The UV/blacklight test is a bit of a myth. It only highlights (by glowing) white synthetic threads. So if something is fake but made with natural fibres such as silk or cotton it won't glow (only something like nylon or polyester will glow). Additionally they will only glow if white. Coloured materials don't tend to. These wings were made in rayon thread which has been coloured.
As for the backing, wings like these generally appear with a backing cloth in black with a tight weave (usually genuine) or a white backing with a very loose weave (repro, generally produced by the US firm Patch King in the 40s and 50s). The badge above clearly shows lose individual white threads which I'd guess come from a Patch King type repro. The threads can easily be pulled out to remove the backing giving the impression of an original. The white backing/individual threads may not glow for the reasons mentioned above.
|