diff --git a/gradle.properties b/gradle.properties
index f972855..55b8d93 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -1,5 +1,5 @@
 group = org.xbib.graphics
 name = graphics
-version = 4.3.2
+version = 4.3.3
 
 org.gradle.warning.mode = ALL
diff --git a/graphics-ghostscript/src/main/java/org/xbib/graphics/ghostscript/FontAnalyzer.java b/graphics-ghostscript/src/main/java/org/xbib/graphics/ghostscript/FontAnalyzer.java
index 0bcdb2c..b7f5ee0 100644
--- a/graphics-ghostscript/src/main/java/org/xbib/graphics/ghostscript/FontAnalyzer.java
+++ b/graphics-ghostscript/src/main/java/org/xbib/graphics/ghostscript/FontAnalyzer.java
@@ -23,9 +23,9 @@ public class FontAnalyzer {
                 "-sFile=" + path.toAbsolutePath(),
                 "-sOutputFile=%stdout",
                 "-f", "-"};
+        Ghostscript gs = Ghostscript.getInstance();
         try (InputStream is = this.getClass().getClassLoader().getResourceAsStream("script/AnalyzePDFFonts.ps");
              ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
-            Ghostscript gs = Ghostscript.getInstance();
             gs.setStdIn(is);
             gs.setStdOut(baos);
             gs.run(gsArgs);
@@ -56,6 +56,8 @@ public class FontAnalyzer {
                 }
             }
             return result;
+        } finally {
+            gs.close();
         }
     }
 }
diff --git a/graphics-ghostscript/src/main/java/org/xbib/graphics/ghostscript/Ghostscript.java b/graphics-ghostscript/src/main/java/org/xbib/graphics/ghostscript/Ghostscript.java
index 86c6bec..ef07044 100644
--- a/graphics-ghostscript/src/main/java/org/xbib/graphics/ghostscript/Ghostscript.java
+++ b/graphics-ghostscript/src/main/java/org/xbib/graphics/ghostscript/Ghostscript.java
@@ -31,32 +31,24 @@ public class Ghostscript {
 
     private static Ghostscript INSTANCE;
 
-    private static InputStream stdIn;
+    private InputStream stdIn;
 
-    private static OutputStream stdOut;
+    private OutputStream stdOut;
 
-    private static OutputStream stdErr;
+    private OutputStream stdErr;
 
-    static {
-        try {
-            prepareTmp();
-            INSTANCE = new Ghostscript();
-            stdOut = new LoggingOutputStream(logger);
-            stdErr = new LoggingOutputStream(logger);
-            INSTANCE.setStdOut(stdOut);
-            INSTANCE.setStdErr(stdErr);
-        } catch (Exception e) {
-            logger.log(Level.SEVERE, e.getMessage(), e);
+    private GhostscriptLibrary libraryInstance;
+
+    private Ghostscript(GhostscriptLibrary libraryInstance) {
+        this.libraryInstance = libraryInstance;
+        this.stdOut = new LoggingOutputStream(logger);
+        this.stdErr = new LoggingOutputStream(logger);
+    }
+
+    public synchronized static Ghostscript getInstance() {
+        if (INSTANCE == null) {
+            INSTANCE = createInstance();
         }
-    }
-
-    private final GhostscriptLibrary libraryInstance;
-
-    private Ghostscript() {
-        libraryInstance = GhostscriptLibraryLoader.loadLibrary();
-    }
-
-    public static Ghostscript getInstance() {
         return INSTANCE;
     }
 
@@ -65,7 +57,7 @@ public class Ghostscript {
      *
      * @return the Ghostscript revision data.
      */
-    public static GhostscriptRevision getRevision() {
+    public synchronized static GhostscriptRevision getRevision() {
         GhostscriptLibrary.gsapi_revision_s revision = new GhostscriptLibrary.gsapi_revision_s();
         INSTANCE.libraryInstance.gsapi_revision(revision, revision.size());
         GhostscriptRevision result = new GhostscriptRevision();
@@ -83,7 +75,7 @@ public class Ghostscript {
      *
      * @return The OutputStream or null
      */
-    public synchronized OutputStream getStdErr() {
+    public OutputStream getStdErr() {
         return stdErr;
     }
 
