Successful color management in the PDF workflow (5-5)

Dedicated PDF Tools Many vendors offer advanced tools for managing, checking, and changing PDF files. The products of Adobe, Enfocus and Lantana are typical representatives of various functions.

Adobe Inproduction. Adobe first started Inproduction in Acrobat 4.0. It provides many preflighting functions for making PDF files and modification tools that meet production requirements. The product is only version 1.0, and there are rumors that the product has disappeared. Although Inproduction can scan and record PDF 1.4 files, it is actually limited to use with Acrobat 4.05, and only supports PDF 1.3 and lower versions.

The main advantage of Inproduction is that it better identifies the ICCbased color space commonly used in device-independent PDF files. During the application process, we will find that some third-party plug-in solutions encounter compatibility issues when checking PDF files that are directly exported from the application software.

Enfocus PitStop. PitStop Professional 4.6, which costs about $400, is a tool for checking and modifying PDF files. It has most of the features of Adobe Inproduction and has an eye-catching larger toolkit for checking, correcting, and converting PDF files. In particular, it can add new page objects to existing PDF files, while also supporting the "sampling" function of other page objects, which can be used to select features such as colors and fonts. Of course, the software also has some limitations, such as font subsets and other issues.

PitStop's Inspector function can detect the type and attribute of any object in the page, and also allow the user to modify the attributes, such as re-assign the ICCbased page object's property file to the ICCbased page object. This feature is important for correcting PDF files that contain images from different software and Distill uses only the same feature file for processing. PitStop also has a "whole change" function that changes all the objects in the entire PDF document. For special colors, you can use the Image Color Matching palette to modify the image objects in the PDF file for optimal output consistency. PitStop Professional (and its $1,200 server version) is very useful for preflighting PDF files and can automatically correct many detected errors. In addition, Action Lists can also be used to complete corrective actions and automatically perform many procedures such as file reassignment. Preflight work is done using the "PDF Profiles" option, which defines in detail the features that PDF must include in a particular workflow.

Enfocus EyeDropper. The $30 EyeDropper is a tool for measuring the color values ​​of objects in PDF files. It can show the percentage of color or 8-bit value. It is a useful tool to ensure color quality. However, note that the software does not change the functionality of the PDF file.

Test Enfocus. The effectiveness of PitStop and EyeDropper will vary depending on the source of the PDF. For testing, we generated many device-independent PDF files using the techniques described earlier in this article, and then processed it using the now-released Enfocus tools - PitStop Pro 4.6 and EyeDropper 4.0, and noticed some anomalies.

When storing or exporting PDF files through software such as Illustrator, Photoshop, and InDesign, PitStop cannot successfully perform ICC-based color definition of imported images and original objects. Allegedly these are device-specific colors. EyeDropper also cannot define the color space of these objects correctly. While detecting the same files generated by Acrobat Inproduction, we will find that the objects are correctly tagged.

In InDesign, links to OPI and images are often problematic. If we change the OPI link in the PDF file, PitStop will display the correct ICC profile.

We should note that in all cases, the PDF file generated by Distiller for the same document will show correct color characteristics when measured using PitStop or EyeDrop. This is because PitStop must be consistent with how different applications output PDF files. Obviously, using Distiller to generate PDF files will reduce a lot of trouble.

Lantana Crackerjack 4.0. This common plug-in can be used for color printing of PDF documents. Without this feature, digital PDF files limit the amount of information that can be processed, which is useful for the display or inkjet printer proofing process, and even in many workflows can not drive the production output device.

The Crackerjack, which sells for less than $500 (and sells for less than $800 with Enfocus's PitStop Professional), is a very useful tool for printing production even without the need for color separations. It can support color separations of built-in RIP files for mixed colors, color separations, and files. Different Crackerjack window settings can be stored, and the Crackerjack Pilot can be configured to automatically process PDF files, using a combination of these settings in a hot folder. This product provides a very sophisticated and sophisticated production output demand control program, and also sets special options such as halftone screening and special angle settings.

Color conversion in Crackerjack is limited. (Similar to PitStop Pro, this symbolizes that it needs to work hard to catch up with the new version of PDF and has a possible functionality in Acrobat applications.) The ICC profile has some support features - using ICC profiles can go from RGB to CMYK conversions - but ICCbased colors in device-independent PDF files Before you use Crackerjack for output separations, be sure to convert to the target CMYK space first (using tools such as PitStop Pro).

Lantana PDF Imageworks. This $300 package is Lantana's solution designed to examine, adjust, and reconfigure files in PDF files, including the ability to edit OPI links. Since the software is mainly image-centric, it cannot check or change the color space definition of a vector or text. It can define ICC-based image encoding (including Distiller) of certain source images, but the current product version does not have the function of performing ICC-based color conversion, nor does it have the function of re-tagging and unmarking ICC-based images.

Conclusion Since the introduction of the PDF 1.2 (in Acrobat 3) version in 1996, the PDF workflow has shown great vitality in the printing and publishing arena. With the addition of the ICCbased color space in the PDF 1.3 (in Acrobat 4) version, it has become possible to archive and produce professional publications using a single digital file format.

Distiller application software plays an important role. The key to correctly marking colors using ICC profiles is to properly configure Distiller. We believe that Distiller is the most reliable way to create device-independent PDF managers that deliver the best possible color on the original target output system and a variety of different output systems such as desktop printers and calibrated displays.

Although many applications have the ability to directly store or output PDF files, the ICC-based encoding colors in PDF files from different sources are not the same. In order for most application software to produce reliable PDF files, it is recommended to first generate device-related Postscript files and then use Distiller to process them. In workflows that have used Postscript Manager for archiving and reprinting applications, converting Distriller to a device-independent PDF manager is the best choice.

Plug-in programs are necessary. The main limitation of Acrobat for high-end printing production is that it cannot directly output color separations from PDF files. This feature can be implemented using InProduction in Acrobat 4.05 or Crackerjack in 5. We believe that InProduction is a better choice for defining the color space of a PDF page object, but its version limitations are more serious.

Crackerjack has the ability to control the output of various functions, including detailed configuration of the output device, PPD and media selection. It can add printer logos and preview color separations in version 4. But basically speaking, neither of Crackerjack nor Imageworks has the sophisticated tools necessary to inspect and convert color in device- and device-independent PDF files, although both are used in professional print production.

In contrast, PitStop is very good at checking and mixing the color of PDF files—especially when dealing with files generated by Distiller. The ultimate goal, of course, is to create a workflow that marks all color objects properly in the creative process. On that day, we also need to continue studying error checking and correcting tools.
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