diff --git a/toonz/sources/colorfx/colorfxutils.h b/toonz/sources/colorfx/colorfxutils.h
index eeff9b0..14790d5 100644
--- a/toonz/sources/colorfx/colorfxutils.h
+++ b/toonz/sources/colorfx/colorfxutils.h
@@ -8,15 +8,14 @@
 #include "trandom.h"
 #include "tregionoutline.h"
 #include "tcurves.h"
-using namespace std;
 
 class TRegion;
 class TFlash;
 
 class RubberDeform
 {
-	vector<T3DPointD> *m_pPolyOri;
-	vector<T3DPointD> m_polyLoc;
+	std::vector<T3DPointD> *m_pPolyOri;
+	std::vector<T3DPointD> m_polyLoc;
 
 	void deformStep();
 	double avgLength();
@@ -25,7 +24,7 @@ class RubberDeform
 
 public:
 	RubberDeform();
-	RubberDeform(vector<T3DPointD> *pPolyOri, const double rf = -1.0);
+	RubberDeform(std::vector<T3DPointD> *pPolyOri, const double rf = -1.0);
 	void copyLoc2Ori() { *m_pPolyOri = m_polyLoc; };
 	void copyOri2Loc() { m_polyLoc = *m_pPolyOri; };
 
@@ -36,12 +35,12 @@ public:
 class SFlashUtils
 {
 	void computeOutline(const TRegion *region, TRegionOutline::PointVector &polyline) const;
-	void PointVector2QuadsArray(const vector<T3DPointD> &pv,
-								vector<TQuadratic *> &quadArray,
-								vector<TQuadratic *> &toBeDeleted,
+	void PointVector2QuadsArray(const std::vector<T3DPointD> &pv,
+								std::vector<TQuadratic *> &quadArray,
+								std::vector<TQuadratic *> &toBeDeleted,
 								const bool isRounded) const;
-	int nbDiffVerts(const vector<TPointD> &pv) const;
-	void Triangle2Quad(vector<TPointD> &p) const;
+	int nbDiffVerts(const std::vector<TPointD> &pv) const;
+	void Triangle2Quad(std::vector<TPointD> &p) const;
 
 public:
 	const TRegion *m_r;
@@ -54,11 +53,11 @@ public:
 	void computeRegionOutline();
 	void drawRegionOutline(TFlash &flash, const bool isRounded = true) const;
 	void drawGradedPolyline(TFlash &flash,
-							vector<TPointD> &pv,
+							std::vector<TPointD> &pv,
 							const TPixel32 &c1,
 							const TPixel32 &c2) const;
 	void drawGradedRegion(TFlash &flash,
-						  vector<TPointD> &pv,
+						  std::vector<TPointD> &pv,
 						  const TPixel32 &c1,
 						  const TPixel32 &c2,
 						  const TRegion &r) const;
diff --git a/toonz/sources/common/psdlib/psd.h b/toonz/sources/common/psdlib/psd.h
index e243116..1538cbe 100644
--- a/toonz/sources/common/psdlib/psd.h
+++ b/toonz/sources/common/psdlib/psd.h
@@ -7,7 +7,6 @@
 #include "timage_io.h"
 
 #define REF_LAYER_BY_NAME
-using namespace std;
 
 class TRasterImageP;
 
diff --git a/toonz/sources/common/tvectorimage/tvectorimage.cpp b/toonz/sources/common/tvectorimage/tvectorimage.cpp
index f9289aa..07fdbf2 100644
--- a/toonz/sources/common/tvectorimage/tvectorimage.cpp
+++ b/toonz/sources/common/tvectorimage/tvectorimage.cpp
@@ -1662,7 +1662,7 @@ bool TVectorImage::isStrokeStyleEnabled(int index)
 
 //-----------------------------------------------------------------------------
 
-void TVectorImage::getUsedStyles(set<int> &styles) const
+void TVectorImage::getUsedStyles(std::set<int> &styles) const
 {
 	UINT strokeCount = getStrokeCount();
 	UINT i = 0;
@@ -2856,7 +2856,7 @@ bool TVectorImage::Imp::canMoveStrokes(int strokeIndex, int count, int moveBefor
 
 	int i, j = 0;
 
