Common issues with PS files and how to solve them

Introduction

A PostScript (PS) file is a page description language file format used in printing and desktop publishing. PostScript files are commonly used in professional printing workflows, as they provide a high level of control over the appearance of printed materials. PS files contain instructions and commands to describe the text, images, graphics, and layout elements that need to be printed or displayed on a screen. One of the notable features of PostScript is its ability to describe the content in a resolution-independent manner, so the same PS file can be printed at various sizes losslessly. While this format was widely used in the past, today it has largely been replaced by other formats, such as PDF (Portable Document Format).

How to create a PostScript (PS) file?

Choose a tool or software that supports PostScript output.
Use the chosen software to create your content, which can include text, images, graphics, and layout elements.
Export or save it as a PostScript file.
Go to the “File” menu. → Choose “Save As” or “Export”. → Select “PostScript” or “.ps” as the file format. → Configure PostScript options related to the output, such as color management, font embedding, and resolution. → Save the file.

Pros and cons of PS files

Before going further into the article’s topic, let’s take a look at the benefits and drawbacks that the PS format has. It may help you understand if this is the format you want to use or not.

Pros	Cons
PostScript provides precise control over printing elements, giving you high-quality output, especially for professional printing applications.	These files may be complex to edit due to the detailed nature of the format. So it’s not as user-friendly as more modern formats.
Contain resolution-independent vector graphics.	PostScript is designed for static content and lacks interactivity and multimedia capabilities in comparison to PDF or HTML.
PostScript supports color management to maintain color accuracy across different devices and printing environments.	PostScript files can be relatively large, especially for documents with complex graphics or images.
Such files can embed fonts, ensuring that the correct fonts are used during printing, even if the recipient doesn’t have the same fonts installed.	PostScript files are designed for printing, so they may not be the best choice for screen-based content.
PostScript files maintain consistent layouts regardless of the output device.	PostScript is not directly supported by web browsers.
The format describes each page independently, so it is easy to rearrange or modify pages without affecting the entire document.	As technology evolves, older PostScript files might face compatibility issues with newer printers or software.

PostScript files are pretty useful for professional printing applications where precise control over output quality, color accuracy, and font consistency is essential, but it can be much less preferable for more interactive, screen-based, or general-purpose digital content.

Issues that you may face working with PS files

Problem	Description
Compatibility	Not compatible with modern software, printers, or operating systems, leading to rendering errors or unexpected results.
Font problems	Using fonts that aren’t embedded or available on the system where it’s opened, leads to the problem that the layout can be disrupted, and fonts might be substituted, affecting the appearance.
File size	Complex graphics and images lead to large PostScript file sizes, causing storage and transmission challenges.
Color management	If you don’t set color management settings properly this can result in color inconsistencies between the digital file and the printed output.
Transparency and effects	It doesn’t support transparency and some graphic effects like modern formats do. This may lead to unexpected visual outcomes.
Resolution problems	PostScript’s reliance on vectors may lead to resolution-related issues when raster images within a PostScript are printed at different sizes
Complexity	PostScript syntax is complex. Incorrectly written code can lead to errors during rendering or printing.
Conversion issues	Converting PostScript files to other formats may lead to a quality loss or unexpected changes in layout.
Printing issues	Some PS files might include printer-specific instructions that cause problems when used with different printers or output devices.
Challenge to create interactive content	The format isn’t designed for interactive content or multimedia elements.
Difficult to edit	Changing PostScript files can be challenging due to its complex syntax.
Output consistency	To get consistent output you need to fine-tune PostScript settings.

Identifying and resolving issues that may arise when working with PS file

Compatibility issues

What common compatibility issues might you encounter with PS files?

PostScript files generated for one printer model might not work correctly on a different printer model.
Older PS files might not be fully compatible with newer PostScript interpreters.
PostScript files generated on one operating system might not render correctly on a different one because of differences in font handling, encoding, and other factors.

How to deal with PS compatibility issues?

