diff --git a/poi-ooxml/src/main/java/org/apache/poi/ooxml/POIXMLTypeLoader.java b/poi-ooxml/src/main/java/org/apache/poi/ooxml/POIXMLTypeLoader.java
index a73304d..243f1d7 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/ooxml/POIXMLTypeLoader.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/ooxml/POIXMLTypeLoader.java
@@ -54,7 +54,7 @@
         // DEFAULT_XML_OPTIONS.setUnsynchronized();
 
         Map<String, String> map = new HashMap<>();
-        map.put("http://schemas.openxmlformats.org/drawingml/2006/main", "a");
+        map.put(XSSFRelation.NS_DRAWINGML, "a");
         map.put("http://schemas.openxmlformats.org/drawingml/2006/chart", "c");
         map.put("http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawing", "wp");
         map.put(PackageNamespaces.MARKUP_COMPATIBILITY, "ve");
diff --git a/poi-ooxml/src/main/java/org/apache/poi/xslf/model/ParagraphPropertyFetcher.java b/poi-ooxml/src/main/java/org/apache/poi/xslf/model/ParagraphPropertyFetcher.java
index e74615d..c2731ad 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/xslf/model/ParagraphPropertyFetcher.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/xslf/model/ParagraphPropertyFetcher.java
@@ -20,6 +20,7 @@
 package org.apache.poi.xslf.model;
 
 import static org.apache.poi.ooxml.util.XPathHelper.selectProperty;
+import static org.apache.poi.xssf.usermodel.XSSFRelation.NS_DRAWINGML;
 import static org.apache.poi.xssf.usermodel.XSSFRelation.NS_PRESENTATIONML;
 
 import java.util.function.Consumer;
@@ -46,7 +47,7 @@
 
 
     static final String PML_NS = NS_PRESENTATIONML;
-    static final String DML_NS = "http://schemas.openxmlformats.org/drawingml/2006/main";
+    static final String DML_NS = NS_DRAWINGML;
 
     private static final QName[] TX_BODY = { new QName(PML_NS, "txBody") };
     private static final QName[] LST_STYLE = { new QName(DML_NS, "lstStyle") };
diff --git a/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFRelation.java b/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFRelation.java
index c60905b..cec0e47 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFRelation.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFRelation.java
@@ -26,12 +26,13 @@
 import org.apache.poi.ooxml.POIXMLRelation;
 import org.apache.poi.sl.usermodel.PictureData.PictureType;
 import org.apache.poi.util.Beta;
+import org.apache.poi.xssf.usermodel.XSSFRelation;
 import org.apache.poi.xssf.usermodel.XSSFWorkbook;
 
 @SuppressWarnings({"unused", "WeakerAccess"})
 @Beta
 public final class XSLFRelation extends POIXMLRelation {
-    /* package */ static final String NS_DRAWINGML = "http://schemas.openxmlformats.org/drawingml/2006/main";
+    /* package */ static final String NS_DRAWINGML = XSSFRelation.NS_DRAWINGML;
 
     /**
      * A map to lookup POIXMLRelation by its relation type
diff --git a/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFShape.java b/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFShape.java
index fe6572d..1dbaee5 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFShape.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/xslf/usermodel/XSLFShape.java
@@ -60,6 +60,7 @@
 import org.openxmlformats.schemas.presentationml.x2006.main.CTShape;
 import org.openxmlformats.schemas.presentationml.x2006.main.STPlaceholderType;
 
+import static org.apache.poi.xssf.usermodel.XSSFRelation.NS_DRAWINGML;
 import static org.apache.poi.xssf.usermodel.XSSFRelation.NS_PRESENTATIONML;
 
 /**
@@ -73,7 +74,7 @@
         T parse(XMLStreamReader reader) throws XmlException;
     }
 
-    static final String DML_NS = "http://schemas.openxmlformats.org/drawingml/2006/main";
+    static final String DML_NS = NS_DRAWINGML;
     static final String PML_NS = NS_PRESENTATIONML;
 
     private static final QName[] NV_CONTAINER = {
diff --git a/poi-ooxml/src/main/java/org/apache/poi/xssf/model/ParagraphPropertyFetcher.java b/poi-ooxml/src/main/java/org/apache/poi/xssf/model/ParagraphPropertyFetcher.java
index 00f40f7..3e9b1bd 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/xssf/model/ParagraphPropertyFetcher.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/xssf/model/ParagraphPropertyFetcher.java
@@ -24,6 +24,8 @@
 import org.apache.xmlbeans.XmlObject;
 import org.apache.poi.util.Internal;
 
+import static org.apache.poi.xssf.usermodel.XSSFRelation.NS_DRAWINGML;
+
 /**
  *  Used internally to navigate the paragraph text style hierarchy within a shape and fetch properties
 */
@@ -54,7 +56,7 @@
 
         XmlObject[] o = shape.selectPath(
                 "declare namespace xdr='http://schemas.openxmlformats.org/drawingml/2006/spreadsheetDrawing' " +
-                "declare namespace a='http://schemas.openxmlformats.org/drawingml/2006/main' " +
+                "declare namespace a='" + NS_DRAWINGML + "' " +
                 ".//xdr:txBody/a:lstStyle/a:lvl" + (_level + 1) + "pPr"
         );
         if (o.length == 1) {
diff --git a/poi-ooxml/src/test/java/org/apache/poi/xddf/usermodel/TestXDDFColor.java b/poi-ooxml/src/test/java/org/apache/poi/xddf/usermodel/TestXDDFColor.java
index 7eb01c2..e4b7fa0 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/xddf/usermodel/TestXDDFColor.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/xddf/usermodel/TestXDDFColor.java
@@ -17,6 +17,7 @@
 
 package org.apache.poi.xddf.usermodel;
 
+import static org.apache.poi.xssf.usermodel.XSSFRelation.NS_DRAWINGML;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
@@ -38,7 +39,7 @@
 import org.xmlunit.diff.Diff;
 
 class TestXDDFColor {
-    private static final String XMLNS = "xmlns:a=\"http://schemas.openxmlformats.org/drawingml/2006/main\"/>";
+    private static final String XMLNS = "xmlns:a=\"" + NS_DRAWINGML + "\"/>";
 
     @Test
     void testSchemeColor() throws IOException {
diff --git a/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestXSSFDrawing.java b/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestXSSFDrawing.java
index 807a6bc..d689226 100644
--- a/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestXSSFDrawing.java
+++ b/poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestXSSFDrawing.java
@@ -16,6 +16,7 @@
 ==================================================================== */
 package org.apache.poi.xssf.usermodel;
 
+import static org.apache.poi.xssf.usermodel.XSSFRelation.NS_DRAWINGML;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
@@ -165,7 +166,7 @@
         // Ensure it got the right namespaces
         String xml = ctDrawing.toString();
         assertTrue(xml.contains("xmlns:xdr=\"http://schemas.openxmlformats.org/drawingml/2006/spreadsheetDrawing\""));
-        assertTrue(xml.contains("xmlns:a=\"http://schemas.openxmlformats.org/drawingml/2006/main\""));
+        assertTrue(xml.contains("xmlns:a=\"" + NS_DRAWINGML + '\"'));
 
         checkRewrite(wb2);
         wb2.close();