diff --git a/brother_ql/brother_ql_create.py b/brother_ql/brother_ql_create.py
index 04f2225..cccc052 100755
--- a/brother_ql/brother_ql_create.py
+++ b/brother_ql/brother_ql_create.py
@@ -5,6 +5,7 @@ from __future__ import division
 import sys, argparse, logging
 
 from PIL import Image
+import PIL.ImageOps
 
 from brother_ql.raster import BrotherQLRaster
 from brother_ql.devicedependent import models, label_type_specs, ENDLESS_LABEL, DIE_CUT_LABEL, ROUND_DIE_CUT_LABEL
@@ -100,6 +101,9 @@ def create_label(qlr, image, label_size, threshold=70, cut=True, **kwargs):
         new_im.paste(im, (device_pixel_width-im.size[0]-right_margin_dots, 0))
         im = new_im
 
+    im = PIL.ImageOps.invert(im)
+
+    threshold = 100.0 - threshold
     threshold = min(255, max(0, int(threshold/100.0 * 255))) # from percent to pixel val
     im = im.point(lambda x: 0 if x < threshold else 255, mode="1")
 
diff --git a/brother_ql/raster.py b/brother_ql/raster.py
index 086afbd..7e90df1 100644
--- a/brother_ql/raster.py
+++ b/brother_ql/raster.py
@@ -6,6 +6,7 @@ import logging
 
 import packbits
 from PIL import Image
+import io
 
 from .devicedependent import models, \
                              min_max_feed, \
@@ -19,6 +20,11 @@ from .devicedependent import models, \
 
 from . import BrotherQLError, BrotherQLUnsupportedCmd, BrotherQLUnknownModel, BrotherQLRasterError
 
+try:
+    from io import BytesIO
+except: # Py2
+    from cStringIO import StringIO as BytesIO
+
 logger = logging.getLogger(__name__)
 
 class BrotherQLRaster(object):
@@ -177,20 +183,19 @@ class BrotherQLRaster(object):
             fmt = 'Wrong pixel width: {}, expected {}'
             raise BrotherQLRasterError(fmt.format(image.size[0], self.get_pixel_width()))
         frame = bytes(image.tobytes(encoder_name='raw'))
-        # The above command directly returns the 1-bit image packed
-        # into bits. (The cast to bytes is needed for Py2 compatibility.)
-        frame = bytes([2**8 + ~byte for byte in frame]) # invert b/w
         frame_len = len(frame)
         row_len = image.size[0]//8
         start = 0
+        file_str = BytesIO()
         while start + row_len <= frame_len:
             row = frame[start:start+row_len]
             start += row_len
-            self.data += b'\x67\x00' # g 0x00
+            file_str.write(b'\x67\x00')
             if self._compression:
                 row = packbits.encode(row)
-            self.data += bytes([len(row)])
-            self.data += row
+            file_str.write(bytes([len(row)]))
+            file_str.write(row)
+        self.data += file_str.getvalue()
 
     def add_print(self, last_page=True):
         if last_page: