diff --git a/imageio/imageio-tiff-jai-interop/pom.xml b/imageio/imageio-tiff-jai-interop/pom.xml
new file mode 100644
index 00000000..29037ff9
--- /dev/null
+++ b/imageio/imageio-tiff-jai-interop/pom.xml
@@ -0,0 +1,56 @@
+<?xml version="1.0"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>com.twelvemonkeys.imageio</groupId>
+        <artifactId>imageio</artifactId>
+        <version>3.8.0-SNAPSHOT</version>
+    </parent>
+    <artifactId>imageio-tiff-jai-interop</artifactId>
+    <name>TwelveMonkeys :: ImageIO :: TIFF/JAI Metadata Interop</name>
+    <description>
+        Test TIFF plugin and JAI TIFF plugin Metadata interoperability
+    </description>
+
+    <properties>
+        <project.jpms.module.name>com.twelvemonkeys.imageio.jaiinterop</project.jpms.module.name>
+    </properties>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-deploy-plugin</artifactId>
+                <configuration>
+                    <skip>true</skip>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.github.jai-imageio</groupId>
+            <artifactId>jai-imageio-core</artifactId>
+            <version>1.4.0</version>
+        </dependency>
+        <dependency>
+            <groupId>com.twelvemonkeys.imageio</groupId>
+            <artifactId>imageio-core</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>com.twelvemonkeys.imageio</groupId>
+            <artifactId>imageio-core</artifactId>
+            <type>test-jar</type>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.twelvemonkeys.imageio</groupId>
+            <artifactId>imageio-metadata</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>com.twelvemonkeys.imageio</groupId>
+            <artifactId>imageio-tiff</artifactId>
+        </dependency>
+    </dependencies>
+</project>
diff --git a/imageio/imageio-tiff-jai-interop/src/test/java/com/twelvemonkeys/imageio/plugins/tiff/jaiinterop/TIFFImageMetadataJAInteroperabilityTest.java b/imageio/imageio-tiff-jai-interop/src/test/java/com/twelvemonkeys/imageio/plugins/tiff/jaiinterop/TIFFImageMetadataJAInteroperabilityTest.java
new file mode 100644
index 00000000..31cdce2c
--- /dev/null
+++ b/imageio/imageio-tiff-jai-interop/src/test/java/com/twelvemonkeys/imageio/plugins/tiff/jaiinterop/TIFFImageMetadataJAInteroperabilityTest.java
@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2021, Harald Kuhr
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * * Redistributions of source code must retain the above copyright notice, this
+ *   list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright notice,
+ *   this list of conditions and the following disclaimer in the documentation
+ *   and/or other materials provided with the distribution.
+ *
+ * * Neither the name of the copyright holder nor the names of its
+ *   contributors may be used to endorse or promote products derived from
+ *   this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package com.twelvemonkeys.imageio.plugins.tiff.jaiinterop;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+
+import java.awt.image.BufferedImage;
+import java.util.Arrays;
+import java.util.Iterator;
+
+import javax.imageio.ImageIO;
+import javax.imageio.ImageTypeSpecifier;
+import javax.imageio.ImageWriter;
+import javax.imageio.metadata.IIOMetadata;
+import javax.imageio.metadata.IIOMetadataFormatImpl;
+import javax.imageio.metadata.IIOMetadataNode;
+
+import org.junit.Test;
+
+import com.twelvemonkeys.imageio.metadata.tiff.Rational;
+import com.twelvemonkeys.imageio.metadata.tiff.TIFF;
+import com.twelvemonkeys.imageio.metadata.tiff.TIFFEntry;
+import com.twelvemonkeys.imageio.plugins.tiff.TIFFImageMetadata;
+
+/**
