diff --git a/Lib/ufoLib/__init__.py b/Lib/ufoLib/__init__.py
index aaa0e2893..8ee588454 100755
--- a/Lib/ufoLib/__init__.py
+++ b/Lib/ufoLib/__init__.py
@@ -151,7 +151,7 @@ class UFOReader(object):
 
 		``validate`` will validate the data.
 		"""
-		if self._upConvertedKerningData:
+		if validate and self._upConvertedKerningData:
 			testKerning = self._readKerning()
 			if testKerning != self._upConvertedKerningData["originalKerning"]:
 				raise UFOLibError("The data in kerning.plist has been modified since it was converted to UFO 3 format.")
@@ -326,9 +326,9 @@ class UFOReader(object):
 
 	# fontinfo.plist
 
-	def _readInfo(self):
+	def _readInfo(self, validate):
 		data = self._getPlist(FONTINFO_FILENAME, {})
-		if not isinstance(data, dict):
+		if validate and not isinstance(data, dict):
 			raise UFOLibError("fontinfo.plist is not properly formatted.")
 		return data
 
@@ -344,7 +344,7 @@ class UFOReader(object):
 		"""
 		if validate is None:
 			validate = self._validate
-		infoDict = self._readInfo()
+		infoDict = self._readInfo(validate)
 		infoDataToSet = {}
 		# version 1
 		if self._formatVersion == 1:
@@ -493,7 +493,8 @@ class UFOReader(object):
 			if layerDirectory == DEFAULT_GLYPHS_DIRNAME:
 				return layerName
 		# this will already have been raised during __init__
-		raise UFOLibError("The default layer is not defined in layercontents.plist.")
+		if validate:
+			raise UFOLibError("The default layer is not defined in layercontents.plist.")
 
 	def getGlyphSet(self, layerName=None, validateRead=None, validateWrite=None):
 		"""
@@ -615,10 +616,10 @@ class UFOReader(object):
 		"""
 		if validate is None:
 			validate = self._validate
-		if self._formatVersion < 3:
+		if validate and self._formatVersion < 3:
 			raise UFOLibError("Reading images is not allowed in UFO %d." % self._formatVersion)
 		data = self.readBytesFromPath(os.path.join(IMAGES_DIRNAME, fileName))
-		if data is None:
+		if validate and data is None:
 			raise UFOLibError("No image file named %s." % fileName)
 		if validate:
 			valid, error = pngValidator(data=data)
@@ -661,10 +662,10 @@ class UFOWriter(object):
 				previousFormatVersion = int(previousFormatVersion)
 			except:
 				raise UFOLibError("The existing metainfo.plist is not properly formatted.")
-			if previousFormatVersion not in supportedUFOFormatVersions:
+			if validate and previousFormatVersion not in supportedUFOFormatVersions:
 				raise UFOLibError("Unsupported UFO format (%d)." % formatVersion)
 		# catch down conversion
-		if previousFormatVersion is not None and previousFormatVersion > formatVersion:
+		if validate and previousFormatVersion is not None and previousFormatVersion > formatVersion:
 			raise UFOLibError("The UFO located at this path is a higher version (%d) than the version (%d) that is trying to be written. This is not supported." % (previousFormatVersion, formatVersion))
 		# handle the layer contents
 		self.layerContents = {}
@@ -1056,15 +1057,18 @@ class UFOWriter(object):
 
 	# features.fea
 
-	def writeFeatures(self, features):
+	def writeFeatures(self, features, validate=None):
 		"""
 		Write features.fea. This method requires a
 		features string as an argument.
 		"""
-		if self._formatVersion == 1:
-			raise UFOLibError("features.fea is not allowed in UFO Format Version 1.")
-		if not isinstance(features, basestring):
-			raise UFOLibError("The features are not text.")
+		if validate is None:
+			validate = self._validate
+		if validate:
+			if self._formatVersion == 1:
+				raise UFOLibError("features.fea is not allowed in UFO Format Version 1.")
+			if not isinstance(features, basestring):
+				raise UFOLibError("The features are not text.")
 		self._makeDirectory()
 		path = os.path.join(self._path, FEATURES_FILENAME)
 		writeFileAtomically(features, path)
@@ -1090,11 +1094,13 @@ class UFOWriter(object):
 			contents[layerName] = directoryName
 		self.layerContents = contents
 