-	vector<TGroupId> groupsAfterMoving(m_strokes.size());
+	std::vector<TGroupId> groupsAfterMoving(m_strokes.size());
 	if (strokeIndex < moveBefore) {
 		for (i = 0; i < strokeIndex; i++)
 			groupsAfterMoving[j++] = m_strokes[i]->m_groupId;
@@ -2887,7 +2887,7 @@ bool TVectorImage::Imp::canMoveStrokes(int strokeIndex, int count, int moveBefor
 
 	i = 0;
 	TGroupId currGroupId;
-	set<TGroupId> groupSet;
+	std::set<TGroupId> groupSet;
 
 	while (i < (int)groupsAfterMoving.size()) {
 		currGroupId = groupsAfterMoving[i];
@@ -2907,11 +2907,11 @@ bool TVectorImage::Imp::canMoveStrokes(int strokeIndex, int count, int moveBefor
 
 //-----------------------------------------------------------------
 
-void TVectorImage::Imp::regroupGhosts(vector<int> &changedStrokes)
+void TVectorImage::Imp::regroupGhosts(std::vector<int> &changedStrokes)
 {
 	TGroupId currGroupId;
-	set<TGroupId> groupMap;
-	set<TGroupId>::iterator it;
+	std::set<TGroupId> groupMap;
+	std::set<TGroupId>::iterator it;
 	UINT i = 0;
 
 	while (i < m_strokes.size()) {
diff --git a/toonz/sources/common/tvectorimage/tvectorimageP.h b/toonz/sources/common/tvectorimage/tvectorimageP.h
index 3d20654..a1b2a9a 100644
--- a/toonz/sources/common/tvectorimage/tvectorimageP.h
+++ b/toonz/sources/common/tvectorimage/tvectorimageP.h
@@ -7,7 +7,6 @@
 #include "tvectorimage.h"
 #include "tregion.h"
 #include "tcurves.h"
-using namespace std;
 
 //-----------------------------------------------------------------------------
 
diff --git a/toonz/sources/image/psd/tiio_psd.cpp b/toonz/sources/image/psd/tiio_psd.cpp
index a3b962b..e091604 100644
--- a/toonz/sources/image/psd/tiio_psd.cpp
+++ b/toonz/sources/image/psd/tiio_psd.cpp
@@ -78,7 +78,7 @@ TLevelP TLevelReaderPsd::loadInfo()
 	m_frameTable.clear();
 	for (int i = 0; i < framesCount; i++) {
 		TFrameId frame(i + 1);
-		m_frameTable.insert(make_pair(frame, psdparser->getFrameId(m_layerId, i)));
+		m_frameTable.insert(std::make_pair(frame, psdparser->getFrameId(m_layerId, i)));
 		level->setFrame(frame, TImageP());
 	}
 	return level;
diff --git a/toonz/sources/include/tcommon.h b/toonz/sources/include/tcommon.h
index 134430f..b55efa0 100644
--- a/toonz/sources/include/tcommon.h
+++ b/toonz/sources/include/tcommon.h
@@ -277,7 +277,7 @@ inline TINT32 swapTINT32(TINT32 val)
 }
 inline USHORT swapUshort(USHORT val) { return val >> 8 | val << 8; }
 
-inline ostream &operator<<(ostream &out, const string &s)
+inline std::ostream &operator<<(std::ostream &out, const std::string &s)
 {
 	return out << s.c_str();
 }
diff --git a/toonz/sources/include/tcontenthistory.h b/toonz/sources/include/tcontenthistory.h
index a563279..ce882e2 100644
--- a/toonz/sources/include/tcontenthistory.h
+++ b/toonz/sources/include/tcontenthistory.h
@@ -10,7 +10,6 @@
 #include <map>
 #include <set>
 
-using namespace std;
 #undef DVAPI
 #undef DVVAR
 #ifdef TNZCORE_EXPORTS
diff --git a/toonz/sources/include/tconvert.h b/toonz/sources/include/tconvert.h
index c496867..dc9344a 100644
--- a/toonz/sources/include/tconvert.h
+++ b/toonz/sources/include/tconvert.h
@@ -18,31 +18,31 @@ class TFilePath;
 #define DVAPI DV_IMPORT_API
 #endif
 
-DVAPI bool isInt(string s);
-DVAPI bool isDouble(string s);
+DVAPI bool isInt(std::string s);
+DVAPI bool isDouble(std::string s);
 
-DVAPI string toString(int v);
-DVAPI string toString(unsigned long v);
-DVAPI string toString(unsigned long long v);
-DVAPI string toString(double v, int prec = -1);
-DVAPI string toString(wstring s);
-DVAPI string toString(const TFilePath &fp);
-DVAPI string toString(void *p);
+DVAPI std::string toString(int v);
+DVAPI std::string toString(unsigned long v);
+DVAPI std::string toString(unsigned long long v);
+DVAPI std::string toString(double v, int prec = -1);
+DVAPI std::string toString(wstring s);
+DVAPI std::string toString(const TFilePath &fp);
+DVAPI std::string toString(void *p);
 
