How to Configure PDF Optimizer JSON Profiles

Web, Print and Mobile Use Cases

The JSON profile is the mechanism that makes PDF Optimizer flexible. Rather than applying a fixed set of operations to every document, you define exactly what gets optimized, for which image types, with what settings, through a plain-text configuration file. The same tool that compresses a web PDF can produce a print-ready document or a mobile-optimized file, depending entirely on which profile you apply.

This guide walks through three real-world configuration scenarios: optimizing a large file for web distribution, producing a print-optimized document, and creating a mobile-first delivery version. For each, we explain which settings to use and why.

How JSON Profiles Work

A JSON profile is a configuration file you pass to PDF Optimizer using the -p flag. It contains key-value pairs that specify which optimization operations to apply. All settings are optional. All settings are off by default. If a setting is not in your profile, PDF Optimizer does not apply that operation.

Profile keys are lowercase. The file structure is standard JSON, which means it is easy to read, edit, version-control, and share across teams. You can maintain multiple profiles for different document types or output requirements and select the appropriate profile at processing time.

Predefined profiles are included with your PDF Optimizer download for the most common use cases. These are a useful starting point and can be modified to suit your specific requirements.

Scenario 1: Web Distribution (Large File, Screen Audience)

Use case: You have an 18 MB product brochure created for print that needs to be posted on your website and distributed by email. The target audience will view it on a desktop browser or mobile device, never print it. Your goal is to reduce file size significantly while maintaining acceptable visual quality at screen resolution.

The key settings for this scenario are:

•      Downsample color and grayscale images to 150 DPI. This is well above the resolution most screens render at, and indistinguishable from higher resolution in a browser.

•      Apply JPEG compression at quality 70 to 80. This produces significant size reduction on photographic content with minimal perceptible quality loss.

•      Downsample monochrome images to 300 DPI with JBIG2 compression.

•      Remove embedded thumbnails, JavaScript, unused bookmarks, and private data. These add file weight with no benefit in a web-distributed PDF.

•      Enable linearization. Linearized PDFs begin rendering in the browser before the full file has downloaded, improving the perceived load experience for end users.

A document like this that starts at 18 MB will typically land in the 3 to 6 MB range with this profile, depending on image content density. The visual result is indistinguishable from the original at screen resolution.

Scenario 2: Print-Optimized Document

Use case: You are producing PDFs for offset print production and need to prepare files for handoff to a print vendor or production department. Image resolution must be preserved. Color must be accurate for the press. Transparencies must be flattened for reliable RIP processing.

The key settings for this scenario are:

•      Do not downsample images. Print requires 300 DPI or higher; reducing resolution for a print document defeats the purpose.

•      Apply lossless compression (ZIP or Flate) to images where compression is needed, to reduce file size without altering pixel data.

•      Configure the appropriate ICC color profile for your press environment. If producing for standard offset, acrobat9-cmyk or an appropriate dot-gain profile (typically dot-gain-20 for standard coated stock) is the right target.

•      Enable transparency flattening. Most prepress raster image processors cannot handle live transparency, and unflattened transparencies are a common source of print production errors.

•      Remove interactive elements, JavaScript, and form fields that are not relevant to print output.

Print profiles prioritize output accuracy over file size. The resulting file may not be dramatically smaller than the original, but it will be correctly configured for production.

Scenario 3: Mobile-Optimized Document

Use case: You are distributing a document to users on mobile devices, many of whom are on cellular data connections. File size is a priority. The document will be viewed at small screen sizes. You want the fastest possible load time with acceptable quality.

The key settings for this scenario are:

•      Downsample color and grayscale images to 96 to 120 DPI. Mobile screens are typically lower density than desktop displays, and a 96 DPI image is more than sufficient for most content types on a mobile viewer.

•      Apply JPEG compression at quality 65 to 70. More aggressive than web distribution, appropriate given the screen size constraints.

•      Downsample monochrome images to 200 DPI with JBIG2 compression.

•      Strip all metadata, thumbnails, and non-essential objects aggressively.

•      Enable linearization for byte-serving: the first page renders immediately while the rest of the document continues loading in the background.

For a typical mixed-content document, a mobile profile will produce significantly smaller output than the web profile, at the cost of some quality. For most mobile viewing contexts, the quality difference is not perceptible.

Building a Custom Profile

Start with the predefined profile closest to your use case, open it in any text editor, and modify the settings that need adjustment. Refer to the JSON profile reference in the documentation for the complete list of available keys and their permitted values.

A few structural notes: all keys are lowercase, the file must be valid JSON (use a validator if you are unsure), and settings that are not included in your profile are simply not applied. You cannot accidentally enable an operation by omitting it.

Sample JSON profiles for web, print, and mobile scenarios are available in the documentation included with your PDF Optimizer download. These are a practical starting point that you can copy and modify for your own use.

Try PDF Optimizer for free and start developing better PDFs today.

Frequently Asked Questions

What is a JSON profile in PDF Optimizer?

A JSON profile is a plain-text configuration file that defines which optimization operations PDF Optimizer applies and with what parameters. You pass it to the tool using the -p flag. All settings are optional and off by default, giving you precise control over exactly what changes in each document.

Are JSON profile settings on by default?

No. All settings in a PDF Optimizer JSON profile are off by default. PDF Optimizer only applies operations that are explicitly specified in the profile you provide. This means you have complete control over what changes and nothing is applied unexpectedly.

How do I create a custom JSON profile for PDF Optimizer?

Start with one of the predefined profiles included in the download as a base, open it in a text editor, and modify the settings to match your requirements. The JSON profile reference in the documentation lists all available settings and their permitted values. All keys are lowercase and the file must be valid JSON.