-	def writeLayerContents(self, layerOrder=None):
+	def writeLayerContents(self, layerOrder=None, validate=None):
 		"""
 		Write the layercontents.plist file. This method  *must* be called
 		after all glyph sets have been written.
 		"""
+		if validate is None:
+			validate = self._validate
 		if self.formatVersion < 3:
 			return
 		if layerOrder is not None:
@@ -1106,7 +1112,7 @@ class UFOWriter(object):
 			layerOrder = newOrder
 		else:
 			layerOrder = list(self.layerContents.keys())
-		if set(layerOrder) != set(self.layerContents.keys()):
+		if validate and set(layerOrder) != set(self.layerContents.keys()):
 			raise UFOLibError("The layer order contents does not match the glyph sets that have been created.")
 		layerContents = [(layerName, self.layerContents[layerName]) for layerName in layerOrder]
 		self._writePlist(LAYERCONTENTS_FILENAME, layerContents)
@@ -1143,7 +1149,7 @@ class UFOWriter(object):
 		if validateWrite is None:
 			validateWrite = self._validate
 		# only default can be written in < 3
-		if self._formatVersion < 3 and (not defaultLayer or layerName is not None):
+		if validateWrite and self._formatVersion < 3 and (not defaultLayer or layerName is not None):
 			raise UFOLibError("Only the default layer can be writen in UFO %d." % self.formatVersion)
 		# locate a layer name when None has been given
 		if layerName is None and defaultLayer:
@@ -1152,7 +1158,7 @@ class UFOWriter(object):
 					layerName = existingLayerName
 			if layerName is None:
 				layerName = DEFAULT_LAYER_NAME
-		elif layerName is None and not defaultLayer:
+		elif validateWrite and layerName is None and not defaultLayer:
 			raise UFOLibError("A layer name must be provided for non-default layers.")
 		# move along to format specific writing
 		if self.formatVersion == 1:
@@ -1175,12 +1181,13 @@ class UFOWriter(object):
 		# matches the default being written. also make sure that this layer
 		# name is not already linked to a non-default layer.
 		if defaultLayer:
-			for existingLayerName, directory in list(self.layerContents.items()):
-				if directory == DEFAULT_GLYPHS_DIRNAME:
-					if existingLayerName != layerName:
-						raise UFOLibError("Another layer is already mapped to the default directory.")
-				elif existingLayerName == layerName:
-					raise UFOLibError("The layer name is already mapped to a non-default layer.")
+			if validateRead:
+				for existingLayerName, directory in list(self.layerContents.items()):
+					if directory == DEFAULT_GLYPHS_DIRNAME:
+						if existingLayerName != layerName:
+							raise UFOLibError("Another layer is already mapped to the default directory.")
+					elif existingLayerName == layerName:
+						raise UFOLibError("The layer name is already mapped to a non-default layer.")
 		# get an existing directory name
 		if layerName in self.layerContents:
 			directory = self.layerContents[layerName]
@@ -1282,24 +1289,30 @@ class UFOWriter(object):
 		path = os.path.join(IMAGES_DIRNAME, fileName)
 		self.writeBytesToPath(path, data)
 
-	def removeImage(self, fileName):
+	def removeImage(self, fileName, validate=None):
 		"""
 		Remove the file named fileName from the
 		images directory.
 		"""
-		if self._formatVersion < 3:
-			raise UFOLibError("Images are not allowed in UFO %d." % self._formatVersion)
+		if validate is None:
+			validate = self._validate
+		if validate:
+			if self._formatVersion < 3:
+				raise UFOLibError("Images are not allowed in UFO %d." % self._formatVersion)
 		path = os.path.join(IMAGES_DIRNAME, fileName)
 		self.removeFileForPath(path)
 
