diff --git a/README.md b/README.md
index 895abd8..b137458 100644
--- a/README.md
+++ b/README.md
@@ -4,6 +4,8 @@ Collection of tools, their source code and design files for communicating with *
 
 See http://furrtek.free.fr/index.php?a=esl for more details.
 
+Thanks to @david4599 for infos about color tags.
+
 ## Hardware
 
 * ir_tx_serial: Simple DIY serial port transmitter, using an USB-serial cable.
diff --git a/images/color.png b/images/color.png
new file mode 100644
index 0000000..82ef7a6
Binary files /dev/null and b/images/color.png differ
diff --git a/tools_python/img2dm.py b/tools_python/img2dm.py
index 454a1d1..623c6b2 100644
--- a/tools_python/img2dm.py
+++ b/tools_python/img2dm.py
@@ -7,6 +7,21 @@ import tx
 from imageio import imread
 import sys
 
+bytes_per_frame = 20
+bits_per_frame = bytes_per_frame * 8
+
+def image_convert(image, color_pass):
+	pixels = []
+	for row in image:
+		for rgb in row:
+			luma = 0.21 * rgb[0] + 0.72 * rgb[1] + 0.07 * rgb[2]
+			if color_pass:
+				pixels.append(0 if luma >= 0.33 and luma < 0.66 else 1)	# 0 codes color (anything mid grey)
+			else:
+				pixels.append(0 if luma < 0.5 else 1)	# 0 codes black
+	        	
+	return pixels
+
 def record_run(run_count):
     # Convert to binary
     del bits[:]
@@ -22,18 +37,27 @@ def record_run(run_count):
 def usage():
     print("img2dm - Transmits image to Dot Matrix ESL\n")
     print("Usage:")
-    print("img2dm.py port image barcode page (x y)\n")
+    print("img2dm.py port image barcode (page color x y)\n")
     print("  port: serial port name (0 for ESL Blaster)")
     print("  image: image file")
     print("  barcode: 17-character barcode data")
-    print("  page: page number to update (0~15)")
+    print("  page: page number to update (0~15), default: 0")
+    print("  color: 0:Black and white only, 1:Color-capable ESL, default: 0")
     print("  x y: top-left position of image, default: 0 0")
     exit()
 
 arg_count = len(sys.argv)
-if arg_count < 5:
+if arg_count < 4:
     usage()
 
+if arg_count >= 5:
+	page = int(sys.argv[4])
+	if page < 0 or page > 15:
+	    print("Page must be between 0 and 15.")
+	    exit()
+else:
+	page = 0
+
 port = sys.argv[1]
 
 # Search for connected ESL Blaster if required
@@ -46,39 +70,28 @@ if (port == "0"):
 image = imread(sys.argv[2])
 width = image.shape[1]
 height = image.shape[0]
-if width > 208 or height > 112:
-    print("Image should be 208*112 pixels or less.")
-    exit()
+# Medium size is 208*112
+print("Image is %i*%i, please make sure that this is equal or less than the ESL's display size." % (width, height))
 
 # Get PLID from barcode string
 PLID = pr.get_plid(sys.argv[3])
 
-page = int(sys.argv[4])
-if page < 0 or page > 15:
-    print("Page can only be between 0 and 15.")
-    exit()
+color_mode = int(sys.argv[5]) if arg_count >= 6 else 0
+pos_x = int(sys.argv[6]) if arg_count >= 7 else 0
+pos_y = int(sys.argv[7]) if arg_count >= 8 else 0
 
-if arg_count > 5:
-    pos_x = int(sys.argv[5])
-else:
-    pos_x = 0
-if arg_count > 6:
-    pos_y = int(sys.argv[6])
-else:
-    pos_y = 0
+# First pass for black and white
+pixels = image_convert(image, 0)
 
-bits = []
-size_raw = width * height
+if color_mode:
+	# Append second pass for color  if needed
+	pixels += image_convert(image, 1)
 
-# Convert image to 1-bit
-pixels = []
-for row in image:
-    for rgb in row:
-        pixels.append(int(round((0.21 * rgb[0] + 0.72 * rgb[1] + 0.07 * rgb[2]) / 255)))
-
-print("Compressing %i pixels..." % size_raw)
+size_raw = len(pixels)
+print("Compressing %i bits..." % size_raw)
 
 # First pixel
+bits = []
 compressed = []
 run_pixel = pixels[0]
 run_count = 1
@@ -100,6 +113,7 @@ if run_count > 1:
 size_compressed = len(compressed)
 
 # Decide on compression or not
+# size_compressed = size_raw # Disable compression
 if size_compressed < size_raw:
     print("Compression ratio: %.1f%%" % (100 - ((size_compressed * 100) / float(size_raw))))
     data = compressed
@@ -110,7 +124,6 @@ else:
     compression_type = 0
 
 # Pad data to multiple of bits_per_frame
-bits_per_frame = 20 * 8
 data_size = len(data)
 padding = bits_per_frame - (data_size % bits_per_frame)
 for b in range(0, padding):
@@ -119,17 +132,19 @@ for b in range(0, padding):
 padded_data_size = len(data)
 frame_count = padded_data_size // bits_per_frame
 
+print("Data size: %i (%i frames)" % (data_size, frame_count))
+
 frames = []
 
-# Ping frame
+# Wake-up ping frame
 frames.append(pr.make_ping_frame(PLID, 400))
 
-print("Generating %i data frames..." % frame_count)
+print("Generating frames...")
 
 # Parameters frame
 frame = pr.make_mcu_frame(PLID, 0x05)
-pr.append_word(frame, data_size // 8)   # Byte count
-frame.append(0x00)                      # Unused
+pr.append_word(frame, data_size // 8)	# Total byte count for group
+frame.append(0x00)              # Unused
 frame.append(compression_type)
 frame.append(page)
 pr.append_word(frame, width)
@@ -148,7 +163,7 @@ i = 0
 for fr in range(0, frame_count):
     frame = pr.make_mcu_frame(PLID, 0x20)
     pr.append_word(frame, fr)
-    for by in range(0, 20):
+    for by in range(0, bytes_per_frame):
         v = 0
         # Bit string to byte
         for bi in range(0, 8):
@@ -163,12 +178,13 @@ for fr in range(0, frame_count):
 frames.append(pr.make_refresh_frame(PLID))
 
 # DEBUG
-#f = open("out.txt", "w")
-#for fr in frames:
-#    for b in fr:
-#        f.write(format(b, '02X') + " ")
-#    f.write("\n")
-#exit()
+f = open("frames.txt", "w")
+for fr in frames:
+    for b in fr:
+        f.write(format(b, '02X') + " ")
+    f.write("\n")
+
+input("Place ESL in front of transmitter and press any key.")
 
 # Send data to IR transmitter
 if (port == "0"):
diff --git a/tools_python/pr.py b/tools_python/pr.py
index 0f8e1f2..6be92dd 100644
--- a/tools_python/pr.py
+++ b/tools_python/pr.py
@@ -48,7 +48,7 @@ def get_plid(barcode):
     return PLID
 
 def make_ping_frame(PLID, repeats):
-    frame = make_raw_frame(0x85, PLID, 0x17)
+    frame = make_raw_frame(0x85, PLID, 0x17)	# 0x97 ?
     frame.append(0x01)
     frame.append(0x00)
     frame.append(0x00)