Скачать или смотреть PTFE White balance targets for Ultraviolet Photography

Testing:

Can we use some non-PTFE material with thin PTFE or PTFE tape on top as a WB target, or does the non-PTFE material show through and affect the result?
The non-PTFE material does affect the result, and so needs to also be something that is neutral. The brown cardboard actually seems pretty neutral in UV, but it wouldn't be any good for visible light.

Is PTFE tape a suitable target?
Yes, but as per above it needs to be stuck on something else that is also neutral since it is translucent. Or you'd need a few layers of it. Both the cardboard and Tetra pak seem fine as base layers. The grey tape seems better as it is thicker, has adhesive pre-applied, and grey is more useful as a WB target since it needs no exposure adjustment to avoid over-exposing the target. It is not neutral in Vis though.

Is there any difference between the solid PTFE we have?
All seems pretty similar

00:00 Intro
01:28 Different pieces of 3mm thick PTFE
Testing thin PTFE (Grey adhesive backed plumber's tape, White non-adhesive plumber's tape, 0.1mm thick PTFE sheet, 0.25mm thick PTFE sheet) with various backing materials:
02:02 Foil side of Tetra Pak as backing
02:34 Brown cardboard as backing
03:09 2mm thick clear Perspex as backing
03:50 1mm thick transparent acrylic as backing
04:12 0.5mm thick PVC as backing
05:01 3mm thick PTFE as backing
05:29 Conclusion

Written version of this video is on my blog: https://www.davidkennardphotography.c...