For hologram i used green laser and exposure was 30 sec. For Lippmann photography i used light in room and two lamp with white paper glued to lamp with exposure 4 min. Maybe this lights arenŽt so powerfull as day light and I need longer exposure. Hope I understand your question right.
IŽll try natural drying too if u mean without glycerol and alcohol bath. But still suprised that there is really nothing even hint of something. Thanks for idea I try it and let you know.
For Lippmann plates you will need 4-5 min bright sunlight @ f4.5 to get something,and you will need to adjust that according to how the plates develop out