High-quality color conversion assumes that the source color space of the objects to be converted is known or can be read out. If no matching document color space (output intent) is assigned to the objects in the PDF file, conversion is performed on the basis of the Document Color Space selected as the source profile and may produce results that differ from those anticipated by the document creator.
In most cases the PDF file converted using an Auto Setup queue is a device color space file optimized purely for the output without embedded profiles in individual objects. The output could be CMYK, RGB, Gray, or Multicolor depending on the target profile.
Data containing additional spot colors is not changed in the standard queue. All of the color information needed for PDF/X, including use of the target profile as the output intent, is set automatically in Auto Setup queues.
Auto Setup queues can be used as automatic functions for common tasks. However, if the workflow requires special configurations, changes can be made under Configurations / Define Configurations.
To learn more about managing hot folders that have been created using the Auto Setup Wizard or in the Define Queues main window, go to Queues
Choosing a DeviceLink or SmartLink conversion
Use Existing DeviceLink Profile
Use Existing DeviceLink Profile, to convert using an existing DeviceLink profile located in the standard profiles folder on your system. The DeviceLink profile selected in the Auto Setup Wizard configures the source profile of the file if files without embedded profiles are processed. The target profile is also set by Auto Setup since with the ColorLogic standard DeviceLink profiles, Auto Setup automatically enters all relevant PDF/X information. [link Read more about this in Configuration – PDF]
If a set-up mode with normalization was previously selected, the conversion is performed via the document color space to the target profile.
In the both the Save Inks and Optimize Total Area Coverage setup mode, the dropdown menu for choosing the DeviceLink profile will only show profiles whose source and target profile are identical.
Choosing Use SmartLink, DeviceLinks are calculated “on-the-fly” based on the ICC profiles used for the document color space and the target color space. Choose the rendering intent for calculation. Select the output intent of the PDF/X file under Prefer Output Intent if the document color space was not set manually.
High quality DeviceLink profiles are calculated which avoids issues associated with normal ICC conversion and ensures optimal color conversion.
“On-the-fly” conversion from document color space to target color space by choosing a source and target profile and a rendering intent (conversion methods).
Document Color Space
The document color space serves as a reference when it comes to creating a consistent printing color space for the colors of a PDF file. CMYK color spaces are mostly used as the document color spaces in the framework of print production since printing is generally done with CMYK inks. An RGB document color space may be encountered in modern publications for mobile media. Additional colors are used in HiFi packaging printing where the document color space can also be represented by a Multicolor profile if PDF/X-5n is used. ZePrA supports the full range of color spaces and the Multicolor license must be purchased to use the Multicolor space. If a PDF file contains individual RGB or CMYK objects with embedded profiles, these are color converted to the document color space. Data exchange should be based on the PDF/X standard for professional print production
Prefer Output Intent
In addition to the ICC device profiles in the individual objects in the PDF file, the entire PDF document may also be tagged with an output intent (an ICC device profile that describes the document color space). The document color space is unequivocally defined as the output intent in PDF/X documents. If this function is enabled, PDF/X files with different output intent can be correctly color converted in one queue because the respective output intent is taken into account instead of the document color space.
Note: This function is for PDF/X files only.
For conversion by means of ICC DeviceLink profiles, ZePrA offers five rendering methods when SmartLink is utilized, in addition to the four standard rendering intents.
Extended ZePrA Rendering Intents
The extended rendering intents included with ZePrA avoid incompatible color conversions which can result from the tables for the source and target profiles being calculated differently. To achieve accurate color conversions, ZePrA completely recalculates the source and target profile tables “on-the-fly” using the same algorithms found in ColorLogic’s profiling software CoPrA. These extended rendering intents are only available with the activated SmartLink function. If the Apply SmartLink checkbox is not enabled, or if SmartLink has not been licensed, only the four standard rendering intents are available.
