Instead of flattening transparencies, you can rasterize the entire PDF. This converts all page content into raster data, ensuring that transparencies, overprint effects, and complex constructions are reproduced correctly. The rasterized data can be saved either as a PDF or as an image file (TIFF/JPEG).
In this article, the following topics are covered:
- When PDF rasterization is useful
- General rasterize settings
- Image output settings
- Input color space settings
- Limitations of PDF rasterization
Note: PDF rasterization requires the chargeable GMG RIP Server Option.
When PDF rasterization is useful
- Stable RIP/DFE input: For testing or feeding RIP/DFE systems with simplified pixel-based files, avoiding issues from complex vector content.
- Automated image-based workflows: When TIFF or JPEG output is explicitly required for downstream automation or systems that cannot process vector/text-based PDFs.
- Soft proofs: For generating visual proofs that reliably show how transparencies, overprint effects, and complex elements will appear.
- Maximum reliability: Ensures consistent output in cases with very complex transparencies or blending constructions.
General rasterize settings
| Setting | Description |
|---|---|
| Resolution | Defines the output resolution of the rasterized file. Default resolution: 600 dpi. As a guideline, choose an image resolution about twice the print resolution (e.g., 175 LPI → 350 ppi). For digital presses, use the RIP resolution as a reference. |
| Anti-Aliasing | Smooths aliasing effects such as jagged or pixelated edges that can occur when vector graphics are rasterized or images are downsampled. Without anti-aliasing, edges may appear rough or pixelated. |
| Quality | Defines the anti-aliasing quality level. Default: 2. GMG ColorServer uses supersampling: elements are rasterized at a higher internal resolution and then downsampled to the final output resolution. The additional pixels ensure smoother edge rendering. A higher quality level increases the supersampling resolution (e.g., 720 dpi output with Quality 4 → 2880 dpi supersampling). For faster processing, use lower quality levels at high output resolutions. Maximum level: 8. |
| Filter | Specifies the filter applied during downsampling, which defines how final pixels are calculated from the supersampled image. |
| Box Filter: Preserves sharp edges and is recommended when crisp edges are the top priority. | |
| Triangle Filter: Produces smoother results than the box filter, but with slightly reduced edge sharpness. | |
| Text Filter: Special filter optimized for text and fine details during rasterization. | |
| Target Color Space | Defines the output color space used for color conversion during rasterization. Default: ISOcoated_v2_eci. |
| Input Color Space (Customize Defaults) | Allows customization of the default settings for interpreting RGB, CMYK, Gray, and Lab colors from input files. (See also: Input Color Space Settings) |
| File Output | Specifies the output file format of the rasterized document. |
| PDF: Rasterized file is written as a PDF document. | |
| Image: Rasterized file is written as an image format, either as TIFF or JPEG. |
Image output settings
| Setting | Description |
|---|---|
| File Format | Specifies the output image file format. |
| TIFF (LZW): Rasterized file is written as a TIFF image using LZW compression. | |
| TIFF (Uncompressed): Rasterized file is written as a TIFF image without compression. File size may be significantly larger than with LZW. | |
| JPEG: Rasterized file is written as a JPEG image with lossy compression. This may reduce quality and is therefore not recommended for spot color workflows. | |
| File Structure | Defines how rasterized pages are written to image files. |
| Single File: Each page is saved as one image file. | |
| Separate Files: Creates one image file per color channel for each page. | |
| File Naming | Opens a dialog to customize image file naming. Variables and settings can be used to define rules for automatic file naming in the workflow. |
| File Naming Variables | Drag and drop file name variables from the list on the left to the right. The file name preview shows how the resulting file name will look. The following variables are available and can be used multiple times. |
| File Name: The name of the input file without file extension. | |
| Page Number: The number of the page in the PDF (e.g. 01). | |
| Channel Name (short): Abbreviation of the color channel (e.g. C for Cyan). Useful when separate files for each channel are created. Supports Cyan, Magenta, Yellow, Black, Orange, Green, Violet, Red, and Blue. For other channels, the full name is used instead. | |
