Color Reproduction

PageStream can print documents in color on color printers, and can separate color documents for printing on commercial printing presses. Separating a document means that a printing plate for each ink is created. The printed page is created by printing each ink on the paper with its printing plate.

Spot color and process color printing are the two methods of printing colors on a printing press. Spot colors are printed with premixed or custom mixed inks. They are normally used only for a small number of colors, because each color requires a separate printing plate and increases the expense.

Process colors are printed using four inks: cyan, magenta, yellow and black. Other colors are simulated by printing dots of different colors close together. The human eye perceives these combinations of dots as one color.

PageStream allows you to specify spot and process colors. You can combine them in one document if you wish. Spot colors are often used in process color documents for special colors that you want to reproduce exactly. For example, if you use a spot color in a document with process colors, you will create five plates for each pagecyan, magenta, yellow, black, and the spot color.

Spot vs Process colors

If you are printing directly to a color printer to create your final copy, you can use either spot or process colors; the distinction is only important if you are creating color separations for printing on a commercial press.

Spot colors should be used when you need three or less colors. Spot colors are generally cheaper than process colors unless you have too many of them. You can also use spot colors when you need to exactly reproduce a color. For example, a client may specify certain specific colors for their logo that must be precisely matched. Spot colors are necessary when you need to print metallic, fluorescent or other special inks.

Process colors should be used when you're using more than four colors in a layout and when you want to reproduce color photographs in color. You may want to use process and spot colors together when you need to match a color precisely or use a special ink in a process color job.

Knocking Out and Overprinting colors

When objects of different colors overlap, PageStream normally does not print the portion of the bottom object which is overlapped by the top object. This is referred to as a knockout because the top color knocks out the bottom color.

If the bottom color is not knocked out, the top ink will overprint the bottom ink, creating a third color. This is referred to as an overprint and is generally only used when you want to avoid trapping problems, and when the top color is black or a similar dark color that is printed over a light color. For example, if the top object is black text and the bottom object is a bitmapped picture, it is likely that unsightly white gaps would appear around the letters due to plate shifting, so it would be better to overprint the black text over the background colors.

Creating and Editing colors

To apply a color: Choose Line & Fill from the Type or Object menu, as appropriate. Click on the Line tab and select the line color from the Color pop-up menu. Click on the Fill tab and select the fill color from the Color pop-up menu. If you set the Type to Gradient, Radial or Shape, you will also have to select the color to blend to from the To pop-up menu.

To apply a lighter version of a color: Follow the above steps above, but change the percentage in the text box to the right of the Color pop-up menu to a value between 0 and 100%. 100% is the solid color and lesser values are lightened tints.

PageStream allows you to create new named and custom colors. Named colors are added to the Color pop-up menus and to the Color palette so that you can use them again for other objects or text. Changing the color components of a named color changes all objects or text using that color. Custom colors are useful when you want to create a color for one instance and do not want it added to the pop-up menus and palette. Changing the color components of a custom color changes only the selected objects or text.

Custom colors are also created by the Blend feature in drawing programs such as Art Expression for intermediate objects.

To do Do this
Create or edit a named color Choose Define Colors from the Edit menu, or choose any color from the appropriate Color pop-up menu and click the Browse (>>) button to its right. The Define Colors dialog box will open. Click on Edit to edit the selected color. Click on New to create a new named color. If you click on New while a color name is selected, the default values will match that color.
Create or edit a custom color Choose Custom from the appropriate Color pop-up menu. Click the Browse (>>) button to its right. The Edit Color dialog box will open. Set the color values and click OK.

Defining colors

The Define Colors dialog box opens whenever you click the browse button next to a Color pop-up menu with a named color selected, or when you click on a named color in the Color palette while holding down an Shift key. This dialog box allows you to create new colors, edit any existing color, delete colors, append colors to the list, and save the color list to an external color file.

To edit an existing color: Select the color from the scrolling list and click Edit to display the Edit Color dialog box. Change the values and click OK.

To create a new color: Select the existing color closest in color to the new color and click the New button. This will open the Edit Color dialog box with the existing color's values set, but will not alter the existing color. Set the color values and give the color a name. Click OK to add the color to the list of colors.

Editing colors

The Edit Color dialog box allows you to change the color values for a color.

To edit a color:

1. Set the color name for named colors.

Enter the color name into the Name button. If editing a custom color this field will be uneditable.

