Output

Step 5: Using @media print for PDF-Specific Styles

When generating PDFs, you may want different styling than what appears on a webpage. The @media print rule helps:

@media print {
    body { font-size: 12px; }
    .hide-in-print { display: none; }
}

This ensures an optimized print output. It adjusts font sizes and removes unnecessary elements such as buttons and links from the final PDF output, ensuring a clean, well-formatted, and easy-to-read PDF.

Step 6: Using JavaScript for Dynamic Content

IronPDF can execute JavaScript before rendering, making it ideal for dynamic charts, graphs, and real-time data visualization.

Example: Rendering a JavaScript-Based Chart

var renderer = new ChromePdfRenderer();
var htmlContent = @"
    
        
            
        
        
            
            
        
    ";


renderer.RenderingOptions.WaitFor.RenderDelay(3000);

var pdf = renderer.RenderHtmlAsPdf(htmlContent);
pdf.SaveAs("ChartReport.pdf");

Output

4. Merging & Splitting PDFs with IronPDF

In today’s fast-paced digital world, efficient document management is essential. Merging and splitting PDFs are critical tasks for handling multi-document workflows such as batch reports, invoices, and contract management. Let’s explore why these capabilities matter and how IronPDF simplifies the process.

Why Merging & Splitting PDFs Matters

In many scenarios, the ability to merge or split PDFs is not just convenient—it’s necessary. Consider these common applications:

• Generating Monthly Reports: Consolidate individual department summaries into a single, comprehensive report, making it easier to analyze and present data.
• Combining Invoices: Gather multiple invoices into one document for a streamlined customer statement, reducing clutter and simplifying billing.
• Splitting Large PDFs: Break down extensive documents into smaller, more manageable files for better accessibility and focused review.
• Extracting Key Sections: Select specific parts of legal contracts for targeted review or sharing, ensuring that only relevant information is circulated.

With IronPDF, these tasks become effortless, eliminating the need for tedious manual processing and enhancing overall productivity.

Step 1: Merging Multiple PDFs

Merging PDFs allows you to consolidate related documents seamlessly into one cohesive file. For example, let’s combine two separate reports, report-q1.pdf and report-q2.pdf, into a single document.

var pdf1 = PdfDocument.FromFile("report-q1.pdf");
var pdf2 = PdfDocument.FromFile("report-q2.pdf");

// Merge the PDFs into a new document
var mergedPdf = PdfDocument.Merge(pdf1, pdf2);
mergedPdf.SaveAs("MergedReport.pdf");

Output

How It Works (Behind-the-Scenes)

• Loading Existing PDFs: PdfDocument.FromFile(“report-q1.pdf”) loads each specified PDF into memory, making it ready for processing.
• Combining Multiple PDFs: PdfDocument.Merge(pdf1, pdf2); effectively joins the pages of the second document at the end of the first, ensuring that their original formatting remains intact.
• Saving the Final Document: mergedPdf.SaveAs(“MergedReport.pdf”); writes the newly created PDF to disk, preserving all structural elements, images, and styles from the original files.

Step 2: Merging Multiple PDFs Dynamically

Instead of merging PDFs one by one, you can streamline the process by dynamically merging an entire list of PDFs. This is especially useful for handling large batches.

var pdfFiles = new[] { "report-q1.pdf", "report-q2.pdf", "report-q3.pdf" };
var pdfDocuments = pdfFiles.Select(file => PdfDocument.FromFile(file)).ToList();

// Merge all PDFs in the list
var mergedPdf = PdfDocument.Merge(pdfDocuments);
mergedPdf.SaveAs("FullQuarterlyReport.pdf");

Output

Why This is Useful?

• Automation: This approach automates the merging process, eliminating the need to specify each file manually.
• Scalability: Whether you have 3 or 300 PDFs to merge, the same code applies, making it highly versatile.
• Ideal for Batch Processing: Perfect for enterprise document workflows where efficiency is paramount.