-DVAPI int toInt(string s);
-DVAPI double toDouble(string s);
+DVAPI int toInt(std::string s);
+DVAPI double toDouble(std::string s);
 
-DVAPI bool isInt(wstring s);
-DVAPI bool isDouble(wstring s);
+DVAPI bool isInt(std::wstring s);
+DVAPI bool isDouble(std::wstring s);
 
-DVAPI wstring toWideString(string s);
-DVAPI wstring toWideString(int v);
-DVAPI wstring toWideString(double v, int prec = -1);
+DVAPI std::wstring toWideString(std::string s);
+DVAPI std::wstring toWideString(int v);
+DVAPI std::wstring toWideString(double v, int prec = -1);
 
-DVAPI int toInt(wstring s);
-DVAPI double toDouble(wstring s);
+DVAPI int toInt(std::wstring s);
+DVAPI double toDouble(std::wstring s);
 
-inline bool fromStr(int &v, string s)
+inline bool fromStr(int &v, std::string s)
 {
 	if (isInt(s)) {
 		v = toInt(s);
@@ -51,7 +51,7 @@ inline bool fromStr(int &v, string s)
 		return false;
 }
 
-inline bool fromStr(double &v, string s)
+inline bool fromStr(double &v, std::string s)
 {
 	if (isDouble(s)) {
 		v = toDouble(s);
@@ -60,17 +60,17 @@ inline bool fromStr(double &v, string s)
 		return false;
 }
 
-inline bool fromStr(string &out, string s)
+inline bool fromStr(std::string &out, std::string s)
 {
 	out = s;
 	return true;
 }
 
-DVAPI string toUpper(string a);
-DVAPI string toLower(string a);
+DVAPI std::string toUpper(std::string a);
+DVAPI std::string toLower(std::string a);
 
-DVAPI wstring toUpper(wstring a);
-DVAPI wstring toLower(wstring a);
+DVAPI std::wstring toUpper(std::wstring a);
+DVAPI std::wstring toLower(std::wstring a);
 
 #ifndef TNZCORE_LIGHT
 #include <QString>
diff --git a/toonz/sources/include/tools/toolutils.h b/toonz/sources/include/tools/toolutils.h
index 7a30272..cab1634 100644
--- a/toonz/sources/include/tools/toolutils.h
+++ b/toonz/sources/include/tools/toolutils.h
@@ -37,8 +37,6 @@
 #define DVVAR DV_IMPORT_VAR
 #endif
 
-using namespace std;
-
 //===================================================================
 
 //    Forward declarations
diff --git a/toonz/sources/tnztools/cuttertool.cpp b/toonz/sources/tnztools/cuttertool.cpp
index 336ed44..7402d29 100644
--- a/toonz/sources/tnztools/cuttertool.cpp
+++ b/toonz/sources/tnztools/cuttertool.cpp
@@ -253,21 +253,21 @@ public:
 				w = strokeRef->getParameterAtLength(len);
 			}
 
-			vector<DoublePair> *sortedWRanges = new vector<DoublePair>;
+			std::vector<DoublePair> *sortedWRanges = new std::vector<DoublePair>;
 
 			if (strokeRef->isSelfLoop()) {
-				sortedWRanges->push_back(make_pair(0, w));
-				sortedWRanges->push_back(make_pair(w, 1));
+				sortedWRanges->push_back(std::make_pair(0, w));
+				sortedWRanges->push_back(std::make_pair(w, 1));
 			} else {
 				if (w == 0 || w == 1)
-					sortedWRanges->push_back(make_pair(0, 1));
+					sortedWRanges->push_back(std::make_pair(0, 1));
 				else {
-					sortedWRanges->push_back(make_pair(0, w));
-					sortedWRanges->push_back(make_pair(w, 1));
+					sortedWRanges->push_back(std::make_pair(0, w));
+					sortedWRanges->push_back(std::make_pair(w, 1));
 				}
 			}
 
-			vector<TFilledRegionInf> *fillInformation = new vector<TFilledRegionInf>;
+			std::vector<TFilledRegionInf> *fillInformation = new std::vector<TFilledRegionInf>;
 			ImageUtils::getFillingInformationOverlappingArea(vi, *fillInformation, strokeRef->getBBox());
 