Standard Compression: ColorLogic’s standard method, which is well suited for most applications. Neutral tones are converted using a relative colorimetric approach. If the paper white of the target profile is significantly more yellow than the source profile, the gray axis will look more yellow as well. If the target profile has a smaller color gamut than the source profile, the contrast range will be adapted to avoid a loss of image definition.
Black Point Compensation: Use Black Point Compensation to achieve the same results with a perceptive conversion as with “Relative Colorimetric with Black Point Compensation”. When converting from a large to a small color space, the image definition is preserved in the highlights and shadows, unlike with a pure Relative Colorimetric conversion. Neutral tones are converted using the ∫⁄intend. Out-of-gamut colors are cut off.
Dynamic Compression: Compares the source color space with the target color space and generates a compression that minimizes out-of-gamut areas. This setting preserves the brightness of the original color space while reducing the saturation, and therefore also preserves the image definition. As for the Standard Compression, the gray axis of the conversion is build relative to the paper white of the target profile.
Absolute Compression: This method is based on the absolute colorimetric intent but shows some differences. The contrast range in the highlights and shadows is adapted to avoid any loss of image definition. The rendering of neutral colors is based on absolute colorimetry without paper color simulation in the highlights. If the paper white of the used printing medium is significantly more yellow than the reference, the gray axis will look neutral despite the yellowish paper white.
Minimum Compression: This method is largely similar to the absolute colorimetric intent and only compensates close to the black and the white point. Maximum shadow contrast will be achieved and image definition will be preserved while the paper white will not be simulated. Use this rendering intent if you would like to achieve a very close reproduction, for example when using print standards like ISO Coated V2 or GRACoL2006 Coated1v2 on a digital printer.
Important: The rendering intent set under Images / Vectors is taken into account with PDF files and used when creating a DeviceLink profile “on-the-fly” with SmartLink. Select Ignore PDF Rendering Intents in the Options tab.
SmartLink Methods: Takes into account the various requirements of different printing conditions so that printed color is correctly matched and optimally separated for the required process.
Traditional Print – Classic – Conversions for offset, gravure, or newspaper printing. The DeviceLinks created ensure the black and gray, as well as primary, secondary and tertiary hues of the source profile are preserved. The total area coverage is taken from the target profile.
Traditional Print – Automatic. – The color and paper of the target color space differ significantly from the output intent or the document color space, choose the setting This option also ensures that the separation is preserved but the colors defined as exceptions are automatically calculated on the basis of both profiles used.
Large Format Print- Inkjet. – Printing on a large format ink system. The separation is structured with a strong GCR and late application of black. The black point and the total area coverage are automatically calculated in order to guarantee the best color output. All other conversion conform to the Traditional Print with Automatic method. If colors vary between different inkjet printers or between the inkjet printing systems and the source color space, (e.g ISOcoated V2 or GRACol) primary and secondary colors do not produce a satisfactory conversion. The Large Format Print- Inkjet method will automatically calculate the most appropriate exceptions.
Digital Print – Toner. – Digital production machines or office printers. This method uses the same DeviceLink presets for exceptions as the Large Format Print- Inkjet. The separation method ensures a high percentage of black is used to achieve a stable printout and a neutral gray balance. The total area coverage is taken from the target profile.
Creating Queues and Configurations
Specify a Queue Name to match the name of the configuration.
Specify the Base Folder in which the queue should be created. To create queues (hot folders) in the Base Folder, select Create Queue which will generate the required sub folder.
When a PDF file is sent to the Input folder of a created queue, ZePrA automatically converts it in accordance with the color management specifications and saves the converted file in the Output folder. The original file is moved to the Done folder. Files with issues are saved in the Error folder. The queues can be used immediately.
To create a new configuration only, disable the checkbox Create Queue
The wizard automatically handles the setup process and once complete, the new configuration and queue is available immediately.
Overview of File Conversion
Converting PDF files with Auto Setup Queues
The easiest way to set up a color management workflow is to use the Auto Setup in combination with the ColorLogic DeviceLink profile sets All sets are optimized so that the colors of both image and vector data in a PDF file can be reliably converted.