-	def copyImageFromReader(self, reader, sourceFileName, destFileName):
+	def copyImageFromReader(self, reader, sourceFileName, destFileName, validate=None):
 		"""
 		Copy the sourceFileName in the provided UFOReader to destFileName
 		in this writer. This uses the most memory efficient method possible
 		for copying the data possible.
 		"""
-		if self._formatVersion < 3:
-			raise UFOLibError("Images are not allowed in UFO %d." % self._formatVersion)
+		if validate is None:
+			validate = self._validate
+		if validate:
+			if self._formatVersion < 3:
+				raise UFOLibError("Images are not allowed in UFO %d." % self._formatVersion)
 		sourcePath = os.path.join("images", sourceFileName)
 		destPath = os.path.join("images", destFileName)
 		self.copyFromReader(reader, sourcePath, destPath)
diff --git a/Lib/ufoLib/glifLib.py b/Lib/ufoLib/glifLib.py
index 935077d89..c866c9cd5 100755
--- a/Lib/ufoLib/glifLib.py
+++ b/Lib/ufoLib/glifLib.py
@@ -202,9 +202,9 @@ class GlyphSet(object):
 			infoDict = self._readPlist(path)
 		except MissingPlistError:
 			return
-		if not isinstance(infoDict, dict):
-			raise GlifLibError("layerinfo.plist is not properly formatted.")
 		if validateRead:
+			if not isinstance(infoDict, dict):
+				raise GlifLibError("layerinfo.plist is not properly formatted.")
 			infoDict = validateLayerInfoVersion3Data(infoDict)
 		# populate the object
 		for attr, value in infoDict.items():
@@ -220,7 +220,7 @@ class GlyphSet(object):
 		"""
 		if validateWrite is None:
 			validateWrite = self._validateWrite
-		if self.ufoFormatVersion < 3:
+		if validateWrite and self.ufoFormatVersion < 3:
 			raise GlifLibError("layerinfo.plist is not allowed in UFO %d." % self.ufoFormatVersion)
 		# gather data
 		infoData = {}
@@ -375,7 +375,7 @@ class GlyphSet(object):
 				formatVersion = 2
 			else:
 				formatVersion = 1
-		else:
+		elif validate:
 			if formatVersion not in supportedGLIFFormatVersions:
 				raise GlifLibError("Unsupported GLIF format version: %s" % formatVersion)
 			if formatVersion == 2 and self.ufoFormatVersion < 3:
@@ -590,20 +590,20 @@ def writeGlyphToString(glyphName, glyphObject=None, drawPointsFunc=None, writer=
 		aFile = None
 	identifiers = set()
 	# start
-	if not isinstance(glyphName, basestring):
+	if validate and not isinstance(glyphName, basestring):
 		raise GlifLibError("The glyph name is not properly formatted.")
-	if len(glyphName) == 0:
+	if validate and len(glyphName) == 0:
 		raise GlifLibError("The glyph name is empty.")
 	writer.begintag("glyph", [("name", glyphName), ("format", formatVersion)])
 	writer.newline()
 	# advance
-	_writeAdvance(glyphObject, writer)
+	_writeAdvance(glyphObject, writer, validate)
 	# unicodes
 	if getattr(glyphObject, "unicodes", None):
-		_writeUnicodes(glyphObject, writer)
+		_writeUnicodes(glyphObject, writer, validate)
 	# note
 	if getattr(glyphObject, "note", None):
-		_writeNote(glyphObject, writer)
+		_writeNote(glyphObject, writer, validate)
 	# image
 	if formatVersion >= 2 and getattr(glyphObject, "image", None):
 		_writeImage(glyphObject, writer, validate)
@@ -636,16 +636,16 @@ def writeGlyphToString(glyphName, glyphObject=None, drawPointsFunc=None, writer=
 	else:
 		return None
 
-def _writeAdvance(glyphObject, writer):
+def _writeAdvance(glyphObject, writer, validate):
 	width = getattr(glyphObject, "width", None)
 	if width is not None:
-		if not isinstance(width, (int, float)):
+		if validate and not isinstance(width, (int, float)):
 			raise GlifLibError("width attribute must be int or float")
 		if width == 0:
 			width = None
 	height = getattr(glyphObject, "height", None)
 	if height is not None:
-		if not isinstance(height, (int, float)):
+		if validate and not isinstance(height, (int, float)):
 			raise GlifLibError("height attribute must be int or float")
 		if height == 0:
 			height = None
@@ -659,13 +659,13 @@ def _writeAdvance(glyphObject, writer):
 		writer.simpletag("advance", height=repr(height))
 		writer.newline()
 
-def _writeUnicodes(glyphObject, writer):
+def _writeUnicodes(glyphObject, writer, validate):
 	unicodes = getattr(glyphObject, "unicodes", None)
-	if isinstance(unicodes, int):
+	if validate and isinstance(unicodes, int):
 		unicodes = [unicodes]
 	seen = set()
 	for code in unicodes:
-		if not isinstance(code, int):
+		if validate and not isinstance(code, int):
 			raise GlifLibError("unicode values must be int")
 		if code in seen:
 			continue
@@ -674,9 +674,9 @@ def _writeUnicodes(glyphObject, writer):
 		writer.simpletag("unicode", hex=hexCode)
 		writer.newline()
 