 			VIStroke *oldStroke = cloneVIStroke(vi->getVIStroke(strokeIndex));
diff --git a/toonz/sources/tnztools/vectorerasertool.cpp b/toonz/sources/tnztools/vectorerasertool.cpp
index 3d790e3..03025e2 100644
--- a/toonz/sources/tnztools/vectorerasertool.cpp
+++ b/toonz/sources/tnztools/vectorerasertool.cpp
@@ -709,7 +709,7 @@ void EraserTool::erase(TVectorImageP vi, const TPointD &pos)
 		sortedWRanges.reserve(intersections.size() / 2);
 
 		for (UINT j = 0; j < intersections.size() - 1; j += 2)
-			sortedWRanges.push_back(make_pair(intersections[j], intersections[j + 1]));
+			sortedWRanges.push_back(std::make_pair(intersections[j], intersections[j + 1]));
 
 #ifdef _DEBUG
 
diff --git a/toonz/sources/tnztools/vectorselectiontool.cpp b/toonz/sources/tnztools/vectorselectiontool.cpp
index fdecbd7..140d233 100644
--- a/toonz/sources/tnztools/vectorselectiontool.cpp
+++ b/toonz/sources/tnztools/vectorselectiontool.cpp
@@ -128,12 +128,12 @@ inline void notifySelectionChanged()
 //    VectorFreeDeformer  implementation
 //********************************************************************************
 
-VectorFreeDeformer::VectorFreeDeformer(TVectorImageP vi, set<int> strokeIndexes)
+VectorFreeDeformer::VectorFreeDeformer(TVectorImageP vi, std::set<int> strokeIndexes)
 	: FreeDeformer(), m_vi(vi), m_strokeIndexes(strokeIndexes), m_preserveThickness(false), m_computeRegion(false), m_flip(false)
 {
 	TRectD r;
 
-	set<int>::iterator it, iEnd = m_strokeIndexes.end();
+	std::set<int>::iterator it, iEnd = m_strokeIndexes.end();
 	for (it = m_strokeIndexes.begin(); it != iEnd; ++it) {
 		TStroke *stroke = m_vi->getStroke(*it);
 		r += stroke->getBBox();
diff --git a/toonz/sources/tnztools/vectorselectiontool.h b/toonz/sources/tnztools/vectorselectiontool.h
index 32a93ea..7f40c24 100644
--- a/toonz/sources/tnztools/vectorselectiontool.h
+++ b/toonz/sources/tnztools/vectorselectiontool.h
@@ -68,15 +68,15 @@ enum SelectionTarget //! Possible selection targets in a SelectionTool.
 class VectorFreeDeformer : public FreeDeformer
 {
 	TVectorImageP m_vi;
-	set<int> m_strokeIndexes;
-	vector<TStroke *> m_originalStrokes;
+	std::set<int> m_strokeIndexes;
+	std::vector<TStroke *> m_originalStrokes;
 
 	bool m_preserveThickness, m_computeRegion, m_flip;
 
 	TThickPoint deform(TThickPoint point);
 
 public:
-	VectorFreeDeformer(TVectorImageP vi, set<int> strokeIndexes);
+	VectorFreeDeformer(TVectorImageP vi, std::set<int> strokeIndexes);
 	~VectorFreeDeformer();
 
 	void setPreserveThickness(bool preserveThickness);
diff --git a/toonz/sources/toonz/insertfxpopup.h b/toonz/sources/toonz/insertfxpopup.h
index fe79d69..70f4718 100644
--- a/toonz/sources/toonz/insertfxpopup.h
+++ b/toonz/sources/toonz/insertfxpopup.h
@@ -15,7 +15,6 @@ class TFx;
 #include <QIcon>
 
 using namespace DVGui;
-using namespace std;
 
 //=============================================================================
 // InsertFxPopup
diff --git a/toonz/sources/toonz/linesfadepopup.h b/toonz/sources/toonz/linesfadepopup.h
index be2cc55..a4ad44a 100644
--- a/toonz/sources/toonz/linesfadepopup.h
+++ b/toonz/sources/toonz/linesfadepopup.h
@@ -7,8 +7,6 @@
 #include "toonz/txshsimplelevel.h"
 #include "traster.h"
 
-using namespace std;
-
 class QSlider;
 class ImageViewer;
 class TSelection;
diff --git a/toonz/sources/toonz/matchline.cpp b/toonz/sources/toonz/matchline.cpp
index 796d188..ae67dc7 100644
--- a/toonz/sources/toonz/matchline.cpp
+++ b/toonz/sources/toonz/matchline.cpp
@@ -875,19 +875,19 @@ bool contains(const vector<TFrameId> &v, const TFrameId &val)
 
