stuck with DCG, always dim or foggy

Joe Farina · Post by **Joe Farina** » Thu Aug 05, 2010 2:54 pm

Really nice, Thieu, especially for one that's been reprocessed 20 times. If you're just doing tests, I would continue to use just a water bath (and vary the temperature) and a single bath or spray of 99+% IPA. That should give good broadband results, depending of course on the hardness of the gelatin and the temperature of the water bath (and any type of intial fixing with a light bulb or fixer). I've found that when using Knox gelatin, neither fixer nor light bulb is needed, if the plates are aged for a while in the refrigerator, and the water isn't too warm (and the IPA is cool).

This is the second DCG hologram I've seen made with the 445nm diode without banding :dance: Now in the gallery section, I've seen three more by Dave. Looks like you guys are on a roll :dance:

Thieu · Post by **Thieu** » Thu Aug 05, 2010 2:55 pm

I updated my profile, so it will be shown next to my name now too, but I live in the Netherlands. I got some IPA that I ordered online in a local webshop about a year or so ago, but judging from their website they no longer ship highly flammable liquids by mail. I'll check with them if they consider IPA highly flammable, cause it's a bit unclear from their website. And other larger stores do ship stuff like acetone and even ether by mail. But besides the shipping, what they charge for IPA is more than $10/liter, so that's another reason why I'd switch to something else if it works just as well. The stuff Martin uses can be bought at every supermarket here for less than $2 a liter.

Thieu · Post by **Thieu** » Thu Aug 05, 2010 8:44 pm

Guess I can officially declare myself no longer stuck (see gallery section

) Longer exposure and more hardening turned out to be the solution.

Martin · Post by **Martin** » Fri Aug 06, 2010 5:39 am

Thieu wrote:I read your post and thought, what the heck, I'll try the shock treatment you described with 99% IPA right after the water bath on the holograms I made yesterday that were better than the day before but not so bright either. It caused a *huge* increase in brightness:

The hologram has been processed 20+ times, so it has suffered quite a bit from that. And there's quite some fog. And one of the pegs moved. But no banding and the brightest one so far. I'm happy, thanks!

Glad to hear that, congratulations!

Regarding the 50/50% IPA etc. treatment I wonder how your previous holograms look like at 405nm (Bluray). Maybe your holograms have been shifted towards the UV???

I'll do some tests with the several varieties of denatured ethanol available here. It would be really great if I can find one that works. IPA has become quite hard to obtain.

Yes, absolutely. It's exactly the same here.

Thieu · Post by **Thieu** » Fri Aug 06, 2010 7:01 am

I did some ethanol shopping yesterday and bought two varieties. The first one was the stuff for cleaning windows, the blue stuff with quite an unpleasant smell. I believe it's denatured with 15% methanol and has pyridin in it. This stuff didn't work, it played havoc on the coating, damaged it in most places and created blotches with a huge blueshift.

The other stuff however, something that's used for indoor fireplaces etc., looked more promising, it didn't seem to cause further damage and it gave similar results to IPA on the damaged hologram. It's denatured differently and seemed to be almost odorless. But I need to test it on a good hologram to make a final conclusion. So I'll make some more plates with exactly the same parameters that I used yesterday that created the bright one, and develop one of them in this ethanol. I'll report what happened.

JohnFP · Post by **JohnFP** » Fri Aug 06, 2010 10:34 am

Thieu, very nice course of actions. Welcome to holography.

Martin, I am simply amazed that the spray bottle techinque works. I have always thought that it is most important to get a very uniform drying to keep the greenies down. Seems the spray bottle would start to dry little droplet spots before the rest of the plate was prayed. But the spray bottle technique disproves that. :think:

dave battin · Post by **dave battin** » Thu Aug 26, 2010 12:30 pm

Thieu was this hologram made using no optics on the diode, as just an expanding raw beam?

dave battin · Post by **dave battin** » Thu Aug 26, 2010 8:06 pm

here's a couple of shots of the raw beam, i have the output turned up so its not stable enough for holography (untill i get the tec hooked up)

im off on holoday to Canada ill be back mid week to start testing this ............... the beam sure looks promising!

Dutchelm05 · Post by **Dutchelm05** » Fri Aug 27, 2010 1:19 pm

Dave if you need any TECs let me know, I have a fair amount of several sizes.

Really impressive looking beam!!

Danny Bee · Post by **Danny Bee** » Fri Aug 27, 2010 2:50 pm

wow dave how in the world did you get the beam to do that good of a profile? im very impressed!!!!!!

This diode doide will open the doors of dcg to alot of new comers

with my 457nm I use a mix of 1.5/10/100
but this is a bit deeper blue 445 so I would try even lower that 1
maybe .8 to let more light threw.

or use the new CAB system to let more light hit the object

but the objective here is to get object and film plain as close to 1 to 1 for max brightness