Monochrome and Color Denisyuk Holograms from China

Jem · Post by **Jem** » Tue Mar 18, 2014 6:15 am

Also, you can always mention them again on the Facebook Holography group?

www.facebook.com/groups/holography

unixboy · Post by **unixboy** » Fri Mar 21, 2014 7:53 am

Hello, it has been quite a while since my ebay (HongKong) account was suspended and I decided to build my own online store. I am quite familiar with Linux and simple PHP programming but it turned out to be a big work for me to build a secure https protocol online store. During these days, I learned many things of https and certificates just as I was learning holography many years ago. There are a lot of fun in such things. However, in order to spend more time on holography so I decide to use a commercial available platform named http://www.aliexpress.com to sell my silver halide holographic plates just for now. This is an ebay-like international e-commerce platform based on mainland China (The company web is http://www.alibaba.com) but for western customers. You might already know this company as they set for U.S. IPO recently. See http://www.usatoday.com/story/money/mar ... o/6487383/

5 pieces of AgX plates:
http://www.aliexpress.com/item/5-pieces ... 04930.html

10 pieces of AgX plates:
http://www.aliexpress.com/item/10-piece ... 98658.html

20 pieces of AgX plates:
http://www.aliexpress.com/item/20-piece ... 19511.html

BTW, please click my Chinese website www.3d-holo-art.com to show your location on the visitor's map. I will add English there later. Thanks.

lobaz · Post by **lobaz** » Sat Mar 22, 2014 8:08 am

Great! Do you use these plates for green & color holograms as well?

unixboy · Post by **unixboy** » Sat Mar 22, 2014 8:18 am

lobaz wrote:Great! Do you use these plates for green & color holograms as well?

Yes, I use those plates for green and color holograms. AgX has intrinsic sensitivity in blue and green spectra but needs sensitization in red spectrum. You only need to expose higher energy for green (532nm, 5800 micro Joul per cm^2) than red (633nm, 660 micro Joul per cm^2). A very detailed user instruction containing processing formulas and suggestions is included with order of plates.

unixboy · Post by **unixboy** » Mon Mar 24, 2014 12:37 am

I was hoping to sell my holograms but many people are interested in holographic plates. So let me introduce more about my experience in AgX plates. I began to know the holographic plate as "Kodak 649F" from 1970s-1980s publications but I had never seen it. Many years later, my direct experience of holography was with Slavich emulsions: PFG-01M, VRP-M, PFG-03M, PFG-03C and PFG-04 (DCG) since 2006. I had tried all types of Slavich emulsions and spent about $800 for all those materials. My "study" of holography in the dark room was slow until I saw the famous book of Dr. Hans Bjelkhagen : "Silver-Halide Recording materials for Holography and Their Processing". (The 1st edition was published in 1995 and it has 2nd edition now. You can find 2nd edition in Amazon. ISBN-10: 3540586199 or ISBN-13: 978-3540586197). Holography is a cross science of optics, material science, art and so on. After finding that one of my interest, chemistry plays a such important role in holography, I began collecting chemistry books of photography. There are many old AgX books in English, Chinese and Russian. Since the coming of the digital era in 2000, those books are usually kept in the library and nobody wants to read them. When I check out those books out of the library, I noticed the yellow pages of those books much older than me. Some old books are available from online book dealers and many of them are so cheap that I wonder the paper of the books are worth more than the book prices. Beside the old books, I also look for modern books and online PDF papers. Here is a contemporary book of AgX by Japanese scientist Tadaaki Tani: "Photographic Science: Advances in Nanoparticles, J-Aggregates, Dye-Sensitization, and Organic Devices" (ISBN 978-0-19-957295-3). For book of photopolymers, I recommend "Processes in photoreactive polymeres" edited by V.V.Krongauz and A.D. Trifunac. (published in 1995, ISBN 0-412-98401-6). For color holography, I recommend the book "Ultra-realistic imaging, advanced techniques in anaologue and digital colour holography" by Dr. Hans Bjelkhagen and Dr. Brotherton-Ratcliffe. (ISBN-10: 1439827990 or ISBN-13: 978-14398279940) .
I just ordered the bundle books offered by Ed Wesly in Amazon.
Books are good stuff and we can learn a lot. For making your own plates, I suggest you read the books I recommend and also find the discussions in this forum. There are many good threads in the archive of this forum.

unixboy · Post by **unixboy** » Mon Mar 24, 2014 11:52 pm

Good news for collection of Holography literature. SPIE is now offering 20% off on Milestones Series. Among those, at least 4 books are holography related.

