My first DCG... some help please!

holo_cyware · Post by **holo_cyware** » Tue Sep 22, 2009 8:37 pm

Thanks for the imput.

I managed to find a beter gelatine (claimed 220 bloom, I called the company to get the figure). I just coated some 2.5x2.5 plates, and we'll see the results.

As I have potassium metabisulphite that's what I use to reduce chromium 6+ to Cr3+. I'm perfectly aware of the risks involved when working with Cr6+ compounds.

JohnFP · Post by **JohnFP** » Wed Sep 23, 2009 9:44 am

That's very good. I didn't mean to sound like a preacher with the stuff, I just didn't know your levels of understanding of CrVI. And if someone cannot get a reducer or fixer then I just wanted to point it out. Just tryin to look out for a fellow holographer.

Hey, I wonder if you coat with KDi and then used the Potassium Metabisulfite as a fixer (reducer) if it would work??? Jeff pointed out in doing his G304 research that it is the reducing agent that is the most important for fixing and not the hardener. And the rest of the stuff in fixer does basically nothing. You could try it. If you can get some alum, throw a little of that in there just to bring the hardenss up a bit and you will have your home made fixer (adjust alum - more if milky hologram, less if narrow band and blue (no finge expansion in water)). You may find a nice combination that works for you.

holo_cyware · Post by **holo_cyware** » Thu Sep 24, 2009 6:27 am

Finally success! It felt sooo good to see it appearing.

Specs:
-220 bloom gelatine, standard mix (12

3)
-*very* crapy coating. Gotta learn this properly
-10 minutes exposure (80 mW Bremlas 532nm, spread to 20 cm diam.)
-5 minutes dark reaction
-1 minute hardening under 100W frosted lightbulb
-2 IPA baths (80% - 100%; 20 secs each)
-5 mins of drying (hair dryer)

No holotable, no spatial filter (just a lens).

JohnFP · Post by **JohnFP** » Thu Sep 24, 2009 10:23 am

---Jumping up and down with arms flailing---
Yeaaaaaaaaa!!!!

Nice job.

Dutchelm05 · Post by **Dutchelm05** » Thu Sep 24, 2009 2:14 pm

Congrads once you get a toe hold on this you can make improvements.
Good luck and continued success!

Joe Farina · Post by **Joe Farina** » Thu Sep 24, 2009 3:24 pm

Well done. It takes some practice to make good coatings, I wouldn't worry too much about it for now. I would experiment with the post-exposure processing methods a little (and also vary exposure times). I would juggle these items around: exposure time, dark reaction period, and light bulb fixing. If your gelatin is fairly hard, you may not have to use the light bulb at all. If they come out milky again, you can use the light bulb.

Also, I would concentrate on making a lot of plates, and storing them in airtight containers in the refrigerator. Then you can keep them for a long time, and make exposures whenever you feel like it.

Joe Farina · Post by **Joe Farina** » Thu Sep 24, 2009 3:32 pm

I forgot to ask, you're not swelling or washing in water before the alcohols?

holo_cyware · Post by **holo_cyware** » Thu Sep 24, 2009 3:58 pm

Thanks for the advices;

I did wash the plate in cold water just after the lightbulb fixeng, "till the yellow was gone", but I forget to mention it.

Dutchelm05 · Post by **Dutchelm05** » Thu Sep 24, 2009 4:04 pm

Joe Farina wrote:dark reaction period

Joe what is your experience with Dark Reaction?
What do you see in the outcome if DR is 0 vs 5 minutes?

Joe Farina · Post by **Joe Farina** » Thu Sep 24, 2009 4:19 pm

Hey Tony. Even with low dichromate levels, it does have an effect. The longer dark reaction, the more reduction and hardening will take place. The only reason I didn't use it more was because I was impatient

Since Cy is using more dichromate, the effect might be more pronounced.