+ * Tests our TIFFImageMetadata works with JAI TIFFImageWriter.
+ *
+ * @author <a href="mailto:harald.kuhr@gmail.com">Harald Kuhr</a>
+ * @author last modified by $Author: haraldk$
+ * @version $Id: TIFFImageReaderJDKJPEGInteroperabilityTest.java,v 1.0 08.05.12 15:25 haraldk Exp$
+ */
+public class TIFFImageMetadataJAInteroperabilityTest {
+    private static final String JAI_TIFF_PROVIDER_CLASS_NAME = "com.github.jaiimageio.impl.plugins.tiff.TIFFImageWriterSpi";
+
+    private ImageWriter getJAIImageWriter() {
+        Iterator<ImageWriter> writers = ImageIO.getImageWritersByFormatName("TIFF");
+
+        if (writers.hasNext()) {
+            ImageWriter writer = writers.next();
+
+            if (JAI_TIFF_PROVIDER_CLASS_NAME.equals(writer.getOriginatingProvider().getClass().getName())) {
+                return writer;
+            }
+        }
+
+        throw new AssertionError("Expected Spi not found (dependency issue?): " + JAI_TIFF_PROVIDER_CLASS_NAME);
+    }
+
+
+    @Test
+    public void testRationalNeedsDenominator() {
+        // Set the resolution to 200 dpi
+        IIOMetadata ourMetadata = new TIFFImageMetadata(Arrays.asList(new TIFFEntry(TIFF.TAG_RESOLUTION_UNIT, 2), // Unit DPI (default)
+                                                                      new TIFFEntry(TIFF.TAG_X_RESOLUTION, new Rational(200)),
+                                                                      new TIFFEntry(TIFF.TAG_Y_RESOLUTION, new Rational(200))));
+
+        ImageTypeSpecifier type = ImageTypeSpecifier.createFromBufferedImageType(BufferedImage.TYPE_BYTE_GRAY);
+        ImageWriter writer = getJAIImageWriter();
+        IIOMetadata converted = writer.convertImageMetadata(ourMetadata, type, null);
+
+        assertNotNull(converted);
+
+        // Make sure we have x/y resolution in converted metadata
+        IIOMetadataNode standardTree = (IIOMetadataNode) converted.getAsTree(IIOMetadataFormatImpl.standardMetadataFormatName);
+        String horizontalPixelSize = ((IIOMetadataNode) standardTree.getElementsByTagName("HorizontalPixelSize").item(0)).getAttribute("value");
+        String verticalPixelSize = ((IIOMetadataNode) standardTree.getElementsByTagName("VerticalPixelSize").item(0)).getAttribute("value");
+
+        // For some reason this is *pixel size* in *mm*...
+        String expected = String.valueOf(2.54 / 200 * 10);
+        assertEquals(expected, horizontalPixelSize);
+        assertEquals(expected, verticalPixelSize);
+    }
+}
diff --git a/imageio/imageio-tiff-jdk-interop/src/test/java/com/twelvemonkeys/imageio/plugins/jpeg/jdkinterop/TIFFImageReaderJDKJPEGInteroperabilityTest.java b/imageio/imageio-tiff-jdk-interop/src/test/java/com/twelvemonkeys/imageio/plugins/tiff/jdkinterop/TIFFImageReaderJDKJPEGInteroperabilityTest.java
similarity index 98%
rename from imageio/imageio-tiff-jdk-interop/src/test/java/com/twelvemonkeys/imageio/plugins/jpeg/jdkinterop/TIFFImageReaderJDKJPEGInteroperabilityTest.java
rename to imageio/imageio-tiff-jdk-interop/src/test/java/com/twelvemonkeys/imageio/plugins/tiff/jdkinterop/TIFFImageReaderJDKJPEGInteroperabilityTest.java
index cce05aa5..78e74370 100644
--- a/imageio/imageio-tiff-jdk-interop/src/test/java/com/twelvemonkeys/imageio/plugins/jpeg/jdkinterop/TIFFImageReaderJDKJPEGInteroperabilityTest.java
+++ b/imageio/imageio-tiff-jdk-interop/src/test/java/com/twelvemonkeys/imageio/plugins/tiff/jdkinterop/TIFFImageReaderJDKJPEGInteroperabilityTest.java
@@ -28,25 +28,26 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-package com.twelvemonkeys.imageio.plugins.jpeg.jdkinterop;
+package com.twelvemonkeys.imageio.plugins.tiff.jdkinterop;
 