2. Choose a color model from the Model pop-up menu.

Choose the color model which suits your needs best.

To choose a PANTONE color, use a PANTONE Process Color Imaging Guide 1000.

3. Choose the type of color.

Click on Type to toggle between spot and process colors. For a process color, the color model and color values determine how the color will print. For a spot color, the color model and color values determine how the color will be displayed on screen, or printed if forced to a process plate.

4. Choose the print method.

Click on Print to toggle between Knockout and Overprint. Choose Overprint to make the objects to which this color is applied print on top of objects of other colors that are behind it. Choose Knockout to make objects of other colors that are behind it not print.

5. Set the tint value.

Enter a percentage between 0 and 100%; the smaller the value, the lighter the tint. This is designed to help you create consistant variations on a PANTONE color. You should name tints to reflect the base spot color. For example, a 30% tint of BrightRed could be named BrightRed30.

6. Set the color values.

Enter values into the text boxs for each color component, or adjust the scroll bars. For PANTONE or other library colors, choose a color from the list.

7. Click OK.

If you created or edited a named color, you will return to the Define Colors dialog box. Continue to create and edit colors if you want before clicking on OK in this dialog box.

Color models

Grays: This is a simple color system for grayscales. Colors are defined as a percentage of black.

CMYK: This is the primary model used for printing and uses cyan, magenta, yellow and black intensities to create colors. It is a subtractive system100% of cyan, magenta and yellow create black, 0% creates white, equal percentages create gray, and varying percentages create different colors. Black is added to the three primary colors to produce contrast.

RGB: This is the primary model for video and uses red, green and blue intensities to create colors. It is an additive system100% of each color creates white, 0% creates black, equal percentages create gray, and varying percentages create different colors.

HSV: This model uses a color wheel to define colors and measures hue, saturation and value. Hue is the actual color and is specified in degrees because it is a point on the color wheel. Saturation is the amount of color relative to white, or the relative purity of the hue, and is expressed as a percentage. Bright colors are highly saturated while dull colors have low saturation. Value is the relative lightness or darkness of a hue. A color with a value of 0% is pure black.

HLS: This mode is similar to HSV but measures hue, lightness and saturation. Lightness is another way of measuring value.

Specifying a PANTONE color

It can be difficult to choose colors for printing that will print accurately on a printing press. There are many factors which affect color accuracy, including the press quality and the light in which you view the paper.

The PANTONE MATCHING SYSTEM was developed by Pantone, Inc., to standardize how spot colors are specified by commercial printers, ink makers and desktop publishing users. The PANTONE colors are standardized so you can be assured that the colors you choose will be printed accurately. Use the PANTONE Color Formula Guide 1000 for accurate PANTONE"-identified solid color standards for coated and uncoated paper stock. Choose PANTONE Coated from the Model pop-up menu in the Edit Color dialog box to choose PANTONE MATCHING SYSTEM colors for coated paper, and PANTONE Uncoated for uncoated paper.

PANTONE Color Computer hard copy simulations used in this product are four-color process simulations and may not match PANTONE"-identified solid color standards. Use PANTONE Color Reference Manuals for accurate color. PANTONE Color simulations are obtainable only on licensed hardware that is driven by qualified, Pantone-licensed software packages. Contact Pantone, Inc., for a current list of qualified licensees. Pantone, Inc., assumes no responsibility for color inaccuracies on non-licensed output devices. Pantone, Inc., 1986, 1997.

Pantone, Inc.
590 Commerce Boulevard
Carlstadt, NJ 07072-3098
tel: 201.935.5500
fax: 201.896.0242

If you wish to use these PANTONE colors for process color separations, the PANTONE ProSim (Process Simulated) color model allows you to simulate many PANTONE spot colors using four color process separations.

The PANTONE Process Color System is designed to reproduce colors using PANTONE process inks. The more than 3000 colors are organized chromatically. Use the PANTONE Process Color System Guide for accurate PANTONE"-identified color standards for coated paper stock.

For best results, you should work in 24 bit mode (millions of colors). With AmigaOS computers, this requires CyberGraphX and a graphic card. With most MacOS computers, this requires additional video memory. Always use a PANTONE Color Reference Manual to choose colors.

When you choose a PANTONE color for a named color, the PANTONE name will be inserted into the Name text box. The Type button will change to Spot or Process as applicable. It is recommended that you use the actual PANTONE name for spot colors unless you edit the color components by switching to another color model.