 //-----------------------------------------------------------------------------
 
-QString indexes2string(const set<TFrameId> fids)
+QString indexes2string(const std::set<TFrameId> fids)
 {
 	if (fids.empty())
 		return "";
 
 	QString str;
 
-	set<TFrameId>::const_iterator it = fids.begin();
+	std::set<TFrameId>::const_iterator it = fids.begin();
 
 	str = QString::number(it->getNumber());
 
 	while (it != fids.end()) {
-		set<TFrameId>::const_iterator it1 = it;
+		std::set<TFrameId>::const_iterator it1 = it;
 		it1++;
 
 		int lastVal = it->getNumber();
@@ -1012,12 +1012,12 @@ void DeleteInkDialog::setRange(const QString &str)
 	 DeleteLinesコマンドから呼ばれる場合：chooseInkがtrue
 --*/
 
-void doDeleteMatchlines(TXshSimpleLevel *sl, const set<TFrameId> &fids, bool chooseInk)
+void doDeleteMatchlines(TXshSimpleLevel *sl, const std::set<TFrameId> &fids, bool chooseInk)
 {
-	vector<int> indexes;
+	std::vector<int> indexes;
 	//vector<TToonzImageP> images;
-	vector<TFrameId> frames;
-	vector<TFrameId> fidsToProcess;
+	std::vector<TFrameId> frames;
+	std::vector<TFrameId> fidsToProcess;
 	int i;
 	if (chooseInk) {
 		TPaletteHandle *ph = TApp::instance()->getPaletteController()->getCurrentLevelPalette();
@@ -1088,12 +1088,12 @@ void doDeleteMatchlines(TXshSimpleLevel *sl, const set<TFrameId> &fids, bool cho
 
 //-----------------------------------------------------------------------------
 
-void deleteMatchlines(TXshSimpleLevel *sl, const set<TFrameId> &fids)
+void deleteMatchlines(TXshSimpleLevel *sl, const std::set<TFrameId> &fids)
 {
 	doDeleteMatchlines(sl, fids, false);
 }
 
-void deleteInk(TXshSimpleLevel *sl, const set<TFrameId> &fids)
+void deleteInk(TXshSimpleLevel *sl, const std::set<TFrameId> &fids)
 {
 	doDeleteMatchlines(sl, fids, true);
 }
diff --git a/toonz/sources/toonz/mergecmapped.cpp b/toonz/sources/toonz/mergecmapped.cpp
index 7e00172..6149dd8 100644
--- a/toonz/sources/toonz/mergecmapped.cpp
+++ b/toonz/sources/toonz/mergecmapped.cpp
@@ -629,19 +629,19 @@ bool contains(const vector<TFrameId> &v, const TFrameId &val)
 
 //-----------------------------------------------------------------------------
 
-QString indexes2string(const set<TFrameId> fids)
+QString indexes2string(const std::set<TFrameId> fids)
 {
 	if (fids.empty())
 		return "";
 
 	QString str;
 
-	set<TFrameId>::const_iterator it = fids.begin();
+	std::set<TFrameId>::const_iterator it = fids.begin();
 
 	str = QString::number(it->getNumber());
 
 	while (it != fids.end()) {
-		set<TFrameId>::const_iterator it1 = it;
+		std::set<TFrameId>::const_iterator it1 = it;
 		it1++;
 
 		int lastVal = it->getNumber();
diff --git a/toonz/sources/toonz/mergecolumns.cpp b/toonz/sources/toonz/mergecolumns.cpp
index a6ac143..95f9321 100644
--- a/toonz/sources/toonz/mergecolumns.cpp
+++ b/toonz/sources/toonz/mergecolumns.cpp
@@ -260,11 +260,11 @@ public:
 
 //-----------------------------------------------------------------------------
 
-void mergeColumns(const set<int> &columns)
+void mergeColumns(const std::set<int> &columns)
 {
 	QApplication::setOverrideCursor(Qt::WaitCursor);
 
-	set<int>::const_iterator it = columns.begin();
+	std::set<int>::const_iterator it = columns.begin();
 
 	int dstColumn = *it;
 	++it;
@@ -435,19 +435,19 @@ bool contains(const vector<TFrameId> &v, const TFrameId &val)
 
 //-----------------------------------------------------------------------------
 
-QString indexes2string(const set<TFrameId> fids)
+QString indexes2string(const std::set<TFrameId> fids)
 {
 	if (fids.empty())
 		return "";
 
 	QString str;
 