@@ -92,7 +84,7 @@ public class Ghostscript {
      *
      * @param outputStream OutputStream object
      */
-    public synchronized void setStdErr(OutputStream outputStream) {
+    public void setStdErr(OutputStream outputStream) {
         stdErr = outputStream;
     }
 
@@ -101,7 +93,7 @@ public class Ghostscript {
      *
      * @return The OutputStream or null
      */
-    public synchronized OutputStream getStdOut() {
+    public OutputStream getStdOut() {
         return stdOut;
     }
 
@@ -110,7 +102,7 @@ public class Ghostscript {
      *
      * @param outputStream OutputStream object
      */
-    public synchronized void setStdOut(OutputStream outputStream) {
+    public void setStdOut(OutputStream outputStream) {
         stdOut = outputStream;
     }
 
@@ -119,7 +111,7 @@ public class Ghostscript {
      *
      * @return The InputStream or null
      */
-    public synchronized InputStream getStdIn() {
+    public InputStream getStdIn() {
         return stdIn;
     }
 
@@ -128,7 +120,7 @@ public class Ghostscript {
      *
      * @param inputStream InputStream object
      */
-    public synchronized void setStdIn(InputStream inputStream) {
+    public void setStdIn(InputStream inputStream) {
         stdIn = inputStream;
     }
 
