diff --git a/docs/index.md b/docs/index.md
index ac8963b7..0e3d6806 100644
--- a/docs/index.md
+++ b/docs/index.md
@@ -1542,7 +1542,7 @@ fast distribution of represented data.
 **PDF limitations** Please note that PDF file format has some limits
 regarding to styling cells, number formatting, ...
 
-### \PhpOffice\PhpSpreadsheet\Writer\PDF
+### \PhpOffice\PhpSpreadsheet\Writer\Pdf
 
 PhpSpreadsheet’s PDF Writer is a wrapper for a 3rd-Party PDF Rendering
 library such as tcPDF, mPDF or DomPDF. You must now install a PDF
@@ -1577,11 +1577,11 @@ Once you have identified the Renderer that you wish to use for PDF
 generation, you can write a .pdf file using the following code:
 
 ``` php
-$writer = new \PhpOffice\PhpSpreadsheet\Writer\PDF($spreadsheet);
+$writer = new \PhpOffice\PhpSpreadsheet\Writer\Pdf($spreadsheet);
 $writer->save("05featuredemo.pdf");
 ```
 
-Please note that \PhpOffice\PhpSpreadsheet\Writer\PDF only outputs the
+Please note that \PhpOffice\PhpSpreadsheet\Writer\Pdf only outputs the
 first worksheet by default.
 
 #### Write all worksheets
@@ -1609,7 +1609,7 @@ This can be slow on large spreadsheets, and maybe even unwanted. You can
 however disable formula pre-calculation:
 
 ``` php
-$writer = new \PhpOffice\PhpSpreadsheet\Writer\PDF($spreadsheet);
+$writer = new \PhpOffice\PhpSpreadsheet\Writer\Pdf($spreadsheet);
 $writer->setPreCalculateFormulas(false);
 
 $writer->save("05featuredemo.pdf");
diff --git a/samples/21_Pdf_Domdf.php b/samples/21_Pdf_Domdf.php
index 638cb2cc..44d6e972 100644
--- a/samples/21_Pdf_Domdf.php
+++ b/samples/21_Pdf_Domdf.php
@@ -14,4 +14,4 @@ $helper->log("Write to PDF format using {$rendererName}");
 \PhpOffice\PhpSpreadsheet\Settings::setPdfRendererName($rendererName);
 
 // Save
-$helper->write($spreadsheet, __FILE__, ['PDF' => 'pdf']);
+$helper->write($spreadsheet, __FILE__, ['Pdf' => 'pdf']);
diff --git a/samples/21_Pdf_TCPDF.php b/samples/21_Pdf_TCPDF.php
index 5c25fe72..53eda62a 100644
--- a/samples/21_Pdf_TCPDF.php
+++ b/samples/21_Pdf_TCPDF.php
@@ -14,4 +14,4 @@ $helper->log("Write to PDF format using {$rendererName}");
 \PhpOffice\PhpSpreadsheet\Settings::setPdfRendererName($rendererName);
 
 // Save
-$helper->write($spreadsheet, __FILE__, ['PDF' => 'pdf']);
+$helper->write($spreadsheet, __FILE__, ['Pdf' => 'pdf']);
diff --git a/samples/21_Pdf_mPDF.php b/samples/21_Pdf_mPDF.php
index 5c7cc1b0..f2734966 100644
--- a/samples/21_Pdf_mPDF.php
+++ b/samples/21_Pdf_mPDF.php
@@ -14,4 +14,4 @@ $helper->log("Write to PDF format using {$rendererName}");
 \PhpOffice\PhpSpreadsheet\Settings::setPdfRendererName($rendererName);
 
 // Save
-$helper->write($spreadsheet, __FILE__, ['PDF' => 'pdf']);
+$helper->write($spreadsheet, __FILE__, ['Pdf' => 'pdf']);
diff --git a/samples/26_Utf8.php b/samples/26_Utf8.php
index caf2a6e6..6925f567 100644
--- a/samples/26_Utf8.php
+++ b/samples/26_Utf8.php
@@ -19,7 +19,7 @@ $helper->write($spreadsheet, __FILE__, ['Xlsx' => 'xlsx', 'Xls' => 'xls', 'HTML'
 // Export to PDF (.pdf)
 $helper->log('Write to PDF format');
 \PhpOffice\PhpSpreadsheet\Settings::setPdfRendererName($rendererName);
-$helper->write($spreadsheet, __FILE__, ['PDF' => 'pdf']);
+$helper->write($spreadsheet, __FILE__, ['Pdf' => 'pdf']);
 
 // Remove first two rows with field headers before exporting to CSV
 $helper->log('Removing first two heading rows for CSV export');
diff --git a/src/PhpSpreadsheet/Helper/Migrator.php b/src/PhpSpreadsheet/Helper/Migrator.php
index 0b56d903..3912e48f 100644
--- a/src/PhpSpreadsheet/Helper/Migrator.php
+++ b/src/PhpSpreadsheet/Helper/Migrator.php
@@ -60,10 +60,10 @@ class Migrator
             'PHPExcel_Writer_OpenDocument_Styles' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Ods\\Styles',