| Channel Name (long): The full name of the color channel (e.g. Cyan). Useful when separate files for each channel are created. | |
Path: Inserts a backslash as folder separator into the file name. When placed between other variables, it creates a corresponding subfolder. Example: {File Name}<Path>{Page Number}.tiff → Generates one subfolder per page, with the page number as file name. |
|
| Use Divider | Define one or more characters that will be inserted into the file name after each variable, e.g. an underscore. Example {File Name}_{Page Number}.tiff → Inserts an underscore between the file name and the page number (e.g myfile_01.tiff). |
| Remove Blanks | Removes blanks in file names and channel names. Example: PANTONE Green C → PANTONEGreenC. |
| File Name Preview | Displays a preview of the resulting file name based on the selected variables and settings. |
| Create Color Separations for All Channels (Default) | Transfers all separations contained in the input file to the output file(s). This ensures that every channel present in the original document is preserved. |
| Create Color Separations for Defined Channels | Defines which channels are written into the output file(s). For example, if your device only supports CMYK, specify Cyan, Magenta, Yellow, and Black. All other separations will be discarded. |
Input color space settings
The following table shows the available Input Color Space settings, defining how RGB, CMYK, Gray, and Lab colors from input files are interpreted.
| Setting | Description |
|---|---|
| Use Attached ICC Profile (Default) | Attached ICC profiles are used as input and converted to the target color space. For uncalibrated device colors, the behavior depends on the color space: DeviceCMYK and DeviceGray remain unchanged (linear conversion); if a CMYK Output Intent is attached, it is used for DeviceCMYK; DeviceRGB defaults to AdobeRGB. |
| Use Attached ICC Profile if Available, else the Following Profile | Attached ICC profiles are used when available. For uncalibrated device color without an attached profile, the defined ICC profile is applied as input color space. |
| Use the Following ICC Profile | The defined ICC profile is applied as input color space for all device and ICC-based color. Any attached ICC profiles are ignored. |
| Use Attached Rendering Intent (Default) | The rendering intent embedded in the PDF is used for ICC-based color conversion. If no intent is specified, Relative Colorimetric is assumed. |
| Use the Following Rendering Intent | The selected rendering intent is applied for ICC-based color conversion. Available options: Relative, Perceptual, Absolute, Saturation, Black Point Compensation. |
Best practices for input color spaces
Which input color space settings are suitable depends on the characteristics of your files and on the processing steps performed before and after rasterization.
- When using Rasterize standalone and the final output condition is not defined, we recommend choosing a common exchange space such as ISO Coated v2 or eciCMYK as the target color space.
- For RGB, use attached ICC profiles and rendering intents whenever possible and define a fallback ICC profile for uncalibrated objects. If most of your customers work in AdobeRGB, define this as fallback. Otherwise, sRGB may be a safe choice, as it is the default in many design applications.
- For CMYK, consider the intended output condition of the incoming files. If they contain only DeviceCMYK and the output already matches the target, no conversion is required. If ICC-based CMYK appears only in images, a standard ICC conversion may be acceptable. If vector objects contain ICC-based CMYK, conversion might lead to issues. In such cases, normalizing the files first and using ICC Replacement rules with DeviceLink profiles is recommended.
- If rasterization is followed by further color conversion, ensure the rasterization target color space matches the input color space of the conversion profile in the color template.
Limitations of PDF rasterization
- File size: Rasterized files may become very large depending on resolution and compression.
- Loss of editability: All vectors and text are converted to pixels, leaving no editable objects.
- Resolution dependency: Output quality depends on the chosen resolution. Too low → blurred edges; too high → very large files and longer processing.
- Color separations: Spot colors are rasterized into pixel channels, which may reduce flexibility for spot workflows.
- JPEG output: Lossy image compression can reduce quality; not recommended for spot color jobs.
Comments
0 comments
Please sign in to leave a comment.