@@ -265,6 +257,35 @@ public class Ghostscript {
         }
     }
 
+    public synchronized void close() throws IOException {
+        if (stdIn != null) {
+            stdIn.close();
+            stdIn = null;
+        }
+        if (stdOut != null) {
+            stdOut.close();
+            stdOut = null;
+        }
+        if (stdErr != null) {
+            stdErr.close();
+            stdErr = null;
+        }
+        libraryInstance = null;
+        INSTANCE = null;
+        System.gc();
+        logger.log(Level.INFO, "ghostscript instance closed and gc'ed()");
+    }
+
+    private static Ghostscript createInstance() {
+        try {
+            prepareTmp();
+            return new Ghostscript(GhostscriptLibraryLoader.loadLibrary());
+        } catch (Exception e) {
+            logger.log(Level.SEVERE, e.getMessage(), e);
+        }
+        return null;
+    }
+
     private static void prepareTmp() throws IOException {
         String tmp = System.getenv("TMPDIR"); // the variable that ghostscript uses
         if (tmp == null) {
diff --git a/graphics-ghostscript/src/main/java/org/xbib/graphics/ghostscript/PDFConverter.java b/graphics-ghostscript/src/main/java/org/xbib/graphics/ghostscript/PDFConverter.java
index 9e5daf1..8ac2cb1 100644
--- a/graphics-ghostscript/src/main/java/org/xbib/graphics/ghostscript/PDFConverter.java
+++ b/graphics-ghostscript/src/main/java/org/xbib/graphics/ghostscript/PDFConverter.java
@@ -106,73 +106,77 @@ public class PDFConverter {
         if (outputStream == null) {
             return;
         }
-        prepare(tmpPath);
-        Path output = Files.createTempFile(tmpPath, "pdf", "pdf");
         Ghostscript gs = Ghostscript.getInstance();
-        List<String> gsArgs = new LinkedList<>();
-        gsArgs.add("-ps2pdf");
-        gsArgs.add("-dNOPAUSE");
-        //gsArgs.add("-dQUIET");
-        gsArgs.add("-dBATCH");
-        gsArgs.add("-dSAFER");
-        switch (autoRotatePages) {
-            case OPTION_AUTOROTATEPAGES_NONE:
-                gsArgs.add("-dAutoRotatePages=/None");
-                break;
-            case OPTION_AUTOROTATEPAGES_ALL:
-                gsArgs.add("-dAutoRotatePages=/All");
-                break;
-            case OPTION_AUTOROTATEPAGES_PAGEBYPAGE:
-                gsArgs.add("-dAutoRotatePages=/PageByPage");
-                break;
-            default:
-                break;
-        }
-        switch (processColorModel) {
-            case OPTION_PROCESSCOLORMODEL_CMYK:
-                gsArgs.add("-dProcessColorModel=/DeviceCMYK");
-                break;
-            case OPTION_PROCESSCOLORMODEL_GRAY:
-                gsArgs.add("-dProcessColorModel=/DeviceGray");
-                break;
-            default:
-                gsArgs.add("-dProcessColorModel=/DeviceRGB");
-                break;
-        }
-        switch (pdfsettings) {
-            case OPTION_PDFSETTINGS_EBOOK:
-                gsArgs.add("-dPDFSETTINGS=/ebook");
-                break;
-            case OPTION_PDFSETTINGS_SCREEN:
-                gsArgs.add("-dPDFSETTINGS=/screen");
-                break;
-            case OPTION_PDFSETTINGS_PRINTER:
-                gsArgs.add("-dPDFSETTINGS=/printer");
-                break;
-            case OPTION_PDFSETTINGS_PREPRESS:
-                gsArgs.add("-dPDFSETTINGS=/prepress");
-                break;
-            default:
-                gsArgs.add("-dPDFSETTINGS=/default");
-                break;
-        }
-        gsArgs.add("-dCompatibilityLevel=" + compatibilityLevel);
-        gsArgs.add("-dPDFX=" + pdfx);
-        gsArgs.add("-dDEVICEWIDTHPOINTS=" + paperSize.getWidth());
-        gsArgs.add("-dDEVICEHEIGHTPOINTS=" + paperSize.getHeight());
-        gsArgs.add("-sDEVICE=pdfwrite");
-        gsArgs.add("-sOutputFile=" + output.toAbsolutePath().toString());
-        //gsArgs.add("-q");
-        gsArgs.add("-f");
-        gsArgs.add("-");
         try {
-            gs.setStdIn(inputStream);
-            gs.setStdOut(new LoggingOutputStream(logger));
-            gs.setStdErr(new LoggingOutputStream(logger));
-            gs.run(gsArgs.toArray(new String[gsArgs.size()]));
-            Files.copy(output.toAbsolutePath(), outputStream);
+            prepare(tmpPath);
+            Path output = Files.createTempFile(tmpPath, "pdf", "pdf");
+            List<String> gsArgs = new LinkedList<>();
+            gsArgs.add("-ps2pdf");
+            gsArgs.add("-dNOPAUSE");
+            //gsArgs.add("-dQUIET");
+            gsArgs.add("-dBATCH");
+            gsArgs.add("-dSAFER");
+            switch (autoRotatePages) {
+                case OPTION_AUTOROTATEPAGES_NONE:
+                    gsArgs.add("-dAutoRotatePages=/None");
+                    break;
+                case OPTION_AUTOROTATEPAGES_ALL:
+                    gsArgs.add("-dAutoRotatePages=/All");
+                    break;
+                case OPTION_AUTOROTATEPAGES_PAGEBYPAGE:
+                    gsArgs.add("-dAutoRotatePages=/PageByPage");
+                    break;
+                default:
+                    break;
+            }
+            switch (processColorModel) {
+                case OPTION_PROCESSCOLORMODEL_CMYK:
+                    gsArgs.add("-dProcessColorModel=/DeviceCMYK");
+                    break;
+                case OPTION_PROCESSCOLORMODEL_GRAY:
+                    gsArgs.add("-dProcessColorModel=/DeviceGray");
+                    break;
+                default:
+                    gsArgs.add("-dProcessColorModel=/DeviceRGB");
+                    break;
+            }
+            switch (pdfsettings) {
+                case OPTION_PDFSETTINGS_EBOOK:
+                    gsArgs.add("-dPDFSETTINGS=/ebook");
+                    break;
+                case OPTION_PDFSETTINGS_SCREEN:
+                    gsArgs.add("-dPDFSETTINGS=/screen");
+                    break;
+                case OPTION_PDFSETTINGS_PRINTER:
+                    gsArgs.add("-dPDFSETTINGS=/printer");
+                    break;
+                case OPTION_PDFSETTINGS_PREPRESS:
+                    gsArgs.add("-dPDFSETTINGS=/prepress");
+                    break;
+                default:
+                    gsArgs.add("-dPDFSETTINGS=/default");
+                    break;
+            }
+            gsArgs.add("-dCompatibilityLevel=" + compatibilityLevel);
+            gsArgs.add("-dPDFX=" + pdfx);
+            gsArgs.add("-dDEVICEWIDTHPOINTS=" + paperSize.getWidth());
+            gsArgs.add("-dDEVICEHEIGHTPOINTS=" + paperSize.getHeight());
+            gsArgs.add("-sDEVICE=pdfwrite");
+            gsArgs.add("-sOutputFile=" + output.toAbsolutePath().toString());
+            //gsArgs.add("-q");
+            gsArgs.add("-f");
+            gsArgs.add("-");
+            try {
+                gs.setStdIn(inputStream);
+                gs.setStdOut(new LoggingOutputStream(logger));
+                gs.setStdErr(new LoggingOutputStream(logger));
+                gs.run(gsArgs.toArray(new String[gsArgs.size()]));
+                Files.copy(output.toAbsolutePath(), outputStream);
+            } finally {
+                delete(tmpPath);
+            }
         } finally {
-            delete(tmpPath);
+            gs.close();
         }
     }
 