-	set<TFrameId>::const_iterator it = fids.begin();
+	std::set<TFrameId>::const_iterator it = fids.begin();
 
 	str = QString::number(it->getNumber());
 
 	while (it != fids.end()) {
-		set<TFrameId>::const_iterator it1 = it;
+		std::set<TFrameId>::const_iterator it1 = it;
 		it1++;
 
 		int lastVal = it->getNumber();
diff --git a/toonz/sources/toonzfarm/include/service.h b/toonz/sources/toonzfarm/include/service.h
index 9390df2..5751836 100644
--- a/toonz/sources/toonzfarm/include/service.h
+++ b/toonz/sources/toonzfarm/include/service.h
@@ -7,7 +7,6 @@ class TFilePath;
 
 #include <string>
 #include <QString>
-using namespace std;
 
 //------------------------------------------------------------------------------
 
@@ -35,14 +34,14 @@ void AddToMessageLog(char *msg);
 
 //------------------------------------------------------------------------------
 
-TFARMAPI string getLastErrorText();
+TFARMAPI std::string getLastErrorText();
 
 //------------------------------------------------------------------------------
 
 class TFARMAPI TService
 {
 public:
-	TService(const string &name, const string &displayName);
+	TService(const std::string &name, const std::string &displayName);
 	virtual ~TService();
 
 	static TService *instance();
@@ -59,8 +58,8 @@ public:
 
 	void setStatus(Status status, long exitCode, long waitHint);
 
-	string getName() const;
-	string getDisplayName() const;
+	std::string getName() const;
+	std::string getDisplayName() const;
 
 	void run(int argc, char *argv[], bool console = false);
 
@@ -69,17 +68,17 @@ public:
 
 	bool isRunningAsConsoleApp() const;
 
-	static void start(const string &name);
-	static void stop(const string &name);
+	static void start(const std::string &name);
+	static void stop(const std::string &name);
 
 	static void install(
-		const string &name,
-		const string &displayName,
+		const std::string &name,
+		const std::string &displayName,
 		const TFilePath &appPath);
 
-	static void remove(const string &name);
+	static void remove(const std::string &name);
 
-	static void addToMessageLog(const string &msg);
+	static void addToMessageLog(const std::string &msg);
 	static void addToMessageLog(const QString &msg);
 
 private:
diff --git a/toonz/sources/toonzfarm/tfarm/service.cpp b/toonz/sources/toonzfarm/tfarm/service.cpp
index 141c551..e03e27d 100644
--- a/toonz/sources/toonzfarm/tfarm/service.cpp
+++ b/toonz/sources/toonzfarm/tfarm/service.cpp
@@ -56,9 +56,9 @@ LPTSTR GetLastErrorText(LPTSTR lpszBuf, DWORD dwSize)
 
 //------------------------------------------------------------------------------
 
-string getLastErrorText()
+std::string getLastErrorText()
 {
-	string errText;
+	std::string errText;
 #ifdef _WIN32
 	char errBuff[256];
 	errText = GetLastErrorText(errBuff, sizeof(errBuff));
@@ -89,8 +89,8 @@ public:
 
 #endif
 
-	string m_name;
-	string m_displayName;
+	std::string m_name;
+	std::string m_displayName;
 	static bool m_console;
 
 #ifdef _WIN32
@@ -111,7 +111,7 @@ bool TService::Imp::m_console = false;
 
 //------------------------------------------------------------------------------
 
-TService::TService(const string &name, const string &displayName)
+TService::TService(const std::string &name, const std::string &displayName)
 	: m_imp(new Imp)
 {
 	m_imp->m_name = name;
@@ -155,14 +155,14 @@ void TService::setStatus(Status status, long exitCode, long waitHint)
 
 //------------------------------------------------------------------------------
 
-string TService::getName() const
+std::string TService::getName() const
 {
 	return m_imp->m_name;
 }
 
 //------------------------------------------------------------------------------
 
-string TService::getDisplayName() const
+std::string TService::getDisplayName() const
 {
 	return m_imp->m_displayName;
 }
@@ -388,7 +388,7 @@ void TService::run(int argc, char *argv[], bool console)
 	} else {
 		SERVICE_TABLE_ENTRY dispatchTable[2];
 
-		string name = TService::instance()->getName().c_str();
+		std::string name = TService::instance()->getName().c_str();
 
 		dispatchTable[0].lpServiceName = (char *)name.c_str();
 		dispatchTable[0].lpServiceProc = (LPSERVICE_MAIN_FUNCTION)TService::Imp::serviceMain;
@@ -406,13 +406,13 @@ void TService::run(int argc, char *argv[], bool console)
 
 //------------------------------------------------------------------------------
 
-void TService::start(const string &name)
+void TService::start(const std::string &name)
 {
 }
 