-def _writeNote(glyphObject, writer):
+def _writeNote(glyphObject, writer, validate):
 	note = getattr(glyphObject, "note", None)
-	if not isinstance(note, basestring):
+	if validate and not isinstance(note, basestring):
 		raise GlifLibError("note attribute must be str or unicode")
 	note = note.encode("utf-8")
 	writer.begintag("note")
@@ -727,7 +727,7 @@ def _writeGuidelines(glyphObject, writer, identifiers, validate):
 			attrs.append(("color", color))
 		identifier = guideline.get("identifier")
 		if identifier is not None:
-			if identifier in identifiers:
+			if validate and identifier in identifiers:
 				raise GlifLibError("identifier used more than once: %s" % identifier)
 			attrs.append(("identifier", identifier))
 			identifiers.add(identifier)
@@ -768,7 +768,7 @@ def _writeAnchors(glyphObject, writer, identifiers, validate):
 			attrs.append(("color", color))
 		identifier = anchor.get("identifier")
 		if identifier is not None:
-			if identifier in identifiers:
+			if validate and identifier in identifiers:
 				raise GlifLibError("identifier used more than once: %s" % identifier)
 			attrs.append(("identifier", identifier))
 			identifiers.add(identifier)
@@ -868,14 +868,14 @@ def _glifTreeFromString(aString):
 def _readGlyphFromTree(tree, glyphObject=None, pointPen=None, formatVersions=(1, 2), validate=False):
 	# check the format version
 	formatVersion = tree.get("format")
-	if formatVersion is None:
+	if validate and formatVersion is None:
 		raise GlifLibError("Unspecified format version in GLIF.")
 	try:
 		v = int(formatVersion)
 		formatVersion = v
 	except ValueError:
 		pass
-	if formatVersion not in formatVersions:
+	if validate and formatVersion not in formatVersions:
 		raise GlifLibError("Forbidden GLIF format version: %s" % formatVersion)
 	if formatVersion == 1:
 		_readGlyphFromTreeFormat1(tree=tree, glyphObject=glyphObject, pointPen=pointPen, validate=validate)
@@ -887,24 +887,25 @@ def _readGlyphFromTree(tree, glyphObject=None, pointPen=None, formatVersions=(1,
 
 def _readGlyphFromTreeFormat1(tree, glyphObject=None, pointPen=None, validate=None):
 	# get the name
-	_readName(glyphObject, tree)
+	_readName(glyphObject, tree, validate)
 	# populate the sub elements
 	unicodes = []
 	haveSeenAdvance = haveSeenOutline = haveSeenLib = haveSeenNote = False
 	for element in tree:
 		if element.tag == "outline":
-			if haveSeenOutline:
-				raise GlifLibError("The outline element occurs more than once.")
-			if element.attrib:
-				raise GlifLibError("The outline element contains unknown attributes.")
-			if element.text and element.text.strip() != '':
-				raise GlifLibError("Invalid outline structure.")
+			if validate:
+				if haveSeenOutline:
+					raise GlifLibError("The outline element occurs more than once.")
+				if element.attrib:
+					raise GlifLibError("The outline element contains unknown attributes.")
+				if element.text and element.text.strip() != '':
+					raise GlifLibError("Invalid outline structure.")
 			haveSeenOutline = True
 			buildOutlineFormat1(glyphObject, pointPen, element, validate)
 		elif glyphObject is None:
 			continue
 		elif element.tag == "advance":
-			if haveSeenAdvance:
+			if validate and haveSeenAdvance:
 				raise GlifLibError("The advance element occurs more than once.")
 			haveSeenAdvance = True
 			_readAdvance(glyphObject, element)
@@ -917,12 +918,12 @@ def _readGlyphFromTreeFormat1(tree, glyphObject=None, pointPen=None, validate=No
 			except ValueError:
 				raise GlifLibError("Illegal value for hex attribute of unicode element.")
 		elif element.tag == "note":
-			if haveSeenNote:
+			if validate and haveSeenNote:
 				raise GlifLibError("The note element occurs more than once.")
 			haveSeenNote = True
 			_readNote(glyphObject, element)
 		elif element.tag == "lib":
-			if haveSeenLib:
+			if validate and haveSeenLib:
 				raise GlifLibError("The lib element occurs more than once.")
 			haveSeenLib = True
 			_readLib(glyphObject, element, validate)
@@ -934,7 +935,7 @@ def _readGlyphFromTreeFormat1(tree, glyphObject=None, pointPen=None, validate=No
 