They are checked for smoothness and for visually correct conversion and have been proven in production.
All color information needed for the PDF/X, including use of the target profile as the output intent, normalizing and color conversion is set up in Auto Setup Wizard.
Gradients in vector graphics that consist of just one or two CMYK colors still contain only the original colors after application of the profile. The color values are adjusted in accordance with the purpose of optimization.
Example: If PDF objects are in the RGB color space and have the relative colorimetric rendering intent embedded, the Auto Setup queue automatically activates black point compensation to ensure clean reproduction of details in the shadows.
Grayscale: Grayscale objects might be converted in accordance with the presets for CMYK objects by preserving as much gray as possible and avoiding conversion to four colors. If the SmartLink function has been licensed, color conversions of objects with embedded profiles are always performed via SmartLink and use DeviceLink profiles to guarantee the best possible quality.
Spot Color: If the PDF files contain spot colors, the spot colors are not changed in the standard queues. To convert the spot colors to process colors, adjust the conversion later in the configuration.
No embedded profiles: By default no ICC device profiles are embedded in the individual objects of the output PDF file.
SmartLink: If the SmartLink function has been licensed, color conversions of objects with embedded profiles are always performed via SmartLink and using DeviceLink profiles in order to guarantee the best possible quality. PDF files can be optimized through the identical processing of image and vector data in Auto Setup queues.
PDF Transparencies: If a PDF file contains transparencies, the individual PDF objects are processed in exactly the same way as the PDF files without transparencies. The colors of the transparencies are converted as standard and the transparency information is preserved unchanged. Transparency reduction may be adjusted later on in the configuration under the PDF tab> (add link)Transparency Flattening .
Converting Pixel Based Files in Auto Setup Queues
Converting Pixel Based Files in Auto Setup Queues
TIFF, JPEG, PSD, or PSB image files in an Auto Setup queue are processed in ZePrA similar to the corresponding image objects in a PDF file. The settings under Images are relevant since there is no separate setup for pure image files.
For pure image data conversion of TIFF, JPEG, PSD and PSB images from a source color space to a target color space, it is advised to use the Auto Setup option Normalize and Convert Colors to New Output Condition and select one of two options:
Option 1: Use a previously created DeviceLink profile. The DeviceLink indicated in the Auto Setup Wizard is set to configure the source profile of the image if images without embedded profiles are processed. The target profile is also set by Auto Setup, however the conversion is performed via the document color space to the target profile to provide more consistent results.
Option 2: Use ICC Profiles for document color space and target color space to calculate a DeviceLink “on-the-fly” via SmartLink, which requires a license for SmartLink. Choose the rendering intent for the calculation or select the output intent of the PDF/X file under Prefer Output Intent.
When using the SmartLink option, either a DeviceLink profile is created “on-the-fly” or a stored DeviceLink profile is used depending on the setting under Profile Assignments. Store the specific profile in the table in the Profile Assignments window to ensure that a specific DeviceLink profile is applied in the configuration.
The color depth of the input data is preserved with the conversion unless TIFF, PSD or PSB files are changed into JPEG files under Options/ Image Quality. This will result in a color depth of 8 bit since only 8 bit is possible in JPEG files. Read more about this under Configuration > Options > Image Quality.
Selecting Setup Modes
After starting ZePrA, select the Auto Setup button from the Navigation Panel. The Auto Setup wizard allows creation of a queue for optimizing PDF files with just a few clicks.
There are six different setup modes for creating queues due to various condition possibilities:
Normalize and Convert Colors to new Output Condition
The content of the PDF file is first normalized to the document color space or output intent if available and then color converted to the required output condition using DeviceLink profile(s).
Two options are available:
Option 1: Use Existing DeviceLink Profile: Select the desired DeviceLink profile which will convert from the Document Color Space to the new output condition. All other options for RGB, CMYK, Gray and LAB color spaces will be automatically set.