Update the PostScript interpreter and printer firmware to the latest versions available.
Test PS files on the target printer or a printer with similar capabilities before widespread distribution.
Try converting PostScript files to more widely supported formats like PDF.

Font issues

Font problems within PostScript (PS) files can lead to layout and appearance issues when the file is printed or rendered.

What font issues might you encounter with PS files?

Fonts not embedded in the PS file or not available on the printing device, lead to the printer substituting them with default or similar fonts.
Even if fonts are embedded, if the printer’s PostScript interpreter does not recognize the name or version, the font can also be substituted.
If font names or references in the PS file are spelled incorrectly, the printer might not find the correct font.
Glyphs within a font might not render correctly because of encoding mismatches or damaged font files.
If the font size specified in the PS file is not supported by the printer or if the scaling is not accurately interpreted, text sizes might be incorrect.
Kerning and ligatures might not be interpreted correctly.
Fonts with specific styles (bold, italic, underline) might not render as expected too.
Characters from languages or character sets not supported by the printer’s encoding, those characters might not display correctly.
Incorrectly written PostScript code that involves fonts can lead to errors during rendering.

Whenever possible, embed the fonts used in the PS file.
Whenever possible, use TrueType fonts (TTF) for the text.
Use widely available and standard fonts to minimize the chances of font-related problems. Fonts included with most operating systems are generally safer choices.
Print a proof or test the PS file on the intended printer.
Ensure that font names and references in the PS file are accurate.
Use the latest printer drivers and firmware.
Consider converting the PS file to PDF if it suits you.

Large-size Postscript files

How to reduce the size of large PS files?

Working with heavy PS files can be challenging due to storage limits and slow file transfers. Let’s learn some strategies to make PS files lighter:

Consider embedding only the characters of fonts that are used in the document. This can significantly reduce the size of the PS file.
Choosing standard fonts that are likely to be already installed on most systems will exclude the need for font embedding.
Convert large vector images to raster images (e.g., JPEG) with appropriate resolution for printing.
Compress images using appropriate compression methods to maintain image quality while reducing file size.
Decrease the resolution of images in the PS file, especially if the images will be printed at a small size but keep the balance and pay attention to print quality.
Simplify or optimize color management settings to reduce the amount of color information stored in the file.
Consider duplicating repeated elements instead of embedding them separately.
Try breaking complex vector graphics into smaller subsets or layers, which can be placed and combined in layout software.
Use compression techniques designed for PS files, like DSC compression or binary encoding.
Simplify text elements by reducing unnecessary formatting or elaborate font styles.
Consider converting the PS file to PDF format.

Remember that reducing the file size is important, but maintaining the quality of the final printed output is also important. Always review the final document to ensure that you did not compromise the intended design and visual quality.

Difficulties with color management of PS files

What color management issues might you have when working with PS files?

PS files might not accurately represent colors on different output devices because of the variations in color rendering capabilities.
The files might not specify the correct color space, so the colors may be shifted when printed or displayed.
PS files might not accurately convert between RGB (red, green, blue) and CMYK (cyan, magenta, yellow, black) color spaces, which affects the color appearance on print.
PS files might lack embedded color profiles with information about how colors should be rendered on different devices.
The files might not specify the correct rendering intent for color conversions. This will cause color shifts during rendering.
PostScript may not handle dithering or halftoning processes properly. This results in incorrect rendering of gradients and smooth color transitions.
Transparent elements might not blend or interact correctly with underlying colors. This can cause unexpected color results.
If the output device (printer or monitor) is not calibrated well. This can cause a mismatch in colors.
Color mismatch also happens when printers are limited in the range of colors they can reproduce due to ink or toner availability.
Differences in the color measurement devices used for calibration and profiling can result in inaccuracies when converting colors between devices.

How to solve color management difficulties?

