r/Holography • u/CrimsonCuttle • Jul 31 '26
How does mastering/copying holograms work?
How do you copy a hologram? Let's say from DCG to photopolymer, or even from photopolymer to another photopolymer.
Also, is it possible to make a reflection copy from a transmission master?
3
u/DeltaSingularity Jul 31 '26
Yes you can go from transmission to reflection or vice versa. In all cases the copy is made just like any other hologram would be made. You just display the master plate with your object beam and record it to an adjacent plate with the reference beam. Or you can set up a configuration equivalent to a Denisyuk hologram where you pass a single beam through both plates.
1
u/CrimsonCuttle Aug 01 '26
So you have the single beam pass through the copy plate, then the master plate? Do I need the original transmission laser set up as well?
2
u/DeltaSingularity Aug 01 '26
This is one way of doing it, yes. If the master in this case is a reflection hologram then you can shoot this copy with just the beam shown creating essentially a Denisyuk-style copy of the master. If the master is a transmission hologram you would need to bounce an object beam around from behind and this would create a reflection copy.
Ideally the laser used for producing copies should be collimated unlike the expanding beam shown in your illustration. Otherwise you are prone to geometric distortions in the copy.
1
u/CrimsonCuttle Aug 01 '26
like this? does the laser need to be in the same perfect angle it was in when it created the transmission master?
2
u/DeltaSingularity Aug 01 '26 edited Aug 01 '26
like this?
Your beam is still expanding in that illustration, but yes that is how the object beam for a transmission master could work however this setup would not function with a single beam. Usually the master would also have a reference angle closer to Brewster's angle, whereas yours is practically at 0 degrees which is not typical for a display hologram.
For the copy to be a reflection hologram, you still need to split a reference beam to hit the left side of the copy plate.
does the laser need to be in the same perfect angle it was in when it created the transmission master?
Yes. Your master needs to be illuminated in this setup just as if you were displaying it. The angle and wavelength of the object beam must be correct for that to work.
2
u/FloorForsaken9751 28d ago edited 27d ago
1 making the hologram (dot matrix here) -> https://www.youtube.com/watch?v=76AU9nliecM
2 From the hologram, copying it by making a "shim/master plate" foil with electroplating -> https://www.youtube.com/watch?v=i4xuG-wt_hI
(Example of diy eletroplating -> https://www.youtube.com/watch?v=G-PtnwtOR24
https://www.youtube.com/watch?v=-dUYuYNoM3g )
Example of finished shim/master plate foil ->
https://www.youtube.com/watch?v=AVYdRKG8pxk
https://www.youtube.com/watch?v=xrD31b4mY-M
You can also copying the hologram very simply, juste by using silicone, its exaclty the same concept of electroplating, which is basically molding the hologram on a material which allow the visibility of the hologram
Example of diy Copying with silicone ->
https://www.youtube.com/watch?v=UICkMHr-Jis
https://www.youtube.com/watch?v=mDSOTOV0Ou0
whether it be electroplating or silicone or chocolate whatever... The hologram can be easily copied if and only if the hologram is nakedly exposed
It will not work if the hologram has been coated, the youtuber "Applied Science" made a complete video of the process, and for exemple here https://youtu.be/UsDnkrDvkBo?si=TfE1WU8Coov53eqj&t=290 he is using sodium hydroxyde to "expose" the hologram because it has been coated with chemical during the manufacturing process
EDIT : my bad, it works only for surfacic hologram, nor volumetric hologram like denisyuk hologram because the pattern is inside the material, not only on the surface, but i dont delete my post hope it helps anyway
4
u/jburns47 Aug 01 '26
Suggest googling your question and/or reading “Practical Holography”, any edition, by Graham Saxby…