diff --git a/graphics-ghostscript/src/main/java/org/xbib/graphics/ghostscript/PDFRasterizer.java b/graphics-ghostscript/src/main/java/org/xbib/graphics/ghostscript/PDFRasterizer.java
index 891162e..75de4e6 100644
--- a/graphics-ghostscript/src/main/java/org/xbib/graphics/ghostscript/PDFRasterizer.java
+++ b/graphics-ghostscript/src/main/java/org/xbib/graphics/ghostscript/PDFRasterizer.java
@@ -143,11 +143,15 @@ public class PDFRasterizer {
         logger.info("pdfToImage args=" + gsArgs);
         // reset stdin
         Ghostscript gs = Ghostscript.getInstance();
-        gs.setStdIn(null);
-        gs.setStdOut(new LoggingOutputStream(logger));
-        gs.setStdErr(new LoggingOutputStream(logger));
-        gs.run(gsArgs.toArray(new String[gsArgs.size()]));
-        logger.info("pdfToImage done");
+        try {
+            gs.setStdIn(null);
+            gs.setStdOut(new LoggingOutputStream(logger));
+            gs.setStdErr(new LoggingOutputStream(logger));
+            gs.run(gsArgs.toArray(new String[gsArgs.size()]));
+            logger.info("pdfToImage done");
+        } finally {
+            gs.close();
+        }
     }
 
     public synchronized void pdfToImage(Path sourceFile,
@@ -179,12 +183,16 @@ public class PDFRasterizer {
         gsArgs.add(sourceFile.toString());
         logger.info("pdfToImage args=" + gsArgs);
         Ghostscript gs = Ghostscript.getInstance();
-        // reset stdin
-        gs.setStdIn(null);
-        gs.setStdOut(new LoggingOutputStream(logger));
-        gs.setStdErr(new LoggingOutputStream(logger));
-        gs.run(gsArgs.toArray(new String[gsArgs.size()]));
-        logger.info("pdfToImage done");
+        try {
+            // reset stdin
+            gs.setStdIn(null);
+            gs.setStdOut(new LoggingOutputStream(logger));
+            gs.setStdErr(new LoggingOutputStream(logger));
+            gs.run(gsArgs.toArray(new String[gsArgs.size()]));
+            logger.info("pdfToImage done");
+        } finally {
+            gs.close();
+        }
     }
 
     public int mergeImagesToPDF(Path sourceDir, Path targetFile) throws IOException {
@@ -287,10 +295,14 @@ public class PDFRasterizer {
         gsArgs.add("-sOutputFile=" + targetFile.toString());
         gsArgs.add(sourceFile.toString());
         Ghostscript gs = Ghostscript.getInstance();
-        gs.setStdIn(null);
-        logger.info(gsArgs.toString());
-        gs.run(gsArgs.toArray(new String[gsArgs.size()]));
-        logger.info("scalePDF: source = " + sourceFile + " target = " + targetFile + " done");
+        try {
+            gs.setStdIn(null);
+            logger.info(gsArgs.toString());
+            gs.run(gsArgs.toArray(new String[gsArgs.size()]));
+            logger.info("scalePDF: source = " + sourceFile + " target = " + targetFile + " done");
+        } finally {
+            gs.close();
+        }
     }
 