Step 3: Splitting PDFs into Individual Pages

In some situations, you may need to extract pages from a PDF—whether for legal documentation, report summaries, or customer invoices. The below code demonstrates how to split an existing 10-page PDF into separate files:

var pdf = PdfDocument.FromFile("AnnualReport.pdf");

// Split into individual files
foreach (var page in pdf.Pages)
{
    var newPdf = pdf.CopyPage(page.PageIndex);
    newPdf.SaveAs("Page" + page.PageIndex + ".pdf");
}

Output

What This Does:

• Reading an Existing Multi-Page PDF: PdfDocument.FromFile("AnnualReport.pdf"); loads the specified document into memory.
• Splitting into Separate One-Page PDFs: Using a foreach loop to loop through each of the pages within our multi-paged PDF document, we split each page away from the original PDF using pdf.CopyPage(), which will copy the page located at the current index of the loop. Then, we save each extracted page as a new PDF.

This shows how easy it is to split your multi-paged PDF files into separate, new PDF files.

Step 4: Extracting a Specific Range of Pages

Sometimes, you only need to extract a specific section of a PDF. For example, to extract 4 and 5 from our 10-page document:

var pdf = PdfDocument.FromFile("AnnualReport.pdf");

var pages45doc = pdf.CopyPages(4, 5);

pages45doc.SaveAs("AnnualReport-Pages4and5.pdf");

Output

Why This is Useful?

• Focused Sharing: Saves only the relevant pages, making it ideal for sending contract excerpts or invoice sections to clients.
• Preserving Formatting: All formatting—including images, text, and styles—remains intact, ensuring the extracted content is professional and presentable.

Common Issues & Fixes

While working with PDFs, you may encounter a few common issues. Here are solutions to help you troubleshoot:

Problem: Merged PDF file size is too large.

Solution: If you PDF contains images, enable compression of images within your PDF:

mergedPdf.CompressImages(40);

This reduces file size without compromising quality.

Problem: Cannot merge PDFs with different page sizes.

Solution: Standardize page sizes using:

pdf.SetPageSize(PdfPaperSize.A4);

This ensures all merged documents share the same dimensions.

5. Extracting Text & Images from PDFs with IronPDF

In today’s data-driven world, extracting content from PDFs is crucial for various applications, from data processing and search indexing to automating document workflows. IronPDF provides a robust solution for easily extracting text and images while preserving the original structure of the document, thereby eliminating the tedious process of manual data entry.

Why Extracting Data from PDFs is Essential

• Transform Reports into Searchable Text: Convert static reports into searchable documents, making it easier to index and mine data for insights.
• Automate Financial Processes: Streamline invoice handling and financial data extraction, enabling automated workflows that enhance efficiency.
• Reclaim Images for Reuse: Extract images from PDFs for use in presentations, marketing materials, or other applications, saving valuable resources.
• Enhance Search Capabilities: Implement full-text search functionality within your PDF archives, allowing for quick access to relevant information.

Step 1: Extracting All Text from a PDF

One of the most straightforward tasks is extracting all text from a PDF document.

var pdf = PdfDocument.FromFile("SampleInvoice.pdf");
string extractedText = pdf.ExtractAllText();
Console.WriteLine(extractedText);

Output

How It Works Behind the Scenes:

Loads the Entire Document: The PdfDocument.FromFile("SampleReport.pdf") command loads the full PDF into memory, preparing it for text extraction.
Preserves Document Structure: The ExtractText() method captures the text while maintaining the original layout, including spaces, line breaks, and basic formatting.
Flexible Output Options: Extracted text can be displayed in the console, logged for future reference, or stored in a database for indexing.

Step 2: Extracting Text from a Specific Page

In many scenarios, you may only need to retrieve text from a particular section of a document, rather than the entire file. For this example, we’ll take the PDF file we used in our splitting PDF files example, and extract the text from the second page.

var pdf = PdfDocument.FromFile("AnnualReport.pdf");
string extractedText = pdf.Pages[1].Text;
Console.WriteLine(extractedText);

Output

Why This is Useful:

• Targeted Content Extraction: Focus on specific sections, which is especially beneficial when dealing with multi-page reports or invoices.
• Efficiency Boost: Avoid the overhead of processing an entire document when only a small portion is needed.