             'PHPExcel_Writer_OpenDocument_Thumbnails' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Ods\\Thumbnails',
             'PHPExcel_Writer_OpenDocument_WriterPart' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Ods\\WriterPart',
-            'PHPExcel_Writer_PDF_Core' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\PDF\\Core',
-            'PHPExcel_Writer_PDF_DomPDF' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\PDF\\DomPDF',
-            'PHPExcel_Writer_PDF_mPDF' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\PDF\\MPDF',
-            'PHPExcel_Writer_PDF_tcPDF' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\PDF\\TcPDF',
+            'PHPExcel_Writer_PDF_Core' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Pdf\\Core',
+            'PHPExcel_Writer_PDF_DomPDF' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Pdf\\DomPDF',
+            'PHPExcel_Writer_PDF_mPDF' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Pdf\\MPDF',
+            'PHPExcel_Writer_PDF_tcPDF' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Pdf\\TcPDF',
             'PHPExcel_Writer_Excel5_BIFFwriter' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xls\\BIFFwriter',
             'PHPExcel_Writer_Excel5_Escher' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xls\\Escher',
             'PHPExcel_Writer_Excel5_Font' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xls\\Font',
@@ -201,7 +201,7 @@ class Migrator
             'PHPExcel_Writer_HTML' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\HTML',
             'PHPExcel_Writer_IWriter' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\IWriter',
             'PHPExcel_Writer_OpenDocument' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Ods',
-            'PHPExcel_Writer_PDF' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\PDF',
+            'PHPExcel_Writer_PDF' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Pdf',
             'PHPExcel_Writer_Excel5' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xls',
             'PHPExcel_Writer_Excel2007' => '\\PhpOffice\\PhpSpreadsheet\\Writer\\Xlsx',
             'PHPExcel_CachedObjectStorageFactory' => '\\PhpOffice\\PhpSpreadsheet\\CachedObjectStorageFactory',
diff --git a/src/PhpSpreadsheet/Shared/StringHelper.php b/src/PhpSpreadsheet/Shared/StringHelper.php
index 0307ab5f..f73b28fd 100644
--- a/src/PhpSpreadsheet/Shared/StringHelper.php
+++ b/src/PhpSpreadsheet/Shared/StringHelper.php
@@ -745,7 +745,7 @@ class StringHelper
 
     /**
      * Set the decimal separator. Only used by \PhpOffice\PhpSpreadsheet\Style\NumberFormat::toFormattedString()
-     * to format output by \PhpOffice\PhpSpreadsheet\Writer\HTML and \PhpOffice\PhpSpreadsheet\Writer\PDF.
+     * to format output by \PhpOffice\PhpSpreadsheet\Writer\HTML and \PhpOffice\PhpSpreadsheet\Writer\Pdf.
      *
      * @param string $pValue Character for decimal separator
      */
@@ -778,7 +778,7 @@ class StringHelper
 
     /**
      * Set the thousands separator. Only used by \PhpOffice\PhpSpreadsheet\Style\NumberFormat::toFormattedString()
-     * to format output by \PhpOffice\PhpSpreadsheet\Writer\HTML and \PhpOffice\PhpSpreadsheet\Writer\PDF.
+     * to format output by \PhpOffice\PhpSpreadsheet\Writer\HTML and \PhpOffice\PhpSpreadsheet\Writer\Pdf.
      *
      * @param string $pValue Character for thousands separator
      */
@@ -816,7 +816,7 @@ class StringHelper
 
     /**
      * Set the currency code. Only used by \PhpOffice\PhpSpreadsheet\Style\NumberFormat::toFormattedString()
-     *        to format output by \PhpOffice\PhpSpreadsheet\Writer\HTML and \PhpOffice\PhpSpreadsheet\Writer\PDF.
+     *        to format output by \PhpOffice\PhpSpreadsheet\Writer\HTML and \PhpOffice\PhpSpreadsheet\Writer\Pdf.
