In this article, you will learn
- which checks for images are available in Check-in Preflight and Fixup Templates,
- which solutions are provided to resolve the issues identified.
1. Introduction
When print files are uploaded to the $PRODUCT_NAME_WORKFLOW application, the documents are checked using Check-in Preflight and Fixup Templates. This allows potential errors or warnings to be identified at an early stage, right at the beginning of the production process. These errors and warnings can be displayed on the respective page in the workflow and provided to the customer as a PDF report for further clarification.
The print file is preflighted based on the enabled checks and the severity level defined for each individual check – Error, Warning, or Info.
2. Available Checks for Images
To take full advantage of the benefits offered by a Check-in Preflight and Fixup Template, the templates must first be created. A template essentially consists of checks and fixups. Currently, more than 58 checks are available in the $PRODUCT_NAME_WORKFLOW application. To help you to maintain an overview, the individual checks have been divided into different categories.
This article provides a detailed description of all checks assigned to the Image category.
Recommended Resolution for Image Data
The required resolution of image data depends on the viewing distance. The greater the viewing distance, the lower the required resolution. A reference value of 300 dpi applies to the normal reading distance (approx. 30 cm):
- Reading distance – 300 dpi, corresponding to 100% of the reference resolution, for example for books, labels, and packaging.
- Viewing distance of approx. 1 m or more – 150 dpi, corresponding to 50% of the reference resolution, for example for displays, posters, and displays stands.
- Viewing distance of approx. 3 m or more – 75 dpi, corresponding to 25% of the reference resolution, for example for roll-ups, exhibition walls, beach flags, flags, and large-format applications.
The effective resolution at the final output size is always the decisive factor. Scaling an image changes its effective resolution accordingly. Therefore, you should always first scale the print data to the final output size before assessing whether the resolution is sufficient.
2.1. Resolution for Bitmap Images is between
Category: Object, Image, Page Content
Description: This check determines which bitmap images (black-and-white images) in the print file fall within the specified resolution range. In combination with the "Resolution of Bitmap Images lower than defined" check, images with insufficient resolution can be checked separately. Only images located within the BleedBox are checked.
Solution: To minimize the sawtooth effect in print, images with low-resolution can be upsampled to a higher resolution using the "Upscale Image Resolution" Fixup.
Figure 1: The Resolution for Bitmap Images is between check enabled
2.2. Resolution of Bitmap Images lower than defined
Category: Object, Image, Page Content
Description: This check determines which bitmap images (black-and-white images) in the print file have a lower resolution than the specified value. In combination with the "Resolution for Bitmap Images is between" check, images with insufficient resolution and images that do not have an optimal 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 upsampled using the "Upscale Image Resolution" Fixup.
Figure 2: The Resolution of Bitmap Images lower than defined check enabled
2.3. Resolution for Grayscale or Color Images is between
Category: Object, Image, Page Content
Description: This check determines which halftone images (grayscale or color images) in the print file fall within the specified resolution range. In combination with the "Resolution of Grayscale or Color Images lower than defined" check, images with low resolution can be checked separately from those with suboptimal resolution. Only images located within the BleedBox are checked.
Solution: To reduce resolution-related artifacts in print production, low-resolution images can be optimized by upsampling them to a higher resolution using the "Upscale Image Resolution" Fixup.
Figure 3: The Resolution for Grayscale or Color Images is between check enabled
2.4. Resolution of Grayscale or Color Images lower than defined
Category: Object, Image, Page Content
Description: This check determines which halftone images (grayscale or color images) in the print file have a resolution below the specified threshold. In combination with the "Resolution for Grayscale or Color Images is between" check, images with a resolution that is too low can be checked separately from images with an insufficient resolution. Only images located within the BleedBox are checked.
Solution: To reduce resolution-related artifacts in print production, images with a resolution that is too low can be optimized by upsampling them to a higher resolution using the "Upscale Image Resolution" Fixup.
Figure 4: The Resolution of Grayscale or Color Images lower than defined check enabled
2.5. 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 valid. Incorrectly encoded images may cause display issues and may be rendered incompletely or incorrectly during output.
Solution: Incorrectly encoded image data objects cannot be corrected automatically within the application. To avoid potential production errors, a new, error-free print file should be requested from the data creator. Alternatively, the affected image can be extracted from the print file, edited using an image editing application such as Adobe Photoshop or the PDF Editor, and the corrected data object can then be reinserted into the PDF file using the PDF Editor. Damaged structures within image objects are generally not permitted in any PDF/X-based workflow.
Figure 5: The Image is syntactically not correctly encoded check enabled
2.6. Image is overprinting
Category: Image
Description: This check enables the identification of images that are set to overprint. Overprinting images may cause underlying objects to show through in the printed output. In general, overprinting images are used for design purposes and are often created in the layout application by applying the "multiply" blend mode in the background. However, these effects are frequently unintended by the designer and may result in undesirable output in print. This issue should be clarified with the print data creator in advance, and approval should be obtained before production.
Solution: If images are incorrectly set to overprint, this can subsequently be resolved using the "Set overprinted Objects to Knockout" Fixup.
Figure 6: The Image is overprinting check enabled
Article update: $PRODUCT_NAME_WORKFLOW 2.3.0 – 08/2026