Use white and buff thread (see Madeira colors to the right).
In order to cleanly execute the block H with the drop shadow, the embroidery process requires an outline around the H. This outline should MATCH the color of the fabric — which will effectively render the “outline around the H” invisible.
The desired effect will look like this:
Embroidery Thread Specifications
Hamilton colors Continental Blue (PMS 287 C) and Buff (PMS 467 C)
Madeira Polyneon Blue # 1843
Madeira Polyneon Buff # 1738
Robison-Anton Super Brite Polyester Blue #5738 (Blue Suede)
Robison-Anton Super Brite Polyester Buff #9125 (Rice Paper)
Robison-Anton Super Strength Rayon Blue #2210 (Royal)
Robison-Anton Super Strength Rayon Buff #2570 (Golden Tan)
Alternate choice if preferred thread is not available:
Madeira Rayon Blue #1166
Madeira Rayon Buff # 1084