table files. The Colors area displays “Custom colors”.
Applies the last color table used in the Indexed Color dialog box during the current Canvas X Draw session. The Colors area displays the number of colors in the last color table created by the Indexed Color dialog box during the current Canvas X Draw session.
Changes colors to their closest equivalent in the selected color table without dithering.
Approximates colors not in the palette by arranging palette color in geometric patterns (available for Uniform/System method only).
Approximates non-palette colors by randomly dithering available colors; creates the most natural effect.
If you select the Custom option, the Color Table dialog box appears.
If the image is already Indexed, choose Image | Mode | Color Table to open the Color Table dialog box.
You can edit individual colors in the palette, create a blend of colors, and select from several preset color palettes, including System and Grayscale palettes. In addition, palettes can be saved or loaded.
In the Color Table dialog box, a grid of 256 color swatches appears; each swatch represents one color in the palette. By default, the Custom option appears in the Table menu, and the color swatches show the last palette used in the dialog box.
The Table menu lets you choose among preset color tables:
A range of sunset-like colors.
A ramp from pure black to pure white.
The palette of colors supported by Macintosh.
A set of rainbow colors.
A set of 216 colors that can be displayed without dithering by nearly all Web browsers. This option is also referred to as a “browser safe” palette.
The palette of colors supported by Windows.
You can also create a custom color table.
By using the Load and Save options in the Color Table dialog box, you can save color tables to your hard disk or load a saved color table file into the Color Table dialog box.
Specify a location on your hard disk to save the color table, and then click Save. Canvas X Draw saves the color table.
Save your custom color tables in a central location on the corporate network and share them with co-workers.
After choosing a color table, you can customize individual colors in it using a color picker dialog box.
Canvas X Draw lets you create blends of selected swatches in the color table. When you do this, the first and last swatches you select don’t affect the final blend in the color table. How the blend appears in the color table is determined by the two colors you choose in the Color Picker in step 2 of this procedure.
RGB color mode is used most often when working with high-quality full-color images, such as those from color scanners and digitized photographs stored on CD-ROM.
RGB color mode is the most reliable mode to use for images you want to modify with painting tools and filters. However, the full range of RGB colors exceeds the range that commercial printing can reproduce, so you should be aware of the limitations of the printing method that will be used. Also, an RGB color image is device dependent, which means that the same RGB values can look different when displayed on different monitors.
In RGB color mode, each pixel has a red, green, and blue component. Each component, referred to as a color channel, has 256 intensity levels. The combination of the intensity value in each channel creates each pixel’s color.
Remember that RGB is used for images on the Web and CMYK is used for print.
CMYK color mode is based on the four color inks used in commercial printing (and by some desktop printers): cyan, magenta, yellow, and black. Some color scanners can produce CMYK images.
In a CMYK color image, each pixel has a cyan, magenta, yellow, and black component. Each of these color channels has 256 intensity levels. The combination of the intensity value in each channel creates each pixel’s color. Because monitors are RGB devices, they can’t display CMYK colors directly. However, Canvas X Draw attempts to display CMYK images as they will appear when printed.
The Commission Internationale d’Eclairage (CIE) developed the LAB color mode as an international color standard to overcome the device dependency of the RGB and CMYK modes. In a LAB color mode image in Canvas X Draw, each pixel has one lightness and two color components. The Lightness (L) channel has 256 levels of intensity. The two color channels, labeled A and B, provide a color range from red to green and yellow to blue, respectively.
Some companies sell collections of images in LAB color mode. Editing LAB color mode images with some filters or painting tools can have interesting and unpredictable effects.
In traditional graphics arts reproduction, a “duotone” is a grayscale image printed with black and an additional color. Canvas X Draw lets you create duotone images, as well as “monotone,” “tritone,” and “quadtone” images (printed with one, three, or four colors, respectively).
The term “Duotone” refers to the Duotone image mode, not just to images printed with two inks. In Duotone mode, an image can be printed as a monotone, duotone, tritone, or quadtone.
Printing images as duotones can add interest and increase the tonal range reproduced from grayscale photographs, without the additional expense of printing full-color images. The duotone effect can be subtle or striking, depending on the color used and the amount added to the image. In any case, the additional colors are used to reproduce the gray values in the image, rather than to reproduce specific colors.
To create a monotone, duotone, tritone, or quadtone in Canvas X Draw, you must convert a Grayscale image to Duotone mode. Unlike other image modes, once an image is converted to Duotone mode, you cannot work with individual image channels. Instead, you can adjust curves for each color “channel” in the Duotone Options dialog box.
You can also select image modes by choosing Image | Mode.
If you plan to export a duotone image to another graphics or page layout program, be sure the color names exactly match the color names in the other application. Otherwise, you might produce more color separations than necessary.
You can select and change the following ink settings for images in Duotone mode.
Choose Monotone, Duotone, Tritone, or Quadtone.
Click the palette icons and select colors in the palettes for each ink. Type process and spot color names in the text boxes.
Click to adjust the screen display of the Duotone inks. Because the appearance of spot-color combinations can’t be predicted within Canvas X Draw, you can do this if you have an accurate printed reference for the colors you select. Overprint Colors settings do not affect color separations, but will change the appearance of color composites printed on desktop color printers. In the Overprint Colors dialog box, click the color squares to open a color selector dialog box. Choose the color you want to represent the ink combination on screen and then click OK.
After you convert an image to Duotone mode, reopen the Duotone Options dialog box to adjust the color curves, change ink colors, as well as use the Load and Save options.
Use the Load and Save buttons in the Duotone Options dialog box to work with files of duotone options information. Canvas X Draw uses a file format compatible with the duotone options files used by the Photoshop image-editing program, so you can load files saved from Photoshop, and files saved by Canvas X Draw can be loaded into Photoshop.
Multichannel image mode lets you work with multiple channels of grayscale information for a grayscale image. In multichannel mode, each channel contains lightness values as in other image modes, but the values do not relate to color components.
When you convert an image to Multichannel mode, the image data does not change; e.g., if you convert an RGB Color mode image to Multichannel mode, the Red, Green, and Blue channels retain the same pixel information, but the channels no longer represent color pixels. The channels in Multichannel mode are labeled numerically (#1, #2, and so on) in the Channels palette.
The Multichannel mode is not available if you select a paint object containing an image in Black & White image mode.