In the “Signs of the Times” featurette, from the five disc edition of Blade Runner, artist Tom Southwell says, about the creation of The White Dragon sign, “So, I got my book of neon out, and they had a picture of a really good dragon. So, I went ahead with that…”
The black and white photo in the triptych below is a post-WWII neon sign in Ogden, Utah, and was published in the book “Let There Be Neon” by Rudi Stern, in 1979.
The same book also contains another photo of a neon sign dragon, which is likely the origin of the green dragon sign in Blade Runner.
Here is the original Star Noodle dragon in color: Flickr