Whenever possible, embed color profiles in the PS file. This will ensure consistent color reproduction on different devices.
Choose the appropriate rendering intent for color conversions (perceptual, relative colorimetric, etc.), that will help you achieve the desired color consistency.
Regularly calibrate monitors and printers to make them accurately represent colors.
Stick to standard color spaces like sRGB and Adobe RGB.
Have a habit of printing a proof of the PS file and comparing it to the intended design to identify any color discrepancies.
Convert PS file to PDF, if color management is critical.

Resolution issues

If images in the PS file have a low resolution, they might appear pixelated or blurry at larger sizes.
Zooming images within the PS file can lead to jagged edges and distortion.
Using images with different resolutions in the same PS file can lead to inconsistencies in image quality across the document.
Halftoned images (converted into patterns of dots for printing) can affect the overall quality.
Printing a PS file with low-resolution images can result in poor print quality, with visible pixelation and loss of detail.
Low-resolution images with gradients can exhibit banding, where smooth color transitions appear as separate bands of color.
If texts within the PS file are not created at an appropriate resolution, they might appear jagged when printed.
Incorrectly converting image resolutions while generating the PS file can lead to poor image quality.

Use images with a resolution appropriate for the intended print or display size.
Favor vector graphics for text and graphics, as they maintain quality at any size.
Check the resolution of images within the PS file to ensure they meet the requirements of the final output.
Do not enlarge images significantly within the PS file.
Use image editing software to adjust image resolution and quality before including them in the PS file.
If there are halftone patterns, ensure the settings are appropriate for the desired print quality.
Be aware of the monitor or display resolution. Low-resolution images on high-resolution displays can sometimes exaggerate image quality issues.

Issues caused by the conversion

Common issues you might encounter after converting PS files

Font substitution happens if the target format doesn’t support the same fonts as the original one. This can lead to changes in the appearance of the text.
The document layout might shift or change slightly during the conversion process.
Converting to a raster format like JPEG or PNG can lead to a loss of image quality.
PS files with transparency effects might not convert accurately to certain formats.
Complex text formatting, such as kerning and ligatures, might not remain after conversion.
Converting a PS file to a raster format might need the selection of a specific resolution. This can affect the final output of the image.
Some features or effects of the PS file might not be supported by the target format. This can cause a loss of information or unexpected behavior.
If you convert to a compressed format like PDF, there might appear artifacts related to compression settings. This can impact image and text quality.
The output file might have a significantly different file size from the input PS file.

Embed fonts in the PS file before conversion.
If possible, use lossless formats like PDF.
Make sure color profiles are correctly embedded or applied during conversions involving color spaces.
Test and preview the converted file before final distribution or printing.
Pay close attention to settings and options during the conversion process.
Keep a backup of the original PS file. Also, try to keep the original source files used to create the PS document.

Printing issues

Common issues you might encounter when printing PS files

Font substitution that leads to changes in text appearance.
Differences in color rendering between the PS file and the printer.
Low-resolution images within the PS file can appear pixelated or blurry when printed.
Scaled images or content within the PS file can look distorted.
The layout might shift, or elements might be misplaced during printing.
Incorrect page orientation (portrait vs. landscape) or paper size settings can lead to misaligned content on the printed page.
Incorrect print driver settings, such as paper type, resolution, and color settings, can result in print quality.
Incorrect or incompatible PostScript code within the PS file can cause printing errors or disruptions.
Overlapping elements with transparency or overprint settings might not render as expected.
Outdated printer firmware might not fully support certain PostScript features.

How to deal with PS file printing issues?

Embed fonts in the PS file.
Calibrate your monitor, use color profiles, and set up the printer with appropriate color settings.
Opt for high-resolution images and ensure they are properly scaled within the PS file.
Check the print driver settings, such as paper size, orientation, and quality.
Ensure that both your printer firmware and drivers are up-to-date.
Carefully review the printed output to spot any layout or content problems.
If printing issues persist, consider converting the PS file to PDF.

Error messages during printing of PS files

When printing PostScript (PS) files, you might encounter different error messages that indicate issues with the file, printer, or printing process. Most of them are typical for any format, but some are specific.