Step 3: Extracting Images from PDFs

IronPDF makes it simple to extract images embedded within a PDF and save them as separate files:

PdfDocument pdf = PdfDocument.FromFile("PdfWithImages.pdf");

var extractedImage = pdf.ExtractAllImages();

for (int i = 0; i < extractedImage.Count; i++)
{
    extractedImage[i].SaveAs($"extracted-image-{i}.png");
}

Output

Why This is Useful:

• Image Reuse: Easily reclaim logos, graphs, or other images from PDFs for use in different applications.
• Automation of Image Processing: Bypass the manual task of cropping or taking screenshots of images.

Step 4: Converting a Scanned PDF to Searchable Text (OCR Integration)

When dealing with scanned documents, extracting text requires Optical Character Recognition (OCR). IronOCR enables you to convert scanned PDFs into searchable text effortlessly:

IronTesseract ocr = new IronTesseract();

using var inputPdf = new OcrPdfInput("Sample.pdf");
OcrResult result = ocr.Read(inputPdf);
Console.WriteLine(result.Text);

Output
When to Use OCR:

• Scanned Invoices & Contracts: Convert static images of invoices or contracts into editable text for better data management.
• Digitizing Old Documents: Make archival documents searchable, improving accessibility and usability.

Common Issues & Fixes

Problem: Extracted text loses formatting.

Solution: Use pdf.ExtractTextPreserveFormatting(); to keep indentation and spacing intact.

Problem: Tables not extracting correctly.

Solution: Ensure the PDF contains text-based tables instead of images, as OCR may be necessary for image-based tables.

Problem: Extracted images are low resolution.

Solution: Use pdf.ExtractImages(300); to extract images at a higher DPI for better quality.

6. Adding Watermarks & Securing PDFs with Encryption & Digital Signatures

PDFs are widely used for contracts, reports, legal agreements, and other official documents, making security a critical aspect. Whether you need to mark documents as Confidential, Draft, or Final, protect sensitive information with encryption, or ensure authenticity with digital signatures, these features help maintain document integrity and prevent unauthorized access.

IronPDF simplifies these security enhancements with minimal coding effort, allowing you to:

• Watermark PDFs for branding, confidentiality, or status marking.
• Encrypt PDFs with passwords to restrict access.
• Digitally sign PDFs to verify authenticity and prevent tampering.
• Restrict PDF permissions to disable printing, copying, or modifications.

Let’s explore how to implement these features step by step.

Step 1: Adding a Text Watermark to a PDF

Text watermarks are commonly used to indicate a document’s status (e.g., Confidential, Draft, Final) or to apply branding. They can easily be applied to existing PDF documents or new ones.

PdfDocument pdf = PdfDocument.FromFile("SampleInvoice.pdf");

string watermarkContent = "
Draft
";

pdf.ApplyWatermark(watermarkContent, rotation: 45, opacity: 75);

pdf.SaveAs("WatermarkedInvoice.pdf");

Output

How It Works (Behind the Scenes)

• Loads an existing PDF: PdfDocument.FromFile("SampleInvoice.pdf") opens the PDF document we want to apply the watermark to.
• Applies the text watermark: The text “DRAFT” is applied to our PDF, at the default positioning. We have also set the rotation to 45 degrees, and the opacity to 75%.
• Save the modified document: The original content remains unchanged, and we have saved the PDF with a new name, with the watermark added on top.

Use Case: Marking documents as Confidential, Draft, or Approved for internal use.

Tip: If the watermark is too light or dark, adjust the opacity value (e.g., 50 for lighter or 90 for a stronger effect).

Step 2: Adding an Image Watermark

For company branding, legal paperwork, or official invoices, an image watermark (such as a company logo) is more visually effective. The process to adding an image watermark is essentially identical to adding a text watermark.

PdfDocument pdf = PdfDocument.FromFile("SampleInvoice.pdf");

string watermarkContent = "";

pdf.ApplyWatermark(watermarkContent, opacity: 75, VerticalAlignment.Top, HorizontalAlignment.Right);

pdf.SaveAs("WatermarkedInvoice.pdf");

Output

Why Use an Image Watermark?

