First silver halide Polymita

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RaulBSP

First silver halide Polymita

Post by RaulBSP »

Hello
This night, i’ve made my very first silver halide hologram! :D :D :D
This is an endemic Cuban snail “Polymita”.
It was shot using DVD-writer laser, on BB640
plate.

Saludos,

Raúl.
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DJ Mathson

First silver halide Polymita

Post by DJ Mathson »

Congrats.

These tree snails are very beautiful. I found a web page about them:
http://www.geocities.com/Eureka/Gold/94 ... hompg.html

How is your diode laser configured?
RaulBSP

First silver halide Polymita

Post by RaulBSP »

This is a 100 mw laser but only 50 mw useful for holography.
I focus it through a pinhole (home made spatial filter), then
expanded using divergent lens. I use pinhole because diode
window is difficult to clean so I can´t use naturally divergent
laser beam. Removing diode window isn´t a viable solution for me too.
Saludos,

Raúl.
JohnFP

First silver halide Polymita

Post by JohnFP »

Congratulations! Very nice!
Sergio

First silver halide Polymita

Post by Sergio »

Very cool, I did not find anything about Polymita on Wikipedia or goggle.. have you a photo to compare with hologram?

-Unfortunately (or fortunately? ) only visiting Cuba we could see one... :wink:
glajciorz

First silver halide Polymita

Post by glajciorz »

Great Raul :D

Try painting black the backside of your holo to increase contrast.
Will you send a video to Youtube ?
How long did you expose ?
Did you use any presensitizing ?
What kind of bleach did you use ?
What is the viewing angle ?
What are your spatial filter parameters ?

greetings
Adam
RaulBSP

First silver halide Polymita

Post by RaulBSP »

This snail Polymita (I’ll send photo soon) can be found only in he north-eastern region of Cuba, where I was born. There is a natural sciences museum with a great collection of them. But recently I discovered that in Havana, they are indiscriminately sold by some people to tourists.
I tried to make an exposure of 0.15-0.30 mj/cm2, as required for these plates. So, I expanded beam to 25 cm diameter, and make a 3-5 sec exposure.
I presensitized in water with some dish washer, to solve possible plate desiccation.
TJ1 developer was used, and sulphuric-dichromate bleach.
Spatial filter was made with a cheap collimator lens from a laser pointer and a homemade pinhole made on aluminium foil using a needle. It was mounted in a homebrew mounting, so hole position can be adjusted. I have to recognize that no calculations where made on this. :oops: I just tried several times until got a reasonable beam quality.
I’ve shot a pair of other holos, but they are very dim, under the same conditions. I suspect on movement, due to poor quality of object and plate holder, or may be problem in reusing developer from plate to plate?
Colin Kaminski

First silver halide Polymita

Post by Colin Kaminski »

Hi Raul,

I found when making pinholes in foil that it worked best if I layered the foil to about 10 layers then made a pinhole. Usually I was able to find the right diameter in the 4th or 5th layer. I can't remember where I heard that tip but it worked pretty well.
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