The NEO Sun HB3206D-W2XL-K6 can use White and Varnish as Spot inks.
The NEO Sun FB3215-06DW2XL can use White.
To configure these inks, you need to go to the Page Setup module, open the corresponding tab, and then click on Enable separation:
Info
To have more details on the topic, please refer to this article dedicated to Spot Inks.
Double strike
At the lower part of the corresponding tabs, between Available Sources and Linearization, you will find an additional setting for the use of spot inks.
Double Strike: each dot is fired twice, and multiply the resolution passes by 2, which can lead to a theoretical 200% density compared to the original qualities.