One thing that makes working with our directors of photography so satisfying, is their ability to make interiors and make it look like people are outside. So they're interior-exterior daylight work is exceptional. A lot of times we'll create elements with the intention that they will never really be seen as they are. In that case, we wanted something a little strange and a little alien to feather into Kes as she's going through her transmutation.

Kes experiences the start of her transmutation in her quarters, shortly after insisting she (Kes) leave Voyager
the bottom left picture shows the special effect (not aired like this - see Dan Curry's words below), the other three are screenshots from the aired episode

So, again, in Photoshop, I did a freehand drawing of odd tissue and veiny things, inspired by water buffalo placenta. Then we would occasionally double-expose that into Kes as she's fluctuating in and out of our physical reality. Liquid nitrogen is one of the great materials for visual effects work. We just trickled it over black velvet on an inclined plane and it broke up in these little waves. We used that as a keying element. Because it's white over black you have enough contrast to create an electronic stencil, through which you can print other information. That's a piece of the puzzle that went into Kes' transmutation.

liquid nitrogen trickled over black velvet

Dan Curry, in his office