 def _readGlyphFromTreeFormat2(tree, glyphObject=None, pointPen=None, validate=None):
 	# get the name
-	_readName(glyphObject, tree)
+	_readName(glyphObject, tree, validate)
 	# populate the sub elements
 	unicodes = []
 	guidelines = []
@@ -943,19 +944,20 @@ def _readGlyphFromTreeFormat2(tree, glyphObject=None, pointPen=None, validate=No
 	identifiers = set()
 	for element in tree:
 		if element.tag == "outline":
-			if haveSeenOutline:
-				raise GlifLibError("The outline element occurs more than once.")
-			if element.attrib:
-				raise GlifLibError("The outline element contains unknown attributes.")
-			if element.text and element.text.strip() != '':
-				raise GlifLibError("Invalid outline structure.")
+			if validate:
+				if haveSeenOutline:
+					raise GlifLibError("The outline element occurs more than once.")
+				if element.attrib:
+					raise GlifLibError("The outline element contains unknown attributes.")
+				if element.text and element.text.strip() != '':
+					raise GlifLibError("Invalid outline structure.")
 			haveSeenOutline = True
 			if pointPen is not None:
 				buildOutlineFormat2(glyphObject, pointPen, element, identifiers, validate)
 		elif glyphObject is None:
 			continue
 		elif element.tag == "advance":
-			if haveSeenAdvance:
+			if validate and haveSeenAdvance:
 				raise GlifLibError("The advance element occurs more than once.")
 			haveSeenAdvance = True
 			_readAdvance(glyphObject, element)
@@ -968,33 +970,34 @@ def _readGlyphFromTreeFormat2(tree, glyphObject=None, pointPen=None, validate=No
 			except ValueError:
 				raise GlifLibError("Illegal value for hex attribute of unicode element.")
 		elif element.tag == "guideline":
-			if len(element):
+			if validate and len(element):
 				raise GlifLibError("Unknown children in guideline element.")
 			for attr in ("x", "y", "angle"):
 				if attr in element.attrib:
 					element.attrib[attr] = _number(element.attrib[attr])
 			guidelines.append(element.attrib)
 		elif element.tag == "anchor":
-			if len(element):
+			if validate and len(element):
 				raise GlifLibError("Unknown children in anchor element.")
 			for attr in ("x", "y"):
 				if attr in element.attrib:
 					element.attrib[attr] = _number(element.attrib[attr])
 			anchors.append(element.attrib)
 		elif element.tag == "image":
-			if haveSeenImage:
-				raise GlifLibError("The image element occurs more than once.")
-			if len(element):
-				raise GlifLibError("Unknown children in image element.")
+			if validate:
+				if haveSeenImage:
+					raise GlifLibError("The image element occurs more than once.")
+				if len(element):
+					raise GlifLibError("Unknown children in image element.")
 			haveSeenImage = True
 			_readImage(glyphObject, element, validate)
 		elif element.tag == "note":
-			if haveSeenNote:
+			if validate and haveSeenNote:
 				raise GlifLibError("The note element occurs more than once.")
 			haveSeenNote = True
 			_readNote(glyphObject, element)
 		elif element.tag == "lib":
-			if haveSeenLib:
+			if validate and haveSeenLib:
 				raise GlifLibError("The lib element occurs more than once.")
 			haveSeenLib = True
 			_readLib(glyphObject, element, validate)
@@ -1005,18 +1008,18 @@ def _readGlyphFromTreeFormat2(tree, glyphObject=None, pointPen=None, validate=No
 		_relaxedSetattr(glyphObject, "unicodes", unicodes)
 	# set the collected guidelines
 	if guidelines:
-		if not guidelinesValidator(guidelines, identifiers):
+		if validate and not guidelinesValidator(guidelines, identifiers):
 			raise GlifLibError("The guidelines are improperly formatted.")
 		_relaxedSetattr(glyphObject, "guidelines", guidelines)
 	# set the collected anchors
 	if anchors:
-		if not anchorsValidator(anchors, identifiers):
+		if validate and not anchorsValidator(anchors, identifiers):
 			raise GlifLibError("The anchors are improperly formatted.")
 		_relaxedSetattr(glyphObject, "anchors", anchors)
 
-def _readName(glyphObject, root):
+def _readName(glyphObject, root, validate):
 	glyphName = root.get("name")
-	if not glyphName:
+	if validate and not glyphName:
 		raise GlifLibError("Empty glyph name in GLIF.")
 	if glyphName and glyphObject is not None:
 		_relaxedSetattr(glyphObject, "name", glyphName)
@@ -1072,7 +1075,7 @@ def buildOutlineFormat1(glyphObject, pen, outline, validate):
 			if len(element) == 1:
 				point = element[0]
 				if point.tag == "point":
-					anchor = _buildAnchorFormat1(point)
+					anchor = _buildAnchorFormat1(point, validate)
 					if anchor is not None:
 						anchors.append(anchor)
 						continue
@@ -1080,7 +1083,7 @@ def buildOutlineFormat1(glyphObject, pen, outline, validate):
 				_buildOutlineContourFormat1(pen, element, validate)
 		elif element.tag == "component":
 			if pen is not None:
-				_buildOutlineComponentFormat1(pen, element)
+				_buildOutlineComponentFormat1(pen, element, validate)
 		else:
 			raise GlifLibError("Unknown element in outline element: %s" % element)
 	if glyphObject is not None and anchors:
@@ -1088,7 +1091,7 @@ def buildOutlineFormat1(glyphObject, pen, outline, validate):
 			raise GlifLibError("GLIF 1 anchors are not properly formatted.")
 		_relaxedSetattr(glyphObject, "anchors", anchors)
 