     public void toPDFA(Path source, Path target) throws IOException {
@@ -326,14 +338,15 @@ public class PDFRasterizer {
         gsArgs.add("-sOutputFile=" + target.toString());
         gsArgs.add(pdfapsPath.toAbsolutePath().toString());
         gsArgs.add(source.toString());
+        Ghostscript gs = Ghostscript.getInstance();
         try {
-            Ghostscript gs = Ghostscript.getInstance();
             gs.setStdIn(null);
             gs.run(gsArgs.toArray(new String[gsArgs.size()]));
         } finally {
             delete(pdfapsPathTmp);
             delete(pdfapsPath);
             delete(iccPath);
+            gs.close();
         }
     }
 
diff --git a/graphics-ghostscript/src/main/java/org/xbib/graphics/ghostscript/GhostScriptLibraryTester.java b/graphics-ghostscript/src/test/java/org/xbib/graphics/ghostscript/test/GhostScriptLibraryTester.java
similarity index 99%
rename from graphics-ghostscript/src/main/java/org/xbib/graphics/ghostscript/GhostScriptLibraryTester.java
rename to graphics-ghostscript/src/test/java/org/xbib/graphics/ghostscript/test/GhostScriptLibraryTester.java
index c39000f..8a41cc8 100644
--- a/graphics-ghostscript/src/main/java/org/xbib/graphics/ghostscript/GhostScriptLibraryTester.java
+++ b/graphics-ghostscript/src/test/java/org/xbib/graphics/ghostscript/test/GhostScriptLibraryTester.java
@@ -1,4 +1,4 @@
-package org.xbib.graphics.ghostscript;
+package org.xbib.graphics.ghostscript.test;
 
 import com.sun.jna.ptr.IntByReference;
 import org.xbib.graphics.ghostscript.internal.GhostscriptLibrary;
diff --git a/graphics-ghostscript/src/test/java/org/xbib/graphics/ghostscript/test/GhostscriptLibraryTest.java b/graphics-ghostscript/src/test/java/org/xbib/graphics/ghostscript/test/GhostscriptLibraryTest.java
index 12b7fe0..cb0c06b 100644
--- a/graphics-ghostscript/src/test/java/org/xbib/graphics/ghostscript/test/GhostscriptLibraryTest.java
+++ b/graphics-ghostscript/src/test/java/org/xbib/graphics/ghostscript/test/GhostscriptLibraryTest.java
@@ -3,7 +3,6 @@ package org.xbib.graphics.ghostscript.test;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
-import org.xbib.graphics.ghostscript.GhostScriptLibraryTester;
 
 import java.io.File;
 import java.util.logging.Logger;
diff --git a/graphics-ghostscript/src/test/java/org/xbib/graphics/ghostscript/test/GhostscriptTest.java b/graphics-ghostscript/src/test/java/org/xbib/graphics/ghostscript/test/GhostscriptTest.java
index a7f478f..05223a0 100644
--- a/graphics-ghostscript/src/test/java/org/xbib/graphics/ghostscript/test/GhostscriptTest.java
+++ b/graphics-ghostscript/src/test/java/org/xbib/graphics/ghostscript/test/GhostscriptTest.java
@@ -1,5 +1,8 @@
 package org.xbib.graphics.ghostscript.test;
 
+import java.io.IOException;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 import org.xbib.graphics.ghostscript.Ghostscript;
@@ -20,7 +23,17 @@ public class GhostscriptTest {
 
     private static final String dir = "src/test/resources/org/xbib/graphics/ghostscript/test/";
 
-    private static final Ghostscript gs = Ghostscript.getInstance();
+    static Ghostscript gs;
+
+    @BeforeAll
+    public static void init() {
+        gs = Ghostscript.getInstance();
+    }
+
+    @AfterAll
+    public static void shutdown() throws IOException {
+        gs.close();
+    }
 
     @Test
     public void testGetRevision() {