Hi everyone,
I am new to this forum and new to holography.
I am planning to start with Denisyuk reflection holograms using a 5mw 650nm laser diode.
Q1: should I opt for PFG-3m or the older PFG-1 plates to start with?
Q2: is the recording / developing of PFG-3m more difficult than PFG-1 ? Is the viewing experience (depth of field, resolution) much better than PFG-1?
I will be buying plates & chemicals from geola.com
Geola.com states:
"Ultra-fine grain emulsions provide a bit more clear image than fine grain ones, but are very soft and are not recommended for hobbyists and beginners due to quite difficult processing and shorter life time."
(https://www.geola.com/product/pfg-03m-plates/)
On the other hand, integraf.com says: “Highest resolution available, Exceptional for reflection holograms and Recommended for teachers & hobbyists”
(https://www.integraf.com/shop/pfg-03m-h ... ilm-plates)
thank you
PFG-3m vs PFG-1
Re: PFG-3m vs PFG-1
Start with 01
As Geola states, 03 is very soft. This requires pre-hardening as well as careful processing, you need to use a high gamma developer (one that develops at a high resolution), and be careful of bleach times to avoid noise. As a beginner, you'd be better off with the 01.Cycy wrote: ↑Sat Dec 30, 2023 5:51 pm Q2: is the recording / developing of PFG-3m more difficult than PFG-1 ? Is the viewing experience (depth of field, resolution) much better than PFG-1?
I will be buying plates & chemicals from geola.com
Geola.com states:
"Ultra-fine grain emulsions provide a bit more clear image than fine grain ones, but are very soft and are not recommended for hobbyists and beginners due to quite difficult processing and shorter life time."
(https://www.geola.com/product/pfg-03m-plates/)
On the other hand, integraf.com says: “Highest resolution available, Exceptional for reflection holograms and Recommended for teachers & hobbyists”
(https://www.integraf.com/shop/pfg-03m-h ... ilm-plates)
thank you
The word "resolution" refers to the resolution of the medium, not the image - a common error; I've seen statements that holograms have a resolution of so many dpi, or been asked how many dpi is a hologram. A holographic image is continuous (within certain constraints such as uniformity of recon and material, and human eye acuity), and therefore has a dpi of infinity, just as real world objects have a dpi of infinity - the real world is not pixelated. For a medium, the resolution is the minimum spacing in the plane structure; the hologram consisting of a set of planes within the medium. For example, a reflection hologram has plane structure of ~3000 l/mm - ie there are 3000 planes within one millimetre and therefore, the plane separation is about 0.3 micron or about 1/100 the thickness of a human hair. So, if the material cannot resolve 3000 planes within one millimetre the hologram will be noisy.
Here is the resolution of PFG-01 from the Geola site:
"This Silver Halide photomaterial is used in art holography (one or two steps holograms recording). Resolution: more than 3000 lines/millimeter."
The depth of field of a holographic image is based on the coherence length of your laser, it has no bearing on the film resolution (provided film resolution is greater than the plane separation). It depends whether the coherence of the laser is greater than the path length difference between the front of object and back of object and the distance of the front of the object to the plate. So, let's say you're shooting something about 3 inches long, placed with the front end about an inch from the plate in a single beam Denisyuk geometry. Then the path difference to the back of the object from the front of the plate is 4 inches, and your coherence length should be at least that, preferably longer.