diff --git a/rtengine/EdgePreservingDecomposition.cc b/rtengine/EdgePreservingDecomposition.cc
index 85b7ce243..85770826e 100644
--- a/rtengine/EdgePreservingDecomposition.cc
+++ b/rtengine/EdgePreservingDecomposition.cc
@@ -5,7 +5,6 @@
 #include <omp.h>
 #endif
 #include "sleef.c"
-#include "opthelper.h"
 
 #define DIAGONALS 5
 #define DIAGONALSP1 6
diff --git a/rtengine/LUT.h b/rtengine/LUT.h
index d1ed67c2b..a80e5996d 100644
--- a/rtengine/LUT.h
+++ b/rtengine/LUT.h
@@ -66,7 +66,6 @@
 #include <fstream>
 #endif
 
-#include "noncopyable.h"
 #include "opthelper.h"
 #include "rt_math.h"
 
diff --git a/rtengine/dcp.cc b/rtengine/dcp.cc
index f15ae902f..d3ab1b3f1 100644
--- a/rtengine/dcp.cc
+++ b/rtengine/dcp.cc
@@ -34,6 +34,7 @@
 #include "rawimagesource.h"
 #include "rt_math.h"
 #include "utils.h"
+#include "../rtexif/rtexif.h"
 #include "../rtgui/options.h"
 
 using namespace rtengine;
diff --git a/rtengine/imagedata.cc b/rtengine/imagedata.cc
index d952dc8ba..24cfefde9 100644
--- a/rtengine/imagedata.cc
+++ b/rtengine/imagedata.cc
@@ -32,6 +32,7 @@
 #include "procparams.h"
 #include "rt_math.h"
 #include "utils.h"
+#include "../rtexif/rtexif.h"
 
 #pragma GCC diagnostic warning "-Wextra"
 #define PRINT_HDR_PS_DETECTION 0
diff --git a/rtengine/imagedata.h b/rtengine/imagedata.h
index 0b75e263b..ff8ed4b86 100644
--- a/rtengine/imagedata.h
+++ b/rtengine/imagedata.h
@@ -29,7 +29,11 @@
 
 #include "imageio.h"
 
-#include "../rtexif/rtexif.h"
+namespace rtexif
+{
+
+class TagDirectory;
+}
 
 namespace rtengine
 {
diff --git a/rtengine/imageio.cc b/rtengine/imageio.cc
index 5927a23be..fce181c3f 100644
--- a/rtengine/imageio.cc
+++ b/rtengine/imageio.cc
@@ -30,6 +30,7 @@
 #include "utils.h"
 #include "../rtgui/options.h"
 #include "../rtgui/version.h"
+#include "../rtexif/rtexif.h"
 
 #ifdef WIN32
 #include <winsock2.h>
diff --git a/rtengine/imageio.h b/rtengine/imageio.h
index 251187547..d9afa926f 100644
--- a/rtengine/imageio.h
+++ b/rtengine/imageio.h
@@ -29,8 +29,6 @@
 #include "imageformat.h"
 #include "rtengine.h"
 
-#include "../rtexif/rtexif.h"
-
 enum {
     IMIO_SUCCESS,
     IMIO_CANNOTREADFILE,
@@ -42,6 +40,13 @@ enum {
     IMIO_CANNOTWRITEFILE
 };
 
+namespace rtexif
+{
+
+class TagDirectory;
+
+}
+
 namespace rtengine
 {
 
@@ -49,6 +54,13 @@ class ColorTemp;
 class ProgressListener;
 class Imagefloat;
 
+namespace procparams
+{
+
+class ExifPairs;
+
+}
+
 class ImageIO : virtual public ImageDatas
 {
 
diff --git a/rtengine/improccoordinator.cc b/rtengine/improccoordinator.cc
index d5242f4df..bed101e0d 100644
--- a/rtengine/improccoordinator.cc
+++ b/rtengine/improccoordinator.cc
@@ -33,6 +33,7 @@
 #include "imagefloat.h"
 #include "improcfun.h"
 #include "labimage.h"
+#include "lcp.h"
 #include "procparams.h"
 #include "refreshmap.h"
 
diff --git a/rtengine/improcfun.h b/rtengine/improcfun.h
index a8c3ededb..2c4efbfe9 100644
--- a/rtengine/improcfun.h
+++ b/rtengine/improcfun.h
@@ -18,17 +18,17 @@
  */
 #pragma once
 
+#include <memory>
+
 #include "color.h"
 #include "coord2d.h"
 #include "gamutwarning.h"
-#include "lcp.h"
 #include "LUT.h"
 #include "pipettebuffer.h"
 #include "shmap.h"
 
 template<typename T, const size_t num>
 class multi_array2D;
-
 namespace rtengine
 {
 