-def _buildAnchorFormat1(point):
+def _buildAnchorFormat1(point, validate):
 	if point.get("type") != "move":
 		return None
 	name = point.get("name")
@@ -1096,9 +1099,9 @@ def _buildAnchorFormat1(point):
 		return None
 	x = point.get("x")
 	y = point.get("y")
-	if x is None:
+	if validate and x is None:
 		raise GlifLibError("Required x attribute is missing in point element.")
-	if y is None:
+	if validate and y is None:
 		raise GlifLibError("Required y attribute is missing in point element.")
 	x = _number(x)
 	y = _number(y)
@@ -1106,7 +1109,7 @@ def _buildAnchorFormat1(point):
 	return anchor
 
 def _buildOutlineContourFormat1(pen, contour, validate):
-	if contour.attrib:
+	if validate and contour.attrib:
 		raise GlifLibError("Unknown attributes in contour element.")
 	pen.beginPath()
 	if len(contour):
@@ -1123,14 +1126,15 @@ def _buildOutlinePointsFormat1(pen, contour):
 		name = element.attrib["name"]
 		pen.addPoint((x, y), segmentType=segmentType, smooth=smooth, name=name)
 
-def _buildOutlineComponentFormat1(pen, component):
-	if len(component):
-		raise GlifLibError("Unknown child elements of component element.")
-	for attr in component.attrib.keys():
-		if attr not in componentAttributesFormat1:
-			raise GlifLibError("Unknown attribute in component element: %s" % attr)
+def _buildOutlineComponentFormat1(pen, component, validate):
+	if validate:
+		if len(component):
+			raise GlifLibError("Unknown child elements of component element.")
+		for attr in component.attrib.keys():
+			if attr not in componentAttributesFormat1:
+				raise GlifLibError("Unknown attribute in component element: %s" % attr)
 	baseGlyphName = component.get("base")
-	if baseGlyphName is None:
+	if validate and baseGlyphName is None:
 		raise GlifLibError("The base attribute is not defined in the component.")
 	transformation = []
 	for attr, default in _transformationInfo:
@@ -1154,15 +1158,17 @@ def buildOutlineFormat2(glyphObject, pen, outline, identifiers, validate):
 			raise GlifLibError("Unknown element in outline element: %s" % element.tag)
 
 def _buildOutlineContourFormat2(pen, contour, identifiers, validate):
-	for attr in contour.attrib.keys():
-		if attr not in contourAttributesFormat2:
-			raise GlifLibError("Unknown attribute in contour element: %s" % attr)
+	if validate:
+		for attr in contour.attrib.keys():
+			if attr not in contourAttributesFormat2:
+				raise GlifLibError("Unknown attribute in contour element: %s" % attr)
 	identifier = contour.get("identifier")
 	if identifier is not None:
-		if identifier in identifiers:
-			raise GlifLibError("The identifier %s is used more than once." % identifier)
-		if validate and not identifierValidator(identifier):
-			raise GlifLibError("The contour identifier %s is not valid." % identifier)
+		if validate:
+			if identifier in identifiers:
+				raise GlifLibError("The identifier %s is used more than once." % identifier)
+			if not identifierValidator(identifier):
+				raise GlifLibError("The contour identifier %s is not valid." % identifier)
 		identifiers.add(identifier)
 	try:
 		pen.beginPath(identifier=identifier)
@@ -1183,10 +1189,11 @@ def _buildOutlinePointsFormat2(pen, contour, identifiers, validate):
 		name = element.attrib["name"]
 		identifier = element.get("identifier")
 		if identifier is not None:
-			if identifier in identifiers:
-				raise GlifLibError("The identifier %s is used more than once." % identifier)
-			if validate and not identifierValidator(identifier):
-				raise GlifLibError("The identifier %s is not valid." % identifier)
+			if validate:
+				if identifier in identifiers:
+					raise GlifLibError("The identifier %s is used more than once." % identifier)
+				if not identifierValidator(identifier):
+					raise GlifLibError("The identifier %s is not valid." % identifier)
 			identifiers.add(identifier)
 		try:
 			pen.addPoint((x, y), segmentType=segmentType, smooth=smooth, name=name, identifier=identifier)
@@ -1195,13 +1202,14 @@ def _buildOutlinePointsFormat2(pen, contour, identifiers, validate):
 			warn("The addPoint method needs an identifier kwarg. The point's identifier value has been discarded.", DeprecationWarning)
 
