G307 DCG woes

dave battin · Post by **dave battin** » Thu Dec 17, 2009 3:48 pm

emf wrote:I should be able to run a good series of tests this weekend. I'm sure I can get the plate movement under control, but maybe I should go back to a plate full of coins for the test shots.

yes this is your best strategy. eliminate as many variables as possible. rather than use the coins do you have any green Polaroid/poly holograms you can use to make contact copies, these will give you back the brightest results/shortest exposure times. the test hologram i used while testing was the enterprise hologram (blindingly bright when replayed with green laser light). attach your master hologram to a glass plate and then epoxy three BBs to locate the film plate onto (3 point kinetic mount), settle time was like 10 mins .........

again ill send you a mirror and then you can put all the optics a side and concentrate on making/processing film, i can also send you a green polymer hologram to make as a DCG test plate.

emf · Post by **emf** » Thu Dec 17, 2009 4:58 pm

Hm, I'm trying to think whether I have any other suitable idiot-proof objects. I guess I could always spray-paint some coins with a flat white paint. Cuphooks might work too.

I don't think I have any holograms for copying. Pretty much the only holograms I have (or indeed have ever seen) are embossed holograms. If those work, I can dig up an old national geographic or make a 3"x3" mosaic of visa cards.

Dave, I'll PM you my address -- I think that will be a big help in getting this figured out.

Dutchelm05 · Post by **Dutchelm05** » Fri Dec 18, 2009 6:43 pm

dave battin wrote:i can also send you a green polymer hologram to make as a DCG test plate

Hey Dave, Does the the polymer hologram need to be placed so that the pseudoscopic image is showing?
Thanks,
Tony

dave battin · Post by **dave battin** » Fri Dec 18, 2009 9:44 pm

Dutchelm05 wrote:
dave battin wrote:i can also send you a green polymer hologram to make as a DCG test plate
Hey Dave, Does the the polymer hologram need to be placed so that the pseudoscopic image is showing?
Thanks,
Tony

As long as the master hologram plays back nice and bright with the laser's light, it dosent really matter which way you record it...

emf · Post by **emf** » Tue Dec 22, 2009 3:13 pm

Made some good progress last night. This weekend I spent more time shoveling snow than making holograms, but I did get in some experimenting with a few different types of plate supports and made a few more holograms which came out about as well as earlier ones I had posted. I also spray-painted some coins white and did another uninspiring hologram of them.

Last night I figured I'd try an exposure test, so I wound up with this:

: Exposure test; IMG_6342.jpg (84.22 KiB) Viewed 2733 times

Exposure times, clockwise from the upper-left, are 20, 15, 10, and 5 minutes. The 15 minute exposure was the brightest -- whether that was because it's the right exposure or because something in the 20 minute exposure moved, I'm not sure -- but anyway, it was brighter than anything I had seen so far.

So I did a straight 15 minute exposure of the same setup and got my brightest hologram yet:

: White Pennies Dark; IMG_6357s.JPG (64.79 KiB) Viewed 2733 times

This one is finally bright enough I can take a picture of it with all of the lights on:

: White Pennies Light; IMG_6362s.JPG (78.23 KiB) Viewed 2733 times

It came out very red, and the edges of the hologram started to turn milky. There was no milkiness in the four-exposure test plate.

With these two holograms, I upped the temperatures a bit. The fixer was room temperature, and water was slightly warmer, maybe 70F. I placed the alcohol baths on a heating pad, so the first two were in the 80F range, with the final bath floating in the hot tap water at around 95F.

Dutchelm05 · Post by **Dutchelm05** » Tue Dec 22, 2009 4:18 pm

Wow great progress emf!
Looks like you are making great advances.
If these are indeed painted white the color is getting close. You film looks great!
The whitening can be cured by fixing a bit longer. Or the age of your film is too new.

I have a small suggestions; The 15 minute exposure seems really long. Perhaps too long for experimentation. If you include setting time and processing time you may not get only a half dozen shots a night without the aid of a lot of Red Bull.
Consider reducing your beam diameter to maybe double the size of a single coin. This will reduce your exposure time from 15 minutes to maybe a 1 or 2. You can take an energy reading on how much power you have now and with the smaller beam size take it again and can get a good ballpark figure on how much shorter it will take.
This will allow you to make lots of iterations and reduce the chances of movement. You could also cut you plates in four, and further increase output. I know this more work on your set up but I think in the long run you’ll be happier. At this point you need to understand relationships among all of the hundreds of variables. There is a DCG section somewhere in the forum that basically has the key variables, see if your process follows it.
Any way have fun with it and continued good luck.

dave battin · Post by **dave battin** » Tue Dec 22, 2009 4:28 pm

excellent progress Eric! how did you harden these? the last bath is the only one that need to be heated
( i microwave my 99.5 alc just prior to use). you need to really attack the plate with the hair dryer on full hot just as you pull it from the last hot bath ,it will go thru two or more changes as you heat it. now to really confuse your process scheme, you may reprocess your hologram starting with the water bath just prior to the ALC baths......... good luck and keep going. as you reprocess the holograms they seem to continuously shift towards the blue and the milkyness goes away too! have fun and keep us posted!

emf · Post by **emf** » Tue Dec 22, 2009 5:52 pm

Thanks for the encouragement! The coins are painted white, resting on black tile. They look like crap in person, but they turned out pretty well in the hologram. The film was about four days old. I've been doing about 3 plates per night, faster exposures would help a lot.

I'm still using the same non-rapid fixer as before. I couldn't find it locally, but I'm going to be passing though a few larger cities over Christmas so I'll try to snag some then. Re: fixer, if I leave the plate in the fixer past when it clears, will that just continue hardening or will it start to damage the image?
Tonight I'm just going to try to duplicate my modest successes, then I'll pick up after Christmas and start nailing down these variables.

ooleg · Post by **ooleg** » Wed Dec 23, 2009 7:54 am

Hi emf!
Until recently, I also conducted many experiments with g307 and 50mW, 532 nm. The only change in g307 was that I used AmDi, not KDi. Got results similar to yours - unsatisfactory. I concluded that the time of 20 minutes will make a good hologram coins, but it is pointless - if no coins are likely to have exposure to 1 hours. This is a very bad result for me!
I read that the addition of 1-2 ml isopropanol instead of glycerol improves the sensitivity much. I did not try - if you want to try - I will be interesting.

Today I invite you to try first pure DCG recipe with a laser diode of 405 nm. I do not know what you get ...

Joe Farina · Post by **Joe Farina** » Wed Dec 23, 2009 12:21 pm

For some reason, holographers on this forum haven't had good luck with G307. I've heard quite a few negatives, and hardly any positives.

It seems strange that the earlier system of TMG & green-sensitive dye has been overlooked. Considering the spectacular results achieved by Christiano Perucci (see his many photos on the forum and complete descriptions) with DCG/TMG & red-sensitive dye (MB) and a lower-powered HeNe, I assume exactly the same results are possible with a green-sensitive dye (see Jeff Blyth's paper in Applied Optics) using a lower-powered 532nm laser.

Is the problem the availability of TMG? I know it can be hard to get.

There are other sources of information on Jeff Blyth's dye-sensitized DCG. It used to be on his website, and I assume it's still there. Also, the comlete system was described in an issue of Holographics International (1989) which was available online, and probably still is (unfortunately I don't have a direct link). It was also published in SPIE 1212 (1990) pages 190-9. The Applied Optics paper (Vol. 30, No. 13, pages 1598-1602) gives all the details, including the type of green-sensitive dye (eosin Y). Still more information is available through the European Patent Office (espace.net) under UK patent GB2232263A.