Use the Spot Tint Library dialog box to define the default settings for a spot tint library and its colors.
Spot Solid Library
User library
Enables you to select the user library for which you want to define spot tint settings. You can create more user libraries in the Color Database Editor. The user libraries contain recipes for the solid (100%) spot colors.
Factory library
Enables you to select a factory library for which you want to define spot tint settings. The factory libraries contain recipes for the solid (100%) spot colors.
Press substrate white point
Defines the color of the substrate on which the target device, for example, a press, will print spot colors. You can use the default settings, or you can use a spectrophotometer to measure the substrate white point and type its L*a*b* definition. The software only uses the white point value when you click the Customize button, select the Target Spot Tint Color check box, and type L*a*b* values to customize selected tints for a spot color. The software uses the white point value to ensure that you enter tint values that the proofer can reproduce. The software does not use the white point when you select the spot tint color library in a hot folder or virtual printer.
Proofer profile
Enables you to select the proofer profile for the media on which the proofer will print spot colors. Available only when you select a color library in CMYK color space. The software uses the proofer profile when you click the Customize button, select the Target Spot Tint Color check box, and type L*a*b* values to customize selected tints for a spot color. The software uses the proofer profile to derive L*a*b* values, and it uses the data to ensure that you enter tint values that the proofer can reproduce.
When you select the spot tint color library in a hot folder or virtual printer, the software recommends that the proofer profile selected in the hot folder or virtual printer be the same as the proofer profile associated with the selected spot tint library. However, it is not required. The software uses the proofer profile to calculate the white point when the hot folder or virtual printer uses absolute rendering intent, and the same proofer profile ensures that the same white point is used for process colors and spot tints.
Library defaults
Simulate
Enables you to simulate the dot gain for the 50% tint or the minimum highlight dot techniques used in flexographic printing. Select one of the following options:
No Highlight Adjustment—turns off simulation of the flexographic minimum highlight dot, but lets you simulate the spot tint colors on press.
Highlight Bump—simulates the flexographic technique that moves the fine highlight dots into the tone range that can be imaged on a flexographic plate. This technique is sometimes called a bump curve. For example, when 5% is the smallest highlight tint that can be imaged on a flexographic plate, all tints in the input file from 0.1% to 4.9% are moved into the tone range between 5% and 100%. In other words, the Highlight Bump option raises the input values from the identified minimum dot. As a result, printed images appear darker.
Highlight Minimum Dot—simulates the flexographic technique that removes the fine highlight dots from a flexographic plate and images them at 0% or paper tint. In other words, the Highlight Minimum Dot option clips the input values below the identified minimum dot. As a result, printed images appear to lack detail in highlight areas.
Minimum Dot on Plate
Specifies a percentage from 0.1 to 10 that identifies the smallest highlight tint that can be imaged on a flexographic plate.
In the Simulate list, when you select Highlight Bump, all tint percentages in the input file that are below the Minimum Dot on Plate value will be moved above the value. As a result, the tint range is compressed (for example, from 5% to 100%) and images appear darker. The Minimum Dot on Plate value must be equal to or less than the Minimum Dot on Press value.
In the Simulate list, when you select Highlight Minimum Dot, all tint percentages in the input file that are below the Minimum Dot on Plate value will be imaged at 0% or paper tint. As a result, the highlight areas lack detail.
Minimum Dot Printed on Press
Note: The Minimum Dot Printed on Press box is optional. It is not required for Kodak Proofing Software to enhance spot color tints, but it can provide additional information for the software to use.
Specifies a percentage from 0.1 to 30 that identifies the dot gain on press for the minimum dot that can be imaged on a flexographic plate. In other words, the Minimum Dot Printed on Press value identifies the dot gain for the Minimum Dot on Plate value. For example, when the minimum dot on a flexographic plate is 3% and the dot prints on press at 15%, you would type 15% in the Minimum Dot Printed on Press box.
The Minimum Dot on Plate value must be equal to or less than the Minimum Dot on Press value.
Contrast Index
Determines where to place the contrast reduction in the tone scale for the bump curve to simulate how the flexographic press prints. In other words, the Contrast Index value determines whether you see the contrast reduction in the highlights, midtones, or shadows.
The Contrast Index option becomes available when you select Highlight Bump in the Simulate list. The Highlight Bump option simulates a bump curve used in flexographic printing. A bump curve shortens the tone scale and consequently reduces contrast.
In the Contrast Index box, type a number that is greater than or equal to the Minimum Dot Printed on Plate value and less than or equal to 200. One digit after the decimal point is allowed. The Contrast Index value must be equal to or greater than the Minimum Dot Printed on Plate value. For example, when the Minimum Dot Printed on Plate value is 9, the Contrast Index value must be 9 or greater.
From 0.1 to 100, the Contrast Index value indicates where the contrast reduction ends and the original tone scale for the input file is preserved. For example, a Contrast Index value of 60 indicates that the contrast reduction is spread over the highlights and midtones up to a 60% tint in the input file.
From 100 to 200, the contrast reduction is spread over the entire range of the input tints. The following examples illustrate several Contrast Index values for the case where the minimum dot printed on plate is 9%.
Example 1—Contrast Index value is 150 (the default setting)
A setting of 150 spreads the contrast reduction evenly across all tints in the input file. As a result, you see some contrast reduction in the highlights, midtones, and shadows. The x axis is the tint on plate, and the y axis is the tint in the input file.
Example 2—Contrast Index value is set to its minimum setting and is equal to the Minimum Dot Printed on Plate value
For example, when the Minimum Dot on Plate value is 9, the Contrast Index value is 9 too.
The minimum setting squeezes the contrast reduction into a single point—the minimum dot on plate. As a result, the highlight areas (below 9% in this example) lack detail, but the midtones and shadows are unaffected. The x axis is the tint on plate, and the y axis is the tint in the input file.
Example 3—Contrast Index value is 60
A setting of 60 spreads the contrast reduction over the highlights and midtones up to 60%. As a result, you see less contrast in the highlight and midtone areas, but shadow contrast is unaffected. The x axis is the tint on plate, and the y axis is the tint in the input file.
Example 4—Contrast Index value is 200
A setting of 200 shifts the contrast reduction to the shadow areas. As a result, the highlight areas retain their contrast, but the upper midtones and shadow areas lose contrast. The x axis is the tint on plate, and the y axis is the tint in the input file.
Dot Gain at 50%
Specifies a percentage from 0 to 40 that indicates the measured dot gain on press. Decimals are not allowed. Zero indicates no dot gain (also called linear). For example, when a 50% dot in the input file measures 68% on press, you would type 18% in the Dot Gain at 50% box (68 - 50 = 18).
Buttons
Summary
Displays a summary of the settings for the color library and any spot colors that you customized for the library
Customize
Enables you to customize tints for individual spot colors in the selected color library. The software uses the customized tint settings for the identified spot colors and the default library tint settings for all other spot colors.
Save As
Saves changes to a different spot tint library or to a new spot tint library
| Parent topic: Spot tint libraries |