      *
      * @param string $pValue Character for currency code
      */
diff --git a/src/PhpSpreadsheet/Writer/HTML.php b/src/PhpSpreadsheet/Writer/HTML.php
index d8469cbd..c95d5ecc 100644
--- a/src/PhpSpreadsheet/Writer/HTML.php
+++ b/src/PhpSpreadsheet/Writer/HTML.php
@@ -1354,7 +1354,7 @@ class HTML extends BaseWriter implements IWriter
                     if (!$this->useInlineCss) {
                         $html .= ' class="' . $cssClass . '"';
                     } else {
-                        //** Necessary redundant code for the sake of \PhpOffice\PhpSpreadsheet\Writer\PDF **
+                        //** Necessary redundant code for the sake of \PhpOffice\PhpSpreadsheet\Writer\Pdf **
                         // We must explicitly write the width of the <td> element because TCPDF
                         // does not recognize e.g. <col style="width:42pt">
                         $width = 0;
diff --git a/src/PhpSpreadsheet/Writer/PDF.php b/src/PhpSpreadsheet/Writer/Pdf.php
similarity index 95%
rename from src/PhpSpreadsheet/Writer/PDF.php
rename to src/PhpSpreadsheet/Writer/Pdf.php
index 2661a143..cb16dc6b 100644
--- a/src/PhpSpreadsheet/Writer/PDF.php
+++ b/src/PhpSpreadsheet/Writer/Pdf.php
@@ -26,7 +26,7 @@ use PhpOffice\PhpSpreadsheet\Spreadsheet;
  *  @copyright   Copyright (c) 2006 - 2015 PhpSpreadsheet (https://github.com/PHPOffice/PhpSpreadsheet)
  *  @license     http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt    LGPL
  */
-class PDF implements IWriter
+class Pdf implements IWriter
 {
     /**
      * The wrapper for the requested PDF rendering engine.
@@ -49,7 +49,7 @@ class PDF implements IWriter
             throw new Exception('PDF Rendering library has not been defined.');
         }
 
-        $rendererName = '\\PhpOffice\\PhpSpreadsheet\\Writer\\PDF\\' . $pdfLibraryName;
+        $rendererName = '\\PhpOffice\\PhpSpreadsheet\\Writer\\Pdf\\' . $pdfLibraryName;
         $this->renderer = new $rendererName($spreadsheet);
     }
 
diff --git a/src/PhpSpreadsheet/Writer/PDF/Core.php b/src/PhpSpreadsheet/Writer/Pdf/Core.php
similarity index 99%
rename from src/PhpSpreadsheet/Writer/PDF/Core.php
rename to src/PhpSpreadsheet/Writer/Pdf/Core.php
index 3481697d..91fd7aa1 100644
--- a/src/PhpSpreadsheet/Writer/PDF/Core.php
+++ b/src/PhpSpreadsheet/Writer/Pdf/Core.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace PhpOffice\PhpSpreadsheet\Writer\PDF;
+namespace PhpOffice\PhpSpreadsheet\Writer\Pdf;
 
 /**
  *  Copyright (c) 2006 - 2015 PhpSpreadsheet.
diff --git a/src/PhpSpreadsheet/Writer/PDF/DomPDF.php b/src/PhpSpreadsheet/Writer/Pdf/DomPDF.php
similarity index 98%
rename from src/PhpSpreadsheet/Writer/PDF/DomPDF.php
rename to src/PhpSpreadsheet/Writer/Pdf/DomPDF.php
index 0727fdb7..54b74ed3 100644
--- a/src/PhpSpreadsheet/Writer/PDF/DomPDF.php
+++ b/src/PhpSpreadsheet/Writer/Pdf/DomPDF.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace PhpOffice\PhpSpreadsheet\Writer\PDF;
+namespace PhpOffice\PhpSpreadsheet\Writer\Pdf;
 
 /**
  *  Copyright (c) 2006 - 2015 PhpSpreadsheet.
diff --git a/src/PhpSpreadsheet/Writer/PDF/MPDF.php b/src/PhpSpreadsheet/Writer/Pdf/MPDF.php
similarity index 98%
rename from src/PhpSpreadsheet/Writer/PDF/MPDF.php
rename to src/PhpSpreadsheet/Writer/Pdf/MPDF.php
index f848eeb9..da69dc3e 100644
--- a/src/PhpSpreadsheet/Writer/PDF/MPDF.php
+++ b/src/PhpSpreadsheet/Writer/Pdf/MPDF.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace PhpOffice\PhpSpreadsheet\Writer\PDF;
+namespace PhpOffice\PhpSpreadsheet\Writer\Pdf;
 
 /**
  *  Copyright (c) 2006 - 2015 PhpSpreadsheet.
diff --git a/src/PhpSpreadsheet/Writer/PDF/TcPDF.php b/src/PhpSpreadsheet/Writer/Pdf/TcPDF.php
similarity index 98%
rename from src/PhpSpreadsheet/Writer/PDF/TcPDF.php
rename to src/PhpSpreadsheet/Writer/Pdf/TcPDF.php
index bc70208c..4fa34e0e 100644
--- a/src/PhpSpreadsheet/Writer/PDF/TcPDF.php
+++ b/src/PhpSpreadsheet/Writer/Pdf/TcPDF.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace PhpOffice\PhpSpreadsheet\Writer\PDF;
+namespace PhpOffice\PhpSpreadsheet\Writer\Pdf;
 
 /**
  *  Copyright (c) 2006 - 2015 PhpSpreadsheet.