 def _buildOutlineComponentFormat2(pen, component, identifiers, validate):
-	if len(component):
-		raise GlifLibError("Unknown child elements of component element.")
-	for attr in component.attrib.keys():
-		if attr not in componentAttributesFormat2:
-			raise GlifLibError("Unknown attribute in component element: %s" % attr)
+	if validate:
+		if len(component):
+			raise GlifLibError("Unknown child elements of component element.")
+		for attr in component.attrib.keys():
+			if attr not in componentAttributesFormat2:
+				raise GlifLibError("Unknown attribute in component element: %s" % attr)
 	baseGlyphName = component.get("base")
-	if baseGlyphName is None:
+	if validate and baseGlyphName is None:
 		raise GlifLibError("The base attribute is not defined in the component.")
 	transformation = []
 	for attr, default in _transformationInfo:
@@ -1213,10 +1221,11 @@ def _buildOutlineComponentFormat2(pen, component, identifiers, validate):
 		transformation.append(value)
 	identifier = component.get("identifier")
 	if identifier is not None:
-		if identifier in identifiers:
-			raise GlifLibError("The identifier %s is used more than once." % identifier)
-		if validate and not identifierValidator(identifier):
-			raise GlifLibError("The identifier %s is not valid." % identifier)
+		if validate:
+			if identifier in identifiers:
+				raise GlifLibError("The identifier %s is used more than once." % identifier)
+			if validate and not identifierValidator(identifier):
+				raise GlifLibError("The identifier %s is not valid." % identifier)
 		identifiers.add(identifier)
 	try:
 		pen.addComponent(baseGlyphName, tuple(transformation), identifier=identifier)
@@ -1496,10 +1505,11 @@ class GLIFPointPen(AbstractPointPen):
 	def beginPath(self, identifier=None, **kwargs):
 		attrs = []
 		if identifier is not None and self.formatVersion >= 2:
-			if identifier in self.identifiers:
-				raise GlifLibError("identifier used more than once: %s" % identifier)
-			if self.validate and not identifierValidator(identifier):
-				raise GlifLibError("identifier not formatted properly: %s" % identifier)
+			if self.validate:
+				if identifier in self.identifiers:
+					raise GlifLibError("identifier used more than once: %s" % identifier)
+				if not identifierValidator(identifier):
+					raise GlifLibError("identifier not formatted properly: %s" % identifier)
 			attrs.append(("identifier", identifier))
 			self.identifiers.add(identifier)
 		self.writer.begintag("contour", attrs)
@@ -1508,7 +1518,7 @@ class GLIFPointPen(AbstractPointPen):
 
