Additional VRP-M + 315M results

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MichaelH

Additional VRP-M + 315M results

Post by MichaelH »

I've done a number of VRP-M tests with my new 315M and narrowed down the fog problems I was having to humidity attacked film. I still need to find a solution to the noise levels and have some hope that a different combination of dev & bleach will give me better results. I'm going to give the TJ1 developer a shot next.



I note that wler also experienced high fog levels with VRP-M but he didn't say what chemicals he was using.



The original post with larger pictures is available here.





After several days of tests I've gotten a couple of decent transmission holograms on VRP-M using a Coherent 315m.



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This first shot shows some objects which are 9" from the plate, sitting on the table. R2, Snoopy and Barad-dur models. Click on the image to see a larger version.



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The second shot shows an owl statue (20" from the plate), part of my collimating mount, the top of Barad-dur and a mirror which is reflecting an image of R2 and Snoopy which virtual image is 38" from the plate.



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The final shot is angled up some to show a reflection of the owl that was coming off the plate holder glass, for a total travel of 60". The owl reflection is just below and to the left of the bright spot at the top of the picture.



Unfortunately it turns out that the 8x10" package of film I've been using is nearly toast. I'm guessing that the exceptional humidity we had this spring and early summer got to it and that's what's causing the high fog levels I'm seeing after development.



I came to this conclusion after receiving a new package of 4x5" from Integraf and putting it in the same setup as show above. The image came out just as bright (except where I ended up with some movement *sigh*) and there was no fogginess of the film after removing it from the bleach. While somewhat noisy, that hologram wasn't nearly as noisy as prior tests.



I did find though that putting the foggy film through a post treatment of 2% ascorbic acid greatly increases contrast, just as it did with PFG-01 and removes the fog problem. So I can make use of the ruined film but I'll have to treat all the resulting holograms with ascorbic which I did somewhat rarely with PFG-01.



The hologram was exposed for 22 seconds, developed for 20 seconds in JD2, bleached in EDTA and post-treated with 2% ascorbic acid.
dave battin

Additional VRP-M + 315M results

Post by dave battin »

Nice job on the holograms Michael. It's fantastic to see the depth possible using this laser!
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