In this article, you will learn
- which Checks are available in Check-in Preflight and Fixup Templates for Images, and
- which solutions are provided to fix the detected problems.
1. Introduction
When print files are uploaded to the Workflow, the documents are checked using Check-in Preflight and Fixup Templates. This process ensures that potential errors or warnings are identified early in the production process. These errors and warnings can be displayed on the corresponding page in the Workflow and provided to the customer as a PDF report for further clarification.
The Preflight Check of the print file is performed based on the activated Checks and the severity levels defined for each individual Check – Error, Warning, or Info.
2. Available Checks for Images
To take full advantage of a Check-in Preflight and Fixup Template, the templates must first be created. A template essentially consists of Preflight and Fixup Templates. Currently, more than 58 Preflight Templates are available in the Workflow. To maintain clarity, the individual Preflight Templates are organized into various categories.
This article provides a detailed description of all Checks assigned to the category Images.
2.1. Image is overprinting
Category: Image
Description: This Check enables the identification of images set to overprint. Overprinting images may cause underlying objects to show through in print. Typically, overprinting is used intentionally for design purposes and is often applied in the layout application using a «multiply» background effect. However, such effects are often unintended by the designer and can lead to undesirable results in print. This issue should be clarified in advance with the print data creator, and approval should be obtained.
Solution: If images are incorrectly set to overprint, this can be corrected afterwards using the Fixup «Set overprinted Objects to Knockout».
Figure 1: The activated Check Image is overprinting
2.2. Image is syntactically not correctly encoded
Category: Image, PDF/X-1a, PDF/X-3, PDF/X-4, PDF/X-6
Description: This Check determines whether the data objects of image content are syntactically correct. Incorrectly encoded images can cause display problems and may be rendered incompletely or incorrectly during output.
Solution: Incorrect image data objects cannot be automatically corrected within the Workflow. To avoid potential production errors, a new, error-free print file must be requested from the data creator. Alternatively, the affected image can be extracted from the print file, edited in an image editing program – such as Adobe Photoshop – and the corrected data object can then be reinserted into the PDF file using a PDF Editor. Damaged structures of image objects are also fundamentally not permitted in any PDF/X-based workflows.
Figure 2: The activated Check Image is syntactically not correctly encoded
2.3. Resolution for Bitmap images is between
Category: Object, Image, Page Content
Description: This Check identifies which bitmap images (black-and-white images) in the print file are within the defined resolution range. In combination with the Check «Resolution of bitmap images lower than defined», images with insufficient resolution can be checked separately. Only images located within the BleedBox are checked.
Solution: To minimize the sawtooth effect in print, low-resolution images can be enhanced using the Fixup «Upscale Image Resolution», which increases their resolution.
Figure 3: The activated Check Resolution for Bitmap images is between
2.4. Resolution of bitmap images lower than defined
Category: Object, Image, Page Content
Description: This Check identifies bitmap images (black-and-white images) in the print file that have a lower resolution than the specified value. In combination with the Check «Resolution for Bitmap images is between», images with insufficient and suboptimal resolution can be checked separately. Only images located within the BleedBox are checked.
Solution: To minimize the sawtooth effect in print, low-resolution images can be enhanced using the Fixup «Upscale Image Resolution» to improve their resolution.
Figure 4: The activated Check Resolution of bitmap images lower than defined
2.5. Resolution for Grayscale or Color Images is between
Category: Object, Image, Page Content
Description: This Check identifies halftone images (grayscale or color images) in the print file that are within the defined resolution range. In combination with the Check «Resolution of grayscale or color images lower than defined», images with low resolution can be reviewed separately from those with suboptimal resolution. Only images located within the BleedBox are checked.
Solution: To reduce resolution artifacts in print, low-resolution images can be improved using the Fixup «Upscale Image Resolution».
Figure 5: The activated Check Resolution for Grayscale or Color Images is between
2.6. Resolution of gray scale or color images lower than defined
Category: Object, Image, Page Content
Description: This Check identifies halftone images (color or grayscale images) in the print file that fall below the specified resolution threshold. In combination with the Check «Resolution of Grayscale or Color Images is between», images with a too low resolution can be reviewed separately from those with insufficient resolution. Only images located within the BleedBox are checked.
Solution: To reduce resolution artifacts in print, low-resolution images can be optimized using the Fixup «Upscale Image Resolution».
Figure 6: The activated Check Resolution of gray scale or color images lower than defined
Article update: Workflow 1.20.1 – 05/2025