 //------------------------------------------------------------------------------
 
-void TService::stop(const string &name)
+void TService::stop(const std::string &name)
 {
 }
 
@@ -425,7 +425,7 @@ bool TService::isRunningAsConsoleApp() const
 
 //------------------------------------------------------------------------------
 
-void TService::install(const string &name, const string &displayName, const TFilePath &appPath)
+void TService::install(const std::string &name, const std::string &displayName, const TFilePath &appPath)
 {
 #ifdef _WIN32
 	SC_HANDLE schService;
@@ -467,10 +467,10 @@ void TService::install(const string &name, const string &displayName, const TFil
 
 //------------------------------------------------------------------------------
 
-void TService::remove(const string &name)
+void TService::remove(const std::string &name)
 {
 #ifdef _WIN32
-	string displayName = name;
+	std::string displayName = name;
 
 	SC_HANDLE schService;
 	SC_HANDLE schSCManager;
@@ -529,7 +529,7 @@ void TService::addToMessageLog(const QString &msg)
 	addToMessageLog(msg.toStdString());
 }
 
-void TService::addToMessageLog(const string &msg)
+void TService::addToMessageLog(const std::string &msg)
 {
 #ifdef _WIN32
 	TCHAR szMsg[256];
@@ -561,7 +561,7 @@ void TService::addToMessageLog(const string &msg)
 			(VOID) DeregisterEventSource(hEventSource);
 		}
 	} else {
-		cout << msg.c_str();
+		std::cout << msg.c_str();
 	}
 #else
 	if (!TService::Imp::m_console) {
diff --git a/toonz/sources/toonzlib/sandor_fxs/BlurMatrix.h b/toonz/sources/toonzlib/sandor_fxs/BlurMatrix.h
index 922a646..00a4306 100644
--- a/toonz/sources/toonzlib/sandor_fxs/BlurMatrix.h
+++ b/toonz/sources/toonzlib/sandor_fxs/BlurMatrix.h
@@ -16,17 +16,15 @@
 #include "SError.h"
 #include "SDef.h"
 
-using namespace std;
-
 #define NBRS 10 //  Number of Random Samples
-typedef vector<SXYD> BLURSECTION;
+typedef std::vector<SXYD> BLURSECTION;
 
 class CBlurMatrix
 {
 public:
 	bool m_isSAC; // Stop At Contour
 	bool m_isRS;  // Random Sampling
-	vector<BLURSECTION> m_m[NBRS];
+	std::vector<BLURSECTION> m_m[NBRS];
 
 	CBlurMatrix() : m_isSAC(false), m_isRS(false){};
 	CBlurMatrix(const CBlurMatrix &m); //throw(SBlurMatrixError);
@@ -36,10 +34,10 @@ public:
 
 	void createRandom(const double d, const int nb); // throw(SBlurMatrixError);
 	void createEqual(const double d, const int nb);  // throw(SBlurMatrixError);
-	void addPath(vector<BLURSECTION>::iterator pBS); // throw(exception);
+	void addPath(std::vector<BLURSECTION>::iterator pBS); // throw(exception);
 	void addPath();									 // throw(SBlurMatrixError);
 	void print() const;
-	bool isIn(const vector<BLURSECTION> &m, const SXYD &xyd) const;
+	bool isIn(const std::vector<BLURSECTION> &m, const SXYD &xyd) const;
 };
 
 #endif // !defined(AFX_BLURMATRIX_H__8298C171_0035_11D6_B94F_0040F674BE6A__INCLUDED_)
diff --git a/toonz/sources/toonzlib/sandor_fxs/InputParam.h b/toonz/sources/toonzlib/sandor_fxs/InputParam.h
index f7d2366..3e09c15 100644
--- a/toonz/sources/toonzlib/sandor_fxs/InputParam.h
+++ b/toonz/sources/toonzlib/sandor_fxs/InputParam.h
@@ -17,14 +17,12 @@
 #include <algorithm>
 #include <string>
 
-using namespace std;
-
 class CInputParam
 {
 public:
 	double m_scale;
 	bool m_isEconf;
-	basic_string<char> m_econfFN;
+	std::basic_string<char> m_econfFN;
 
 	CInputParam() : m_scale(0), m_isEconf(false), m_econfFN(""){};
 	CInputParam(const CInputParam &p) : m_scale(p.m_scale), m_isEconf(p.m_isEconf),
diff --git a/toonz/sources/toonzlib/sandor_fxs/Params.h b/toonz/sources/toonzlib/sandor_fxs/Params.h
index 9a48740..f29680e 100644
--- a/toonz/sources/toonzlib/sandor_fxs/Params.h
+++ b/toonz/sources/toonzlib/sandor_fxs/Params.h
@@ -21,13 +21,11 @@
 
