diff --git a/CHANGES.txt b/CHANGES.txt
index 0b0a3dd55..6036626af 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -5,6 +5,11 @@ HISTORY
 1.2.11 (unreleased)
 -------------------
 
+- Determine mimetype correctly for plone.app.textfield RichText widgets with
+  ignoreContext = True (such as on add forms).
+  (Requires plone.app.textfield >= 1.1.1)
+  [davisagli]
+
 - Removed comma at the end of a dict in tiny_mce_init.js. This fixes javascript
   error on IE7. This was broken in 1.2.10.
   [vincentfretin]
diff --git a/Products/TinyMCE/skins/tinymce/tinymce_wysiwyg_support.pt b/Products/TinyMCE/skins/tinymce/tinymce_wysiwyg_support.pt
index ba50385f0..edb6ae376 100644
--- a/Products/TinyMCE/skins/tinymce/tinymce_wysiwyg_support.pt
+++ b/Products/TinyMCE/skins/tinymce/tinymce_wysiwyg_support.pt
@@ -6,7 +6,8 @@
   <tal:block define="field field|nothing;
                      fname fieldName|inputname|nothing;
                      force_wysiwyg force_wysiwyg|nothing;
-                     text_format python:here.portal_tinymce.getContentType(object=here, fieldname=fname);
+                     object object|here;
+                     text_format python:here.portal_tinymce.getContentType(object=object, field=field, fieldname=fname);
                      suppressed python:request.form.get('tinymce.suppress') == fname;
                      wysiwyg python:(not suppressed and 'html' in text_format.lower()) or force_wysiwyg;
                      configuration_method nocall:here/@@tinymce-jsonconfiguration;
diff --git a/Products/TinyMCE/utility.py b/Products/TinyMCE/utility.py
index d27569f01..3e9ca6d06 100644
--- a/Products/TinyMCE/utility.py
+++ b/Products/TinyMCE/utility.py
@@ -9,6 +9,7 @@
 from zope.i18nmessageid import MessageFactory
 from zope.interface import classProvides
 from zope.interface import implements
+from zope.interface import Interface
 from zope.schema.fieldproperty import FieldProperty
 from zope.globalrequest import getRequest
 from AccessControl import ClassSecurityInfo
@@ -38,6 +39,13 @@
 from Products.TinyMCE import TMCEMessageFactory as _
 
 
+try:
+    from plone.app.textfield.interfaces import IRichText
+except ImportError:
+    class IRichText(Interface):
+        pass
+
+
 def form_adapter(context):
     """Form Adapter"""
     return getUtility(ITinyMCE)
@@ -577,18 +585,34 @@ def getValidElements(self):
         return valid_elements
 
     security.declareProtected('View', 'getContentType')
-    def getContentType(self, object=None, fieldname=None):
+    def getContentType(self, object=None, field=None, fieldname=None):
         context = aq_base(object)
-        if IBaseObject.providedBy(context):
+        if context is not None and IBaseObject.providedBy(context):
             # support Archetypes fields
-            if fieldname is None:
-                field = context.getPrimaryField()
-            else:
+            if field is not None:
+                pass
+            elif fieldname is not None:
                 field = context.getField(fieldname) or getattr(context, fieldname, None)
+            else:
+                field = context.getPrimaryField()
             if field and hasattr(aq_base(field), 'getContentType'):
                 return field.getContentType(context)
-        elif '.widgets.' in fieldname:
+        elif IRichText.providedBy(field):
             # support plone.app.textfield RichTextValues
+
+            # First try to get a stored value and check its mimetype.
+            mimetype = None
+            if context is not None:
+                value = getattr(context, fieldname, None)
+                mimetype = getattr(value, 'mimeType', None)
+
+            # Fall back to the field's default mimetype
+            if mimetype is None:
+                mimetype = field.default_mime_type
+            return mimetype
+        elif context is not None and fieldname is not None and '.widgets.' in fieldname:
+            # We don't have the field object but we can at least try
+            # to get the mimetype from an attribute on the object
             fieldname = fieldname.split('.widgets.')[-1]
             field = getattr(context, fieldname, None)
             mimetype = getattr(field, 'mimeType', None)