While the open, arched indices on Philippe Narbel's inaugural ROOTS timepiece appear to have been 3D printed, that has yet to be confirmed. However, he has been very open about the fact that the texture in the center of the dial is crafted from sterling silver using a technique he stumbled upon by accident while studying to become a jeweller. That technique is known within the jewellery industry as reticulation and involves removing the copper content from the surface of sterling silver, or other precious metal alloy, and then proceeding to melt the core of the metal without melting the surface. As the surface is now pure precious metal and has a higher melting point than the alloyed metal below it, the liquified material below it deforms the surface as it heats and cools.

The linked video, by Andrew Berry, provides a full walkthrough of the process, from material preparation all the way through to punching out a desired section of the reticulated metal without damaging the texture.