• Professional branding – Apply company logos to invoices, contracts, and reports.
• Supports PNGs with transparency – Ensures seamless blending with the document.
• Custom positioning – Adjust the vertical and horizontal alignment to place the watermark at the desired location.

Use Case: Adding company branding to invoices, legal documents, and marketing materials.

Step 3: Password-Protecting PDFs for Security

To ensure only authorized users can access a document, PDFs can be protected with passwords. IronPDF prides itself on its excellent and powerful PDF security options, so developers like you can keep your private and sensitive information free from prying eyes.

PdfDocument pdf = PdfDocument.FromFile("ConfidentialDocument.pdf");

// Apply password protection
pdf.SecuritySettings.UserPassword = "ReadOnly123";
pdf.SecuritySettings.OwnerPassword = "AdminSecure123";

pdf.SaveAs("ProctectedDocument.pdf");

Output

How It Works

• Owner Password (AdminSecure123)– Grants full control (edit, print, extract content).
• User Password (ReadOnly123) – Allows only viewing, preventing modifications.

Use Case: Protecting financial reports, HR documents, and legal contracts.

Tip: Always use a strong password to prevent brute-force attacks.

Step 4: Digitally Signing a PDF for Authenticity

A digital signature ensures the document’s authenticity and prevents unauthorized changes. Many industries, such as finance, healthcare, and law, require digitally signed PDFs for compliance.

PdfDocument pdf = PdfDocument.FromFile("ConfidentialDocument.pdf");

// Load digital signature certificate
var certificate = new PdfSignature("C:\\Users\\kyess\\AppData\\Roaming\\Adobe\\Acrobat\\DC\\Security\\IronSoftware.pfx", "Passw0rd");

// Sign the document
pdf.Sign(certificate);
pdf.SaveAs("SignedPdf.pdf");

Output

Why Digital Signatures Matter

• Authenticity – Verifies that the document is from a trusted source.
• Tamper-Proof – If modified, the signature becomes invalid.
• Industry Compliance – Required in legal, financial, and medical fields.

Use Case: Signing contracts, invoices, and legal agreements.

Step 5: Restricting PDF Permissions

You can prevent unauthorized actions like printing, copying, or editing sensitive documents.

PdfDocument pdf = PdfDocument.FromFile("ConfidentialDocument.pdf");


// Edit your PDF permissions
pdf.SecuritySettings.AllowUserAnnotations = false;
pdf.SecuritySettings.AllowUserCopyPasteContent = false;
pdf.SecuritySettings.AllowUserFormData = false;
pdf.SecuritySettings.AllowUserPrinting = PdfPrintSecurity.NoPrint;
pdf.SecuritySettings.AllowUserCopyPasteContentForAccessibility = false;

pdf.SaveAs("ProctectedDocument.pdf");

Output

Common Restrictions

• Disable Printing – Prevents unauthorized hard copies of sensitive documents.
• Disable Copying – Stops users from copying and pasting confidential content.
• Disable Modifications – Locks document content to prevent edits.

Use Case: Government records, financial reports, and proprietary research documents.

Common Issues & Fixes

Problem: Watermark appears too light or too dark.

Solution: Adjust transparency (e.g., pdf.ApplyWatermark(watermark, opacity: 50);).

Problem: Digital signature validation fails in Adobe Acrobat.

Solution: Ensure the SSL certificate is valid and issued by a trusted CA.

Problem: Password-protected PDF can still be edited.

Solution: Use an Owner Password instead of just a User Password for stronger security.

Example: An unverified signature versus a verified signature

7. Optimizing PDF Performance & Handling Large Documents Efficiently

When working with PDFs in C#, optimizing performance is crucial—especially for large documents. Without proper handling, oversized files can slow down applications, consume excessive memory, and even cause crashes.

This section explores best practices to enhance PDF performance, reduce file sizes, and efficiently process large documents using IronPDF.

Step 1: Compressing PDFs for Smaller File Sizes

One of the most effective ways to reduce PDF size is to compress the PDF itself. IronPDF provides a specialized method, CompressImages(), which can dramatically cut down the size of image-heavy PDFs without compromising on visual quality.