Selected Papers on Fundamental Techniques in Holography
http://spie.org/Publications/Book/436130

Selected Papers on Holographic Interferometry: Applications
http://spie.org/Publications/Book/434950

Selected Papers on Three-Dimensional Displays
http://spie.org/Publications/Book/381006

Selected Papers on Holographic Recording Materials
http://spie.org/Publications/Book/2030012

Sale ends 31 March.
I already have 3 books of milestones.

unixboy · Post by **unixboy** » Fri May 23, 2014 12:21 pm

Time goes fast! I have been doing a lot of experiments to improve the diffraction efficiency of color holograms. I tried many different organic reductants as developer and modified the well-known PBU bleaches and all optical and chemical parameters that I can change. I think I have reached the maximum diffraction efficiency in my knowledge and ability. So it is time to work on my online store. It should be ready soon.
Now I am in China and far from UK and US. I had seen the video of color holograms made from Ultimate plates by Gentet. But why Gentet's color holograms lack the middle color between Red and Green (i.e. orange), purple and brown. It looks like bright red, green and blue but lacks other color. I would like to see the pictures of those very bright color holograms in display or exhibition (showing the hologram brightness and the background environment as comparison) now in UK or Europe. Can anybody help?

dannybee · Post by **dannybee** » Tue May 27, 2014 8:26 am

after seeing Ultima plates up close ... they are no more brighter then other color holograms I've see, brightness to the human eye is a very relative term. most of the photo you see of color Holograms have been lit with leds .. and look bright only under selective lighting. if you can make a good red plate with tight grain like the Russian Plates .. making it pan sensitive is a piece of cake

unixboy · Post by **unixboy** » Tue May 27, 2014 10:44 am

Hi, Dannybee, what I am concerning most is not making panchromatic emulsion but to increase the diffraction efficiency. Full color holograms are different from monochromatic holograms in many aspects.

A good full color hologram should have : high diffraction efficiency, correct reconstruction wavelength and narrow spectrum width for good color saturation, low noise i.e. low AgX grain size to reduce the light scattering.

High diffraction efficiency: like the multiple exposed holograms, the diffraction efficiency of full color holograms is proportional to 1/n^2, while n is the number of exposures (the number of exposures in multiple exposed monochromatic holograms or the number of different color lasers in full color holograms). The higher the number n, the lower the final diffraction efficiency of the holograms.

Correct reconstruction wavelength and narrow spectrum width: This means that no shrinkage of the emulsion should happen after processing. Also, no grain size growth should happen. Colloidal silver or different size distribution of AgX crystals will give broader spectrum width and thus it greatly decreases the color saturation.

Low noise: No AgX grain size growth should happen during developing and bleaching. If the developer solution contains AgX solvent, then AgX crystal will grow during processing as growth in Ostwald ripening. Actually, many organic reductants are AgX solvents.

Dinesh · Post by **Dinesh** » Thu May 29, 2014 12:56 pm

unixboy wrote:the diffraction efficiency of full color holograms is proportional to 1/n^2,

Why? And also, the diffraction efficiency of which component. The total brightness of a hologram is the sum of the scotopic function at some wavelength multiplied by the intensity at that wavelength.

B(lambda) = I(lambda)*S(lambda).

But, I(lambda) = eta(Lambda)*I(0)(lambda)

where S(lambda) is the scotopic function, eta(lambda) is the efficiency of the hologram at wavelength lambda and I(0) is the intensity of the reconstruction wavelength of the hologram at some lambda. So, the brightness of a hologram in terms of the efficiency of the hologram is given by

B = [SUM]{S(lambda)*I(0)(lambda)*eta(lambda)} (SUM taken over all lambda, if there is significant bandwidth, the sum converts to an integral over the range of lambda)

So, to relate the brightness of a full colour hologram to the efficiency of the hologram, the efficiency must be given for each wavelength component in the hologram. However, there is a calculation by John Caulfield (I believe) that states the if you record n holograms on the same medium with the same wavelength, then the efficiency of the final hologram is 1/n^2, where n is the efficiency of just one recording, assuming that all the recordings are independant. Thus, if you shot an H2 with, say, 5 H1s all perfectly exposed and developed, then the final hologram has an efficiency of 1/25th of the hologram if you only used 1 H1. That is, the more holograms you superimpose, with the same wavelength, the faster the final hologram efficiency drops. There are some problems with Caulfield's analysis, but his analysis was made in the 60s, when holograms were not generally bleached. So, the analysis works for unbleached holograms. It breaks down if you bleach the hologram.

unixboy wrote:Colloidal silver or different size distribution of AgX crystals will give broader spectrum width and thus it greatly decreases the color saturation.

The colour saturation is the proportion of a primary colour to the overall colour (S = Chroma/Lightness*). Therefore, I would think that the colour saturation would depend on the bandwidth of each component as a ration of the sum of the bandwidths of all the components. That is, by the Fourier coefficiant of one of the primaries to the sum of all the components. I don't think this has anything to do with the crystal size, assuming that te crystal size is small enough to record the appropriate spatial frequencies for the different wavelength components. If the crystal are too large to record the spatial frequencies, on average, then there will be no recording at all.

By the way, Danny brought one of your holograms to PCGG4. It was pretty good. Danny compared your hologram to my full colour holograms and the opinion was that the brightness was about the same (Danny's conclusion, not mine!). Mine were made on Colourholographics pan material, which he (unfortunately) no longer makes. I'm finding it very difficult to use PFG-03C. Danny has left me with some dye, so I'm going to try the experiment he suggests, put the dye into a fine-grain Slavich material and shoot full colour.

*Principles of Color Technology" by Billmeyer and Saltzmann p.23