@@ -38,6 +38,7 @@ class DCPProfile;
 class DCPProfileApplyState;
 class FlatCurve;
 class FramesMetaData;
+class LensCorrection;
 class NoiseCurve;
 class OpacityCurve;
 class ToneCurve;
diff --git a/rtengine/lcp.cc b/rtengine/lcp.cc
index b42950eb4..57a87c1f1 100644
--- a/rtengine/lcp.cc
+++ b/rtengine/lcp.cc
@@ -32,6 +32,7 @@
 
 #include "lcp.h"
 
+#include "opthelper.h"
 #include "procparams.h"
 #include "rt_math.h"
 #include "settings.h"
diff --git a/rtengine/lcp.h b/rtengine/lcp.h
index 60df289e8..69fd43932 100644
--- a/rtengine/lcp.h
+++ b/rtengine/lcp.h
@@ -29,7 +29,6 @@
 #include <expat.h>
 
 #include "cache.h"
-#include "opthelper.h"
 
 namespace rtengine
 {
diff --git a/rtengine/rtengine.h b/rtengine/rtengine.h
index d1300f023..287759009 100644
--- a/rtengine/rtengine.h
+++ b/rtengine/rtengine.h
@@ -21,6 +21,7 @@
 #include <array>
 #include <ctime>
 #include <string>
+#include <memory>
 
 #include <glibmm/ustring.h>
 
@@ -34,8 +35,6 @@
 #include "rt_math.h"
 #include "settings.h"
 
-#include "../rtexif/rtexif.h"
-
 #include "../rtgui/threadutils.h"
 
 /**
@@ -45,6 +44,12 @@
  */
 
 class EditDataProvider;
+namespace rtexif
+{
+
+class TagDirectory;
+
+}
 
 namespace rtengine
 {
diff --git a/rtgui/exifpanel.h b/rtgui/exifpanel.h
index 2b173c884..0894c21ad 100644
--- a/rtgui/exifpanel.h
+++ b/rtgui/exifpanel.h
@@ -23,6 +23,7 @@
 #include <gtkmm.h>
 
 #include "toolpanel.h"
+#include "../rtexif/rtexif.h"
 
 class ExifPanel :
     public Gtk::VBox,
diff --git a/rtgui/resize.cc b/rtgui/resize.cc
index 456b924ef..a65875426 100644
--- a/rtgui/resize.cc
+++ b/rtgui/resize.cc
@@ -16,6 +16,9 @@
  *  You should have received a copy of the GNU General Public License
  *  along with RawTherapee.  If not, see <https://www.gnu.org/licenses/>.
  */
+
+#include <iomanip>
+
 #include "resize.h"
 
 #include "eventmapper.h"
diff --git a/rtgui/thumbnail.cc b/rtgui/thumbnail.cc
index d5038bba5..cd7470263 100644
--- a/rtgui/thumbnail.cc
+++ b/rtgui/thumbnail.cc
@@ -35,6 +35,7 @@
 #include "../rtengine/dynamicprofile.h"
 #include "../rtengine/profilestore.h"
 #include "../rtengine/settings.h"
+#include "../rtexif/rtexif.h"
 #include "guiutils.h"
 #include "batchqueue.h"
 #include "extprog.h"
diff --git a/rtgui/toolpanelcoord.cc b/rtgui/toolpanelcoord.cc
index 1da43f6c0..e774e3d39 100644
--- a/rtgui/toolpanelcoord.cc
+++ b/rtgui/toolpanelcoord.cc
@@ -18,6 +18,7 @@
  */
 #include "multilangmgr.h"
 #include "toolpanelcoord.h"
+#include "metadatapanel.h"
 #include "options.h"
 #include "rtimage.h"
 #include "../rtengine/imagesource.h"
diff --git a/rtgui/toolpanelcoord.h b/rtgui/toolpanelcoord.h
index 7b6e23937..4313f6d12 100644
--- a/rtgui/toolpanelcoord.h
+++ b/rtgui/toolpanelcoord.h
@@ -54,7 +54,6 @@
 #include "lensgeomlistener.h"
 #include "lensprofile.h"
 #include "localcontrast.h"
-#include "metadatapanel.h"
 #include "pcvignette.h"
 #include "pdsharpening.h"
 #include "perspective.h"
@@ -89,6 +88,7 @@
 #include "../rtengine/rtengine.h"
 
 class ImageEditorCoordinator;
+class MetaDataPanel;
 
 class ToolPanelCoordinator :
     public ToolPanelListener,