PdfDocument pdf = PdfDocument.FromFile("longPdf.pdf");

pdf.Compress();
pdf.SaveAs("compressedPdf.pdf");

Output

How pdf.Compress() Works:

• Removes unnecessary metadata: PDFs often contain extra data—like font definitions, embedded thumbnails, and annotations—that aren’t essential for viewing or printing. Compression strips out these extras while keeping the core structure intact.
• Optimizes image storage: Large images can be stored inefficiently. IronPDF compresses them by re-encoding to more efficient formats (like JPEG) and adjusts their resolution for a balance between visual quality and file size.
• Shrinks embedded fonts: Often, PDFs include entire font families when only a few characters are needed. IronPDF’s compression removes unused glyphs, shrinking the font size dramatically. ### Step 2: Using Efficient Image Formats & Resolution

Images, particularly high-resolution ones, can bloat a PDF’s file size, making it slower to load and render. By choosing the right image formats and resolutions, you can greatly reduce the overall file size without compromising quality.

Best Practices for PDF Images:

• Use JPEG for photos: JPEGs are ideal for photographs and scanned images. They offer excellent compression with minimal visible quality loss. Avoid formats like PNG or BMP for photos—they tend to result in unnecessarily large file sizes.
• Use PNG for logos and icons: PNGs are perfect for graphics that require sharp edges and transparency, like logos, icons, and illustrations. This format maintains clarity even with a limited color palette.
• Avoid BMP & TIFF: These formats store pixel data without compression, resulting in massive file sizes. Instead, convert BMPs and TIFFs into more efficient formats like PNG or JPEG.

PdfDocument pdf = PdfDocument.FromFile("PdfWithImages.pdf");

pdf.CompressImages(40);
pdf.SaveAs("compressedPdf.pdf");

Output

Through this method, we are able to reduce the size of the PDF by compressing the images within it, and setting a custom quality for the compressed images.

Step 3: Using Stream-Based Processing to Reduce RAM Usage

When dealing with large PDFs, loading everything into memory at once can consume vast amounts of RAM, leading to slower processing and potential memory overload. Stream-based processing allows you to handle large PDFs more efficiently by reading the document in parts, rather than all at once.

using (var inputStream = File.OpenRead("longPdf.pdf"))
{
    // Temporarily save the stream to a file
    var tempFilePath = Path.GetTempFileName();
    using (var fileStream = new FileStream(tempFilePath, FileMode.Create, FileAccess.Write))
    {
        inputStream.CopyTo(fileStream);
    }

    // Now load the PDF from the temporary file
    var pdf = PdfDocument.FromFile(tempFilePath);
    pdf.SaveAs("OptimizedFile.pdf");

    // Clean up the temporary file
    File.Delete(tempFilePath);
}

Step 4: Caching PDFs for Reuse & Faster Access

If you generate the same PDFs repeatedly, such as invoices or reports, caching them can save considerable processing time. By saving a pre-generated PDF and loading it from cache when needed, you can dramatically reduce server load and speed up response times.

ChromePdfRenderer renderer = new ChromePdfRenderer();
var cachePath = "Cache/ReportCache.pdf";

if (!File.Exists(cachePath))
{
    var pdf = renderer.RenderHtmlAsPdf("
Cached Report
");
    pdf.SaveAs(cachePath);
}

// Load cached PDF instantly
var cachedPdf = PdfDocument.FromFile(cachePath);

How This Helps:

• Eliminates redundant processing: Caching avoids reprocessing the same document multiple times, reducing server strain and improving performance.
• Improves server scalability: High-traffic applications benefit from caching, as it reduces CPU usage and accelerates response times, ensuring smooth operations even during peak loads.

Step 5: Multi-Threaded PDF Processing for High Performance

When generating or manipulating multiple PDFs simultaneously, multi-threading can drastically improve processing speed. IronPDF’s multi-threading capabilities allow you to split tasks across multiple CPU cores, speeding up batch processing.

Parallel.ForEach(pdfList, pdfFile =>
{
    var pdf = Renderer.RenderHtmlAsPdf($"
Processing {pdfFile}
");
    pdf.SaveAs($"Processed_{pdfFile}.pdf");
});