-import com.twelvemonkeys.imageio.plugins.tiff.TIFFImageReader;
-import com.twelvemonkeys.imageio.plugins.tiff.TIFFImageReaderSpi;
-import com.twelvemonkeys.imageio.util.ImageReaderAbstractTest;
+import static org.junit.Assert.fail;
 
-import org.junit.Ignore;
-import org.junit.Test;
-
-import javax.imageio.ImageIO;
-import javax.imageio.ImageReader;
-import javax.imageio.spi.ImageReaderSpi;
 import java.awt.*;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 
-import static org.junit.Assert.fail;
+import javax.imageio.ImageIO;
+import javax.imageio.ImageReader;
+import javax.imageio.spi.ImageReaderSpi;
+
+import org.junit.Ignore;
+import org.junit.Test;
+
+import com.twelvemonkeys.imageio.plugins.tiff.TIFFImageReader;
+import com.twelvemonkeys.imageio.plugins.tiff.TIFFImageReaderSpi;
+import com.twelvemonkeys.imageio.util.ImageReaderAbstractTest;
 
 /**
  * Tests our TIFFImageReader delegating to the JDK JPEGImageReader.
diff --git a/imageio/imageio-tiff/src/main/java/com/twelvemonkeys/imageio/plugins/tiff/TIFFImageMetadata.java b/imageio/imageio-tiff/src/main/java/com/twelvemonkeys/imageio/plugins/tiff/TIFFImageMetadata.java
index 41d45c40..21872699 100644
--- a/imageio/imageio-tiff/src/main/java/com/twelvemonkeys/imageio/plugins/tiff/TIFFImageMetadata.java
+++ b/imageio/imageio-tiff/src/main/java/com/twelvemonkeys/imageio/plugins/tiff/TIFFImageMetadata.java
@@ -100,7 +100,7 @@ public final class TIFFImageMetadata extends AbstractMetadata {
      * {@link #setFromTree(String, Node)}
      * or {@link #mergeTree(String, Node)} methods.
      */
-    public TIFFImageMetadata(final Collection<Entry> entries) {
+    public TIFFImageMetadata(final Collection<? extends Entry> entries) {
         this(new IFD(entries));
     }
 
@@ -196,7 +196,12 @@ public final class TIFFImageMetadata extends AbstractMetadata {
             elementNode.setAttribute("value", String.valueOf((Short) value & 0xFFFF));
         }
         else if (unsigned && value instanceof Integer) {
-            elementNode.setAttribute("value", String.valueOf((Integer) value & 0xFFFFFFFFl));
+            elementNode.setAttribute("value", String.valueOf((Integer) value & 0xFFFFFFFFL));
+        }
+        else if (value instanceof Rational) {
+            // For compatibility with JAI format, we need denominator
+            String rational = String.valueOf(value);
+            elementNode.setAttribute("value", rational.indexOf('/') < 0 && !"NaN".equals(rational) ? rational + "/1" : rational);
         }
         else {
             elementNode.setAttribute("value", String.valueOf(value));
diff --git a/imageio/imageio-tiff/src/test/java/com/twelvemonkeys/imageio/plugins/tiff/TIFFImageMetadataTest.java b/imageio/imageio-tiff/src/test/java/com/twelvemonkeys/imageio/plugins/tiff/TIFFImageMetadataTest.java
index f081e929..cb812472 100644
--- a/imageio/imageio-tiff/src/test/java/com/twelvemonkeys/imageio/plugins/tiff/TIFFImageMetadataTest.java
+++ b/imageio/imageio-tiff/src/test/java/com/twelvemonkeys/imageio/plugins/tiff/TIFFImageMetadataTest.java
@@ -238,8 +238,8 @@ public class TIFFImageMetadataTest {
         assertSingleNodeWithValue(entries, TIFF.TAG_ROWS_PER_STRIP, TIFF.TYPE_LONG, "5");
         assertSingleNodeWithValue(entries, TIFF.TAG_STRIP_BYTE_COUNTS, TIFF.TYPE_LONG, stripByteCounts);
         assertSingleNodeWithValue(entries, TIFF.TAG_PLANAR_CONFIGURATION, TIFF.TYPE_SHORT, "1");
-        assertSingleNodeWithValue(entries, TIFF.TAG_X_POSITION, TIFF.TYPE_RATIONAL, "0");
-        assertSingleNodeWithValue(entries, TIFF.TAG_Y_POSITION, TIFF.TYPE_RATIONAL, "0");
+        assertSingleNodeWithValue(entries, TIFF.TAG_X_POSITION, TIFF.TYPE_RATIONAL, "0/1");
+        assertSingleNodeWithValue(entries, TIFF.TAG_Y_POSITION, TIFF.TYPE_RATIONAL, "0/1");
         assertSingleNodeWithValue(entries, 32995, TIFF.TYPE_SHORT, "0"); // Matteing tag, obsoleted by ExtraSamples tag in TIFF 6.0
     }
 
@@ -299,7 +299,7 @@ public class TIFFImageMetadataTest {
         // Validate there's one and only one resolution unit, x res and y res
         // Validate resolution unit == 1, x res & y res
         assertSingleNodeWithValue(fields, TIFF.TAG_RESOLUTION_UNIT, TIFF.TYPE_SHORT, String.valueOf(TIFFBaseline.RESOLUTION_UNIT_DPI));
-        assertSingleNodeWithValue(fields, TIFF.TAG_X_RESOLUTION, TIFF.TYPE_RATIONAL, "300");
+        assertSingleNodeWithValue(fields, TIFF.TAG_X_RESOLUTION, TIFF.TYPE_RATIONAL, "300/1");
         assertSingleNodeWithValue(fields, TIFF.TAG_Y_RESOLUTION, TIFF.TYPE_RATIONAL, "30001/100");
     }
 
diff --git a/imageio/pom.xml b/imageio/pom.xml
index 8c47a349..28a95309 100644
--- a/imageio/pom.xml
+++ b/imageio/pom.xml
@@ -55,6 +55,7 @@
         <module>imageio-reference</module>
         <module>imageio-jpeg-jep262-interop</module>
         <module>imageio-jpeg-jai-interop</module>
+        <module>imageio-tiff-jai-interop</module>
         <module>imageio-tiff-jdk-interop</module>
     </modules>