This is what a complete results report would look like when each of the fields controlling the output is specified and PDF Checker completes the review successfully.

Note the section at the top of the results output, the CHECKER_SUMMARY.

This is a summary list of the items that PDF Checker found when reviewing a PDF document, intended to be machine readable.  But you might prefer to use the JSON output format instead.

You could set up a batch process to review a set of PDF documents stored in a server directory automatically, one by one. Then, you could add a step to your batch code that would identify the PDF documents that PDF Checker found with issues or problems, create an input JSON file listing those issues or problems, and send that JSON file list to PDF Optimizer.  PDF Optimizer could then optimize each PDF document based on the items found by PDF Checker. Note that for documents that PDF Optimizer can improve, a statement appears, “canBeOptimized,” to make it easy detect documents that are candidates for optimization. The software also provides the size of the PDF source document, and a machine readable value, “sizeInBytes.” This allows you to scan the results to make decisions on document processing based on file size. For example, a PDF document that is only 10 KB probably isn’t worth optimizing.

Note that the metadata for the PDF document is provided at the top of the report. The “Trapped” parameter refers to the prepress workflow when printing in color. Trapping a document governs how the ink will appear on the page; colors are trapped by adjusting the shape of objects as they are printed on the page to avoid gaps from appearing. Trapping can be enabled by some software products that generate PDF documents, such as Adobe InDesign.

PDF Checker will determine if the PDF document claims PDF/A compliance, and provide the type of PDF/A file. If in fact the file is not PDF/A compliant, an error message will appear in the output report.

PDF Checker 2.1.0  Copyright 2018-2021 Datalogics, Inc. All Rights Reserved

Wed Mar 17 11:07:33 2021

JSON Profile: everything.json

Input Document: DocumentationExample.pdf

PDF Version: 1.7

Claimed PDF/A Type: PDF/A-2a
Conforms to Claimed PDF/A Type: False

Author: John Smith
Creation Date: 2020-Sep-08 13:13:58
Creator: Acrobat PDFMaker 15 for Word
Keywords: 
Modification Date: 2020-Sep-08 13:14:04
Producer: Adobe PDF Library 18.0
Subject: 
Title: 
Trapped: 

File Size: 393 KB

<<=CHECKER_SUMMARY_START=>>
general:born-digital
general:doess-not-conform-to-claimed-pdfa-type
general:tagged-pdf
userdata:contains-annots
userdata:contains-annots-not-for-printing
userdata:contains-metadata
userdata:contains-transparency
fonts:found-non-extractible-text
fonts:uses-base14fonts-not-embedded
fonts:uses-fonts-not-embedded
cleanup:suboptimal-compression
sizeInBytes:402518
canBeOptimized
<<=CHECKER_SUMMARY_END=>>

Optimization Assessment
    Document can be optimized with PDF Optimizer - see details below

General Results
    Errors:
         Is not PDF/A conformant, see 'claimed-pdfa-type' in the Summary section for more details.:
         Total: (1 instance)

    Information:
        Document was born digital.  It was produced from PDF authoring software and so it may contain text, images, tables, forms, and other objects.  These types of PDFs typically do not require OCR.
        Is not PDF/A conformant:
            Total: (1 instance)
        Document contains tagged content
    Checks Completed:
        acroforms-type
        born-digital
        claims-pdfe-conformance
        claims-pdfua-conformance
        claims-pdfvt-conformance
        claims-pdfx-conformance
        contains-owner-password
        contains-signature
        damaged
        does-not-conform-to-claimed-pdfa-type
        image-only
        password-protected
        pdf-v2
        tagged-pdf
        unable-to-open
        xfa-type
    How To Optimize:
        Document claims to be PDF/A-2a conformant, but it is not, try using PDF Optimizer to convert to a compliant PDF/A document. (1 instance)

Userdata Results
    Errors:
        None
    Information:
        Contains annotations:
            SubType: Link (21 instances)
        Contains annotations that are set as invisible for printing:
            SubType: Link (21 instances)
        Contains metadata:
            SubType: XML, Update region size: 2048 (1 instance)
            Total: (1 instance)
        Contains transparency:
            Total: (1 instance)
    Checks Completed:
        contains-annots
        contains-annots-not-for-printing
        contains-annots-not-for-viewing
        contains-annots-without-normal-appearances
        contains-embedded-files
        contains-metadata
        contains-optional-content
        contains-private-data
        contains-transparency
    How To Optimize:
        Annotations can be removed using PDF Optimizer to save space. (21 instances)
        Annotations not intended for printing can be removed using PDF Optimizer to save space. (21 instances)
        Metadata can be removed using PDF Optimizer to save space. (1 instance)
        XMP Metadata padding can be removed using PDF Optimizer to save space. (1 instance)
        Transparency (which is not universally supported by PDF Viewers) can be flattened using PDF Optimizer. (1 instance)

Fonts Results
    Errors:
        Uses Base 14 fonts not embedded in document:
            Arial-BoldMT (1 instance)
            ArialMT (1 instance)
            CourierNewPSMT (1 instance)
        Uses fonts not embedded in document:
            CenturyGothic (1 instance)
            CenturyGothic-Bold (1 instance)
    Information:
        Uses fonts that do not allow text to be extracted:
            HSODIF+SymbolMT, SubType: Type0 (1 instance)
    Checks Completed:
        fontdescriptor-missing-capheight
        fontdescriptor-missing-fields
        found-non-extractible-text
        uses-base14fonts-not-embedded
        uses-fonts-fully-embedded
        uses-fonts-not-embedded

Objects Results
    Errors:
        None
    Information:
        None
    Checks Completed:
        contains-javascript-actions
        contains-thumbnails

Cleanup Results
    Errors:
        None
    Information:
        Contains conservatively compressed streams:
            Uncompressed: (1 instance)
    Checks Completed:
        suboptimal-compression

Image Results
    Errors:
        None
    Information:
        None
    Checks Completed:
        alternate-images

    Color Images
    Errors:
        None
    Information:
        None
    Checks Completed:
        image-depth
        resolution-too-high
        resolution-too-low
        uses-jpeg2000-compression

    Grayscale Images
    Errors:
        None
    Information:
        None
    Checks Completed:
        resolution-too-high
        resolution-too-low
        uses-jpeg2000-compression

    Monochrome Images
    Errors:
        None
    Information:
        None
    Checks Completed:
        resolution-too-high
        resolution-too-low
        uses-jbig2-compression