Myth: A coloured ultrasound always has coloured images like yellowish etc which is better than a black and white ultrasound.
Facts: Gray scale is the key to radiological imaging. Coloured images (eg. Yellowish or Pinkish) are actually a change of tint of the gray scale image. See the example below.
Many doctors give a black and white print out on thermal paper roll which discriminates the grey shades better as well as saves time.