 	def endPath(self):
 		if self.prevPointTypes and self.prevPointTypes[0] == "move":
-			if self.prevPointTypes[-1] == "offcurve":
+			if self.validate and self.prevPointTypes[-1] == "offcurve":
 				raise GlifLibError("open contour has loose offcurve point")
 		self.writer.endtag("contour")
 		self.writer.newline()
@@ -1520,20 +1530,22 @@ class GLIFPointPen(AbstractPointPen):
 		attrs = []
 		# coordinates
 		if pt is not None:
-			for coord in pt:
-				if not isinstance(coord, (int, float)):
-					raise GlifLibError("coordinates must be int or float")
+			if self.validate:
+				for coord in pt:
+					if not isinstance(coord, (int, float)):
+						raise GlifLibError("coordinates must be int or float")
 			attrs.append(("x", repr(pt[0])))
 			attrs.append(("y", repr(pt[1])))
 		# segment type
 		if segmentType == "offcurve":
 			segmentType = None
-		if segmentType == "move" and self.prevPointTypes:
-			raise GlifLibError("move occurs after a point has already been added to the contour.")
-		if segmentType in ("move", "line") and self.prevPointTypes and self.prevPointTypes[-1] == "offcurve":
-			raise GlifLibError("offcurve occurs before %s point." % segmentType)
-		if segmentType == "curve" and self.prevOffCurveCount > 2:
-			raise GlifLibError("too many offcurve points before curve point.")
+		if self.validate:
+			if segmentType == "move" and self.prevPointTypes:
+				raise GlifLibError("move occurs after a point has already been added to the contour.")
+			if segmentType in ("move", "line") and self.prevPointTypes and self.prevPointTypes[-1] == "offcurve":
+				raise GlifLibError("offcurve occurs before %s point." % segmentType)
+			if segmentType == "curve" and self.prevOffCurveCount > 2:
+				raise GlifLibError("too many offcurve points before curve point.")
 		if segmentType is not None:
 			attrs.append(("type", segmentType))
 		else:
@@ -1545,7 +1557,7 @@ class GLIFPointPen(AbstractPointPen):
 		self.prevPointTypes.append(segmentType)
 		# smooth
 		if smooth:
-			if segmentType == "offcurve":
+			if self.validate and segmentType == "offcurve":
 				raise GlifLibError("can't set smooth in an offcurve point.")
 			attrs.append(("smooth", "yes"))
 		# name
@@ -1553,10 +1565,11 @@ class GLIFPointPen(AbstractPointPen):
 			attrs.append(("name", name))
 		# identifier
 		if identifier is not None and self.formatVersion >= 2:
-			if identifier in self.identifiers:
-				raise GlifLibError("identifier used more than once: %s" % identifier)
-			if self.validate and not identifierValidator(identifier):
-				raise GlifLibError("identifier not formatted properly: %s" % identifier)
+			if self.validate:
+				if identifier in self.identifiers:
+					raise GlifLibError("identifier used more than once: %s" % identifier)
+				if not identifierValidator(identifier):
+					raise GlifLibError("identifier not formatted properly: %s" % identifier)
 			attrs.append(("identifier", identifier))
 			self.identifiers.add(identifier)
 		self.writer.simpletag("point", attrs)
@@ -1565,15 +1578,16 @@ class GLIFPointPen(AbstractPointPen):
 	def addComponent(self, glyphName, transformation, identifier=None, **kwargs):
 		attrs = [("base", glyphName)]
 		for (attr, default), value in zip(_transformationInfo, transformation):
-			if not isinstance(value, (int, float)):
+			if self.validate and not isinstance(value, (int, float)):
 				raise GlifLibError("transformation values must be int or float")
 			if value != default:
 				attrs.append((attr, repr(value)))
 		if identifier is not None and self.formatVersion >= 2:
-			if identifier in self.identifiers:
-				raise GlifLibError("identifier used more than once: %s" % identifier)
-			if self.validate and not identifierValidator(identifier):
-				raise GlifLibError("identifier not formatted properly: %s" % identifier)
+			if self.validate:
+				if identifier in self.identifiers:
+					raise GlifLibError("identifier used more than once: %s" % identifier)
+				if self.validate and not identifierValidator(identifier):
+					raise GlifLibError("identifier not formatted properly: %s" % identifier)
 			attrs.append(("identifier", identifier))
 			self.identifiers.add(identifier)
 		self.writer.simpletag("component", attrs)
diff --git a/Lib/ufoLib/test/test_GLIF1.py b/Lib/ufoLib/test/test_GLIF1.py
index 9b3c4bf42..e7ea66b79 100644
--- a/Lib/ufoLib/test/test_GLIF1.py
+++ b/Lib/ufoLib/test/test_GLIF1.py
@@ -24,7 +24,7 @@ class TestGLIF1(unittest.TestCase):
 		py = stripText(py)
 		glyph = Glyph()
 		exec(py, {"glyph" : glyph, "pointPen" : glyph})
-		glif = writeGlyphToString(glyph.name, glyphObject=glyph, drawPointsFunc=glyph.drawPoints, formatVersion=1)
+		glif = writeGlyphToString(glyph.name, glyphObject=glyph, drawPointsFunc=glyph.drawPoints, formatVersion=1, validate=True)
 		glif = "\n".join(glif.splitlines()[1:])
 		return glif
 
@@ -32,7 +32,7 @@ class TestGLIF1(unittest.TestCase):
 		glif = stripText(glif)
 		glif = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n" + glif
 		glyph = Glyph()
-		readGlyphFromString(glif, glyphObject=glyph, pointPen=glyph)
+		readGlyphFromString(glif, glyphObject=glyph, pointPen=glyph, validate=True)
 		return glyph.py()
 
 	def testTopElement(self):
diff --git a/Lib/ufoLib/test/test_GLIF2.py b/Lib/ufoLib/test/test_GLIF2.py
index c907f0769..b614a8d54 100644
--- a/Lib/ufoLib/test/test_GLIF2.py
+++ b/Lib/ufoLib/test/test_GLIF2.py
@@ -24,7 +24,7 @@ class TestGLIF2(unittest.TestCase):
 		py = stripText(py)
 		glyph = Glyph()
 		exec(py, {"glyph" : glyph, "pointPen" : glyph})
-		glif = writeGlyphToString(glyph.name, glyphObject=glyph, drawPointsFunc=glyph.drawPoints, formatVersion=2)
+		glif = writeGlyphToString(glyph.name, glyphObject=glyph, drawPointsFunc=glyph.drawPoints, formatVersion=2, validate=True)
 		glif = "\n".join(glif.splitlines()[1:])
 		return glif