 #define P(d) tmsg_info(" - %d -\n", d)
 
-using namespace std;
-
 template <class EParam>
 class CParams
 {
 public:
-	vector<EParam> m_params;
+	std::vector<EParam> m_params;
 	double m_scale;
 
 	CParams() : m_params(0), m_scale(1.0){};
diff --git a/toonz/sources/toonzlib/sandor_fxs/PatternPosition.h b/toonz/sources/toonzlib/sandor_fxs/PatternPosition.h
index 3e75b90..e0ee507 100644
--- a/toonz/sources/toonzlib/sandor_fxs/PatternPosition.h
+++ b/toonz/sources/toonzlib/sandor_fxs/PatternPosition.h
@@ -18,8 +18,6 @@
 #include "SError.h"
 #include "SDef.h"
 
-using namespace std;
-
 class CPatternPosition
 {
 	bool isInSet(const int nbSet, const int *set, const int val);
diff --git a/toonz/sources/toonzlib/sandor_fxs/SDirection.h b/toonz/sources/toonzlib/sandor_fxs/SDirection.h
index 3da23b2..f8b1de5 100644
--- a/toonz/sources/toonzlib/sandor_fxs/SDirection.h
+++ b/toonz/sources/toonzlib/sandor_fxs/SDirection.h
@@ -17,8 +17,6 @@
 #include <array>
 #include <vector>
 
-using namespace std;
-
 //#define MSIZE 3
 
 typedef struct {
diff --git a/toonz/sources/toonzlib/sandor_fxs/SError.h b/toonz/sources/toonzlib/sandor_fxs/SError.h
index d3294b2..cdc9394 100644
--- a/toonz/sources/toonzlib/sandor_fxs/SError.h
+++ b/toonz/sources/toonzlib/sandor_fxs/SError.h
@@ -16,12 +16,10 @@
 
 #include "SDef.h"
 
-using namespace std;
-
 class SError
 {
 protected:
-	string m_msg;
+	std::string m_msg;
 
 public:
 	SError() : m_msg(""){};
diff --git a/toonz/sources/toonzlib/sandor_fxs/STColSelPic.h b/toonz/sources/toonzlib/sandor_fxs/STColSelPic.h
index 124322a..8152055 100644
--- a/toonz/sources/toonzlib/sandor_fxs/STColSelPic.h
+++ b/toonz/sources/toonzlib/sandor_fxs/STColSelPic.h
@@ -30,8 +30,6 @@
 #include "CIL.h"
 #include "SError.h"
 
-using namespace std;
-
 template <class P>
 class CSTColSelPic : public CSTPic<P>
 {
diff --git a/toonz/sources/toonzlib/sandor_fxs/YOMBParam.h b/toonz/sources/toonzlib/sandor_fxs/YOMBParam.h
index 1c92e8e..a4cd93e 100644
--- a/toonz/sources/toonzlib/sandor_fxs/YOMBParam.h
+++ b/toonz/sources/toonzlib/sandor_fxs/YOMBParam.h
@@ -22,8 +22,6 @@
 
 #define P(d) tmsg_info(" - %d -\n", d)
 
-using namespace std;
-
 class CYOMBParam
 {
 public:
@@ -81,7 +79,7 @@ public:
 	void null();
 	void read(const CInputParam &ip);
 #ifdef _WIN32
-	bool read(basic_ifstream<char> &in);
+	bool read(std::basic_ifstream<char> &in);
 #endif
 	void makeColorsUS();
 	void makeItUS();
diff --git a/toonz/sources/toonzlib/txshsimplelevel.cpp b/toonz/sources/toonzlib/txshsimplelevel.cpp
index 567097c..b031098 100644
--- a/toonz/sources/toonzlib/txshsimplelevel.cpp
+++ b/toonz/sources/toonzlib/txshsimplelevel.cpp
@@ -1489,7 +1489,7 @@ void TXshSimpleLevel::save(const TFilePath &fp, const TFilePath &oldFp, bool ove
 			sl->setPath(getScene()->codeFilePath(app));
 			sl->setType(getType());
 
-			set<TFrameId>::iterator eft, efEnd;
+			std::set<TFrameId>::iterator eft, efEnd;
 			for (eft = m_editableRange.begin(); eft != efEnd; ++eft) {
 				const TFrameId &fid = *eft;
 				sl->setFrame(fid, getFrame(fid, false));