Monochrome and Color Denisyuk Holograms from China

unixboy · Post by **unixboy** » Wed Jan 29, 2014 1:10 pm

Hello,
I had been a long time unregistered visitor of this forum and learnt a lot by reading the discussion threads of those experienced holographers. Since I began making holograms as a hobby in 2006, it has been a long way to study and to experiment by trial and error method. Most of my questions as a new holographer can be found in the archives and the new forum. I decided to register this forum as long as I make a hologram good enough to show or sell. Here I put two Denisyuk holograms with Chinese elements that I made for sale:
A monochrome Chinese dragon hologram, http://www.ebay.com/itm/151217751092
and a color "Wishes for your fortune" hologram, http://www.ebay.com/itm/151218100316

Comments and suggestions are welcome. Thanks.

unixboy · Post by **unixboy** » Fri Jan 31, 2014 1:24 pm

Thanks for the visitors of this post. The true color Denisyuk hologram was sold and a new one is listed. So the old link does not work anymore and please visit my profile for more new holograms at http://www.ebay.com/usr/unixboychina
BTW, I am so happy to see the works of holographers of this forum in the world. Holography and the forum made the world wonderful and small!
I probably should write the following in the thread of General Holography>introductions rather than here.
My first impression of full parallax holograms was in 1994 when I saw a laser transmission hologram and several image-plane DCG holograms in a science museum. Although rainbow holograms were introduced as security labels many years earlier, I was astonished by the realistic 3D images in science museum. Those were large and deep 3D images, very sharp and clear because of special reconstruction lighting for the display. The quality of such holograms are far better than any rainbow holograms I had ever seen before. As a student, I decided to make such holograms myself. However, such "dream" was a long and hard one to realize. During my teenage years, I was fascinated in black & white photography and darkroom processing. By reading some books about holography, I was looking for Kodark 649F plate but I haven't got one even until today! Before the introduction of Internet, looking for accurate information was difficult and time consuming unless you had a Ph.D degree and knew where and how to find that. Geting a laser was another huge obstacle for me in 1990s. So what I could do was learning optics theory and looking for textbooks of holography. (To be continued)

jsfisher · Post by **jsfisher** » Fri Jan 31, 2014 4:05 pm

Please tell us some details of your color setup. Pictures would make it even better.

unixboy · Post by **unixboy** » Fri Jan 31, 2014 4:15 pm

It is Denisyuk type reflection hologram. So the configuration of light path is very simple. The trick is to bind all laser beams accurately and passing the combined laser beam through the correct size of pinpoint in spacial filter. The angle of expanded laser beam is wavelength dependent and you have to find a best pinpoint for the spacial filter.

unixboy · Post by **unixboy** » Sat Feb 01, 2014 7:45 am

This is a small color Denisyuk hologram I made. Content: A long-life Star (Lao Shou Xing, Chinese god for long lifespan).

unixboy · Post by **unixboy** » Tue Feb 04, 2014 11:47 am

"Wishes for your fortune"

unixboy · Post by **unixboy** » Tue Feb 04, 2014 11:50 am

"Wishes for your fortune"

unixboy · Post by **unixboy** » Tue Feb 04, 2014 11:51 am

Wishes for your fortune

Holomark · Post by **Holomark** » Tue Feb 04, 2014 1:46 pm

Those look like some nice holograms

unixboy wrote: The angle of expanded laser beam is wavelength dependent and you have to find a best pinpoint for the spacial filter

I am just starting to work with two colors. I am interested in your statement about the relationship between the wavelength and the angle of the expanded beam. Can you elaborate? With my initial setup the divergence of the two beams is not the same and the result was that the replay lighting must be placed at a precise angle to replay both colors. Also it appears that the angle of the replay lighting is not the same as the angle of my reference beam.

unixboy · Post by **unixboy** » Tue Feb 04, 2014 2:17 pm

holomark wrote:Those look like some nice holograms
unixboy wrote: The angle of expanded laser beam is wavelength dependent and you have to find a best pinpoint for the spacial filter
I am just starting to work with two colors. I am interested in your statement about the relationship between the wavelength and the angle of the expanded beam. Can you elaborate? With my initial setup the divergence of the two beams is not the same and the result was that the replay lighting must be placed at a precise angle to replay both colors. Also it appears that the angle of the replay lighting is not the same as the angle of my reference beam.

Hi, holomark, because the beam needs to pass through the focusing lens before passing through the pinpoint, and the focal length of any specific lens is actually wavelength dependent even if it is a so called achromatic one. So the accurate focal points of Red, Green, Blue lasers are not in a mathematical single point. For any specific position of pinpoint, where close to the focal point, the expanded laser beams show different profiles after passing through the spacial filter. This is a common problem of differences between reality and theory.
For the latter part of your post, what type of hologram is that? reflection or transmission? For reflection one, if the replay angle is different from that of recording, it means the shrinkage of emulsion happened during chemical processing.