Error message	Cause	Solution
PostScript Error: undefined or Undefined Command	A file contains a command or function that the printer’s PostScript interpreter does not recognize or support.	Check the PS file for any incorrect or unsupported PostScript code. Ensure that the PS file is well-formed and compatible with the printer’s interpreter.
VMerror or VM error: dictfull	The printer’s memory (virtual memory or dictionary) is insufficient to process the PS file.	Simplify the PS file, reduce its complexity, or increase the printer’s memory allocation settings.
Syntax Error or Invalid Operand	The PS file contains syntax errors or invalid values in the PostScript code.	Review the PS file for syntax errors, misplaced brackets, or incorrect parameter values. Correct any issues before printing.
Limitcheck or Limitcheck Offending Command	The printer encountered a limit (such as a memory or stack limit) while processing a specific command.	Simplify the PS file or adjust printer settings to avoid reaching the limit.
Timeout or Timeout Error	The printer did not receive data within a specified time frame while processing the PS file.	Check cables, network connections, or communication settings. Ensure a stable connection between the computer and printer.
Paper Jam or Paper Out	There is a paper jam or the printer running out of paper.	Clear paper jams, or add the paper.
Device Communication Error	Communication issues between the computer and printer, such as connection problems.	Check cables, network connections, and printer settings. Ensure the printer is properly connected and online.
Print Spooler Error or Printer Offline	Issues with the print spooler or printer status on the computer.	Check the print spooler status, restart the spooler service, and ensure the printer is online.
File Not Found	The printer cannot locate the PS file for printing.	Ensure that the PS file is accessible and correctly referenced in the print job.
Printer Firmware Error	The printer’s firmware might be outdated or corrupted.	Update the printer’s firmware to the latest version provided by the manufacturer.

Complexity

How to debug PS files?

Begin by reviewing the PS document for any obvious syntax errors, missing brackets, or incorrect commands.
Divide the PS document into sections or pages and narrow down where the problem occurs.
Many software applications allow you to preview the print output without actually printing. It may be helpful to catch layout or content issues before generating a physical print.
Temporarily remove non-essential elements, to spot whether the issue is related to specific elements.
Temporarily comment out sections of the PS code to identify whether a particular section is causing the problem.
Use print simulation tools that allow you to see how the document will appear when printed to identify potential printing issues.
Verify that the encoding used in the PS file matches the intended language and character set.
If the PS file includes complex graphics, carefully review the paths, coordinates, and transformations applied to them.
Use Ghostscript, an interpreter for the PostScript language, to process the PS document. Its error messages can provide you with valuable insights into issues.
Consult the PostScript language specification and reference materials for guidance on specific PS commands and syntax.
Collaborate with those, who have experience with PostScript or printing to gain additional insights.
Make sure that the PS document is compatible with the version of the PostScript interpreter or printer you use.
If debugging proves extremely challenging, try to contact experts who have sufficient expertise with PostScript and printing technologies.

Conclusion

To draw the conclusion it will be good to summarize all the techniques for optimizing PostScript files, so you would not face issues when working with them.

Embed only the fonts used in the PS file or use font subsets to reduce the file size.
Whenever possible, use vector graphics instead of raster images.
Compress raster images within the PS file using appropriate compression methods.
Use images with the appropriate resolution for the intended print size.
When you rasterize vector graphics, choose appropriate resolution settings to balance quality and file size.
Use color profiles and color space conversions that are appropriate for the intended output device.
If the PS file contains repeating elements, duplicate them instead of embedding them separately for each page.
Eliminate unused or redundant elements from the PS file, such as hidden layers, unused colors, or unnecessary comments.
Review and optimize the PostScript code for efficiency. Remove redundant or unnecessary commands and optimize complex paths.
Follow the Document Structuring Conventions (DSC) to structure the PS file properly.
Consider using binary encoding (BINARY token) to compress the PostScript code within the file.
Apply compression filters to specific portions of the PS file where appropriate.
Convert PS to PDF if needed.
Always print a test version of the optimized PS file.

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