Option 2: Use SmartLink. Calculate the ICC profiles that were selected as the Document Color Space and Target Color Space to a DeviceLink “on-the-fly”. The SmartLink license is included in the ZePrA L package or above.
Choose the Rendering Intent for the calculation. [For further information, view Automatic Configuration Wizard / Use SmartLink/Rendering Intent] Prefer Output Intent allows selection of the output intent of the PDF/X file instead of the manually set document color space.
About the process:
RGB objects with embedded profiles are color converted to the CMYK color space of the document and then the entire document is further processed via the DeviceLink profile. Embedded profiles and rendering intents in RGB objects are taken into account. When normalizing, all images that do not have an embedded profile are color converted to the document color space using the sRGB profile. Black point compensation is generally activated for the event that the embedded intent is relative colorimetric.
CMYK objects with embedded profiles are always converted to the document color space first (normalized). If the SmartLink function is enabled and an individual PDF object has an embedded device profile, the device profile is not used but the profile information is taken into account during conversion via the DeviceLink profile (SmartLink).
If a relative colorimetric rendering intent is active in the PDF object, ZePrA performs conversion with black point compensation as standard
If the DeviceLink profile was calculated with the option for preserving pure primary and secondary colors, this option ensures that pure colors remain pure in CMYK objects with embedded profiles.
After normalization, the PDF document is color converted via the DeviceLink set under Document Color Space. If SmartLink has not been purchased, direct ICC based conversion to the target profile or document color space is performed. Pure CMYK colors are almost always contaminated in the process, leading to problems with overprinting elements. The procedure of first normalizing and then color converting delivers the most consistent results for color conversion as it is recommended in the PDF/X specification.
Normalize Color to Document Color Space or Output Intent
When normalizing, the color spaces of the image data or individual PDF objects that do not correspond to the document color space or output intent are correctly converted to the output intent in most cases. If there is not an output intent, the document color space selected is used instead. After conversion, the final normalized file still only consists of the document color space or the color space of the output intent, as well as any spot colors.
If image data or PDF objects are in the RGB color space, the embedded profile converts them to the document color space with the rendering intent defined in the PDF.
If a relative colorimetric intent is embedded in PDF objects, the Auto Setup queue automatically activates black point compensation to ensure clean reproduction of details in the shadows. The default name of this queue begins with Normalize. The following color conversions apply when normalizing:
- Conversions of Device RGB and iCC based RGB to the document color space
- Spot colors are unchanged
- Conversion of ICC based CMYK to the document color space, preserving pure colors and the separation characteristics (when using the SmartLink function)
- Mapping of ICC based Gray onto the black channel of the document color space
The data is normalized to the document color space and then optimized with a predefined SaveInk profile or the SmartLink Ink saving method specified.
Choosing a SaveInk method
When Save Ink is applied the source and target profiles are identical, the optimized file stays in the same color space as the document color space. The focus is accurate reproduction of files, while simultaneously reducing the CMY components and increasing the K components in order to save ink.
The default queue name starts with SaveInk.
Use Existing DeviceLink Profile: Choose an existing Save Ink DeviceLink profile from the dropdown menu. ZePrA will only show profiles whose source and target profile are identical.
Use SmartLink: Choose the profile which matches the document color space and choose from one of the three standard ZePrA SmartLink methods (SaveNeutral, SaveStrong, SaveMaximum). Any customized SmartLink SaveInk setting generated in CoPrA (see more under Sharing settings with ZePrA) and shared with ZePrA will show below the dotted line (copra_extreme).
Calculate Ink Saving: The Auto Setup Wizard allows the option to calculate ink saving for every file processed. The calculation can slow down the processing time considerably disable this feature gaining higher performance.
Note: Ink Saving calculation can be turned off at any time via the Configurations>Options tab
Optimize Total Area Coverage (TAC)
Optimize Total Area Coverage data is normalized to the document color space and subsequently optimized using the specified TAC reduction profile or the total amount of color entered under Desired TAC when using SmartLink.
