G307 DCG woes

emf · Post by **emf** » Wed Dec 23, 2009 3:58 pm

I haven't given up on G307 yet. I did get a few holograms with 307 that came out as well as the ones I was getting with plain DCG at the time, and I'm planning on trying it again once I can get solid results with regular DCG. I do have a blu-ray diode and I've been following the thread on 405nm DCG, but the laser is one really big variable I don't want to mess with right now. I'll give it a try eventually.

The availability of TMG is a big factor for me, not being connected to any company or university. When I was looking through the recipes on the wiki and trying to figure out whether to stick with a red & do MBDCG or silver halide vs. buy a green laser and do DCG, the difficulty finding TMG, pinacyanol, and some of the other dyes made the decision pretty easy. I recently ran across a post mentioning using the obtainable Rhodamine B as a dye for silver halide, so I might have to try my hand at that.

Anyhoo.... I tried three more plates last night, identical in exposure & processing to the last one I posted. One came out looking very similar, the two considerably dimmer and more yellow-green-ish than red-ish. I'll give it another go in a few days.

Cristiano_Perrucci · Post by **Cristiano_Perrucci** » Wed Dec 23, 2009 5:09 pm

When dealing with low-power laser and extremly long exposure time, you MUST know how your holobench works. A quick look to the Mitchelson inteferometer is not representative. In order to get good Denysiuks I had to expose my plates from 10 up to 25 minutes. In holography a such long time is comparable to a geological period when mountains and oceans easily swaps.

What I whould suggest is to build a Mitchelson interferometer gluing the first mirror to the object and the second one to the plate; then make a exposure simulation recording with a digital camera a frame every 15 or 30 seconds. When finished enjoy the movie and make your considerations (beware to heart attacks!!).

Althought DCGs are very tollerant to vibrations, at least for Denysiuks, they could decrease image brigthness without interfering with image formation.

Talking about organic chemicals, I experienced the same problem. Go to http://www.acros.com and try to find a local distributor in your area that can sell to private person.

By the way, my "core business" now is Silver Halide Emulsion Making, I'm bored to sniff the nasty fumes of IPA!

Cristiano

Sergio · Post by **Sergio** » Wed Dec 23, 2009 8:04 pm

Cristiano_Perrucci wrote: What I whould suggest is to build a Mitchelson interferometer gluing the first mirror to the object and the second one to the plate; then make a exposure simulation recording with a digital camera a frame every 15 or 30 seconds. When finished enjoy the movie and make your considerations (beware to heart attacks!!).

Cristiano

This is absolutely outstanding. So you can make a gradient movement recording with temperature, pressure and humidity variation, also one could put the mirror over the naked film emulsion to verify the water absorption over time (one more variable to exclude, the Denisyuk fringe sensitivity is very high).

Sergio.

Cristiano_Perrucci · Post by **Cristiano_Perrucci** » Wed Dec 23, 2009 8:19 pm

I forgot to say that all my MBDCGs holograms were made using a glass sandwich, so that humidity were trapped between the two glasses.

Martin · Post by **Martin** » Thu Dec 24, 2009 11:39 am

Cristiano_Perrucci wrote:I forgot to say that all my MBDCGs holograms were made using a glass sandwich, so that humidity were trapped between the two glasses.

I see, thanks for sharing.
I was wondering about this for a quite a while. It sounds like an excellent approach for creating a stable "micro climate" within the recording layer.

Joe Farina · Post by **Joe Farina** » Thu Dec 24, 2009 12:26 pm

Thanks a lot for that information, Cristiano. On a historical note, I've attached an old 1971 paper from Applied Optics, with something similar to what you describe.

JohnFP · Post by **JohnFP** » Wed Jan 06, 2010 1:03 pm

What I whould suggest is to build a Mitchelson interferometer gluing the first mirror to the object and the second one to the plate; then make a exposure simulation recording with a digital camera a frame every 15 or 30 seconds. When finished enjoy the movie and make your considerations (beware to heart attacks!!).

Just add fringe locker and do resist...