by Din » Fri Feb 07, 2020 9:22 am
You have the same white light speck in the photograph of the opal, but the white light on reconstruction is more pronounced. There are also specks of white on the acrylic in the reconstruction. How was the opal illuminated during recording? If it was a shadowgram, the white light could be a 'hole' in the opal where white light passes straight through.
By the way, an opal gets it's colours because of tiny voids in the interior. These voids act as diffractive structures, so, it works much like a dcg hologram. In a dcg hologram, the image appears in only one bandwidth, and disappears when you turn the hologram. When you turn the opal in white light, you get flashes of different colours. This is because the voids in a dcg hologram lie along the Bragg planes caused by the recording angles, while in the opal, the voids are randomly scattered.
You have the same white light speck in the photograph of the opal, but the white light on reconstruction is more pronounced. There are also specks of white on the acrylic in the reconstruction. How was the opal illuminated during recording? If it was a shadowgram, the white light could be a 'hole' in the opal where white light passes straight through.
By the way, an opal gets it's colours because of tiny voids in the interior. These voids act as diffractive structures, so, it works much like a dcg hologram. In a dcg hologram, the image appears in only one bandwidth, and disappears when you turn the hologram. When you turn the opal in white light, you get flashes of different colours. This is because the voids in a dcg hologram lie along the Bragg planes caused by the recording angles, while in the opal, the voids are randomly scattered.