Choosing TAC Options
The source and target profiles are identical, the optimized file stays in the same color space as the document color space. The focus is on accurate file reproduction, while simultaneously reducing the ink limit.
After Optimize Total Area Coverage, select one of two options:
- Use Existing DeviceLink Profile – Select a devicelink file from the dropdown menu. Only profiles whose source and target profile are identical will be shown.
- Use SmartLink – Select the Use SmartLink option to assign a TAC to the selected Document Color Space “on-the-fly” (requires a license for SmartLink). Choose the Desired TAC for the calculation and apply the desired limitation to all output intents in different PDF/X Files.
Direct Color Conversion to New Output Condition
Converts the color of the data with embedded profiles to the required output condition (target profile) without first normalizing the data to the document color space. This mode is optimized for data prepared in a media-neutral fashion, e.g. with RGB image data. This setup mode, maximizes the gamut of the target color space. The image and vector data differing from the document color space is directly converted to the target profile.
RGB Objects with Embedded Profiles in the PDF file are converted directly to the target color space in order to exploit the maximum color space, however the embedded profiles and rendering intents are taken into account during the process. This guarantees consistent conversion and optimization of data. RGB data without an embedded profile is assumed to be in the sRGB color space. Black point compensation is generally active in the event that the embedded intent is relative colorimetric.
In the event of direct color conversion of CMYK objects, CMYK Objects with Embedded Profiles are optimized via the DeviceLink profiles using the SmartLink function.
ZePrA has the option of deactivating color management for vector/text objects via the Images/Vectors tab (under configurations). This allows embedded profiles to be taken into account for images only and leaves vector graphics unchanged.
Choose from the following options:
- Use Existing DeviceLink Profile – converts from the document color space into the required output condition. All other options for RGB, CMYK, Gray and LAB color spaces will be set automatically.
- Use Smartlink – Calculates the ICC profiles selected as the Document Color Space and Target Color Space to a DeviceLink “on-the-fly”. Note: Choosing the Rendering Intent is necessary when using SmartLink
- Select a queue name
The default queue name starts with Output
Apply Gradation Curves Only
Apply Gradation Curves Only is specific to adjusting files for compensating for different printing conditions without CtP compensations curves in the RIP. ZePrA enables the gradation of the data to be corrected “on-the-fly” without changing the characteristic curves in the RIP.
Auto Setup Gradation options
Automatically apply gradation adjustments to existing configurations or to pure gradation workflows to be created which allows the gradation curves to affect the process colors and/or spot colors but the document color space is not changed. Applying pure gradation corrections to print-ready PDF/X 1a files that are composed of only CMYK and spot colors is the best option.
Gradation workflows have three options:
Option 1: Use Curves From External Files
Load an external file with the gradation curves for process colors and/or spot colors. ZePrA reads the gradation curves from the loaded file and assigned them automatically to the appropriate process colors. If spot color curves for defined spot color channels are also stored in the external gradation file, the ZePrA creates the corresponding spot color channels in the configuration and assigns the relevant curve to each color.
Option 2: Start with Linear External File
If no external file with gradation curves is available and the curves are to be generated during the production process, a corresponding configuration may be created in advance with initially linear curves. ZePrA will automatically create a file with linear gradation curves in the base folder of the queue, which can be overwritten late during the production process by an updated file with new curve information and immediately applied to the files in the workflow.
Option 3: Select Curves
Use static gradation curves supplied in ZePrA or use the curves created in the Create Gradation Curves window to create a configuration. Simply select the desired gradations from the options available for process colors Cyan, Magenta, Yellow and Black.
Click on the check box to Normalize data. PDF/X-3 or PDF/X-4 files that still contain RGB or CMYK objects with embedded profiles will be normalized by ZePrA and the curves will be applied to the normalized file.
Document Color Space: Select an ICC profile to use as the Document Color Space in the event that no output intent is present in the PDF file. Activate the Prefer Output Intent checkbox to ensure any existing output intent always has priority over the set document color space and is always preserved.
The default queue name starts with Gradations.