First DCG, Please, Help me find the problem.

Kiffdino · Post by **Kiffdino** » Mon Jan 19, 2009 2:59 pm

so milkyness is a result of the gelatin softening up?
Maybe my baking process after development was too intense 2minutes at 100°C might have hardened the gelatin extremely.

jeff-blyth · Post by **jeff-blyth** » Mon Jan 19, 2009 4:50 pm

Kiffdino wrote:so milkyness is a result of the gelatin softening up?
Maybe my baking process after development was too intense 2minutes at 100°C might have hardened the gelatin extremely.

Hi Kiffdino, I just want to back up what Hans said, and take it even further. You have GOT to get that milkiness effect initially somewhere on the plate, normally that would be on the least exposed parts.
So if the gelatin is too hard by the normal standards , I suggest you cut one plate up for getting water temperature right . Put the first bit into really hot water
lets say for example your water temp is 80 C. Then do the alcohol processing . The result should be milkiness to such an extent that it is a "white out". So then do another piece at say 60 C , and after that another at say 40C . As you progress down to the point where the milkiness is less extreme you should start seeing diffraction colors buried in your milkiness. --Then you are getting somewhere, ------unless of course you very unluckily have no fringes recorded in the first place. But as things stand at the moment without getting any milkiness the secrets of what you have got there will remain hidden in your gelatin.
jeff

info.crew · Post by **info.crew** » Mon Jan 19, 2009 5:08 pm

Hi,
I had a similar problem with trying to expose DCG plates. I started from the second end. I tried the very long time, approx 0,5 hour and went down with time. I also do not use the oven, because this step has bad repeatability. I use the souliton of pyrosulphate/alum instead of hardener. my laser has 50 mw and I use the time about 40 min, so try 20 minutes and lay down the plate onto a subject for testing.
You can see it here
http://holographyforum.org/phpBB2/viewt ... f=4&t=6308
here
http://holographyforum.org/phpBB2/viewt ... &sk=t&sd=a
and here
http://holographyforum.org/phpBB2/viewt ... =20&t=6339

Kiffdino · Post by **Kiffdino** » Tue Jan 20, 2009 6:57 pm

Hi guys,
i did what you said
split the old plate (that one i exposed for 160 sec) in 2 pieces
and put the first piece in a 40°C water bath for 6 min then alcohol 70/90/99
got almost no milkyness on that one. But when i dried it there was some holographic glowing. the glowing was very close to edge impossible to photograph because it was to0 weak and it wasnt the object i recorded but rather some parallel stripes glowing in rainbow colors.
second piece i put in 60°C water then alcohol. same proceedure.
got defenetly some milkyness on that one but no hologram, only those rainbow colors again close to the edge.
today morning i coated some glas, in an hour theyll be ready to sensetize.
im gonna expose them like last time but this time ill reduce the baking time to about 1 min.
I guess that wont harden the gelatin that much.

JohnFP · Post by **JohnFP** » Wed Jan 21, 2009 4:12 pm

only those rainbow colors again close to the edge

That is from internal reflection of the beam entering the edge of the glass. Use some black tape on the leading edge of the plate to keep the light from entering the edge of the glass.

But with that said, it seems your processing is ok because you got colors from fringes but it may be you are not letting your plate settle long enough. Let it settle for at least 15 minutes to stablize from environment and movement.

Kiffdino · Post by **Kiffdino** » Wed Jan 21, 2009 11:24 pm

yeah guys, i got my first DCG holograms !!!
they are far from perfect but hey still a massive improvment from my last plates

this time i got massive milkyness, actually the plates looked like i dipped them in snow
Objects this time was coins (keep it simple)

so here is what i did:
-woke up early in the morning and coated glass for the evening (again veil coating)
-waited 12 hours for drying and then i sentesized with G307
-let the plates dry for an hour (this time no force dry as Dave recomended)

-took the first plate, mounted it, let the table settle for 10 min, 20 sec exposure, 5 min dark reaction
-put it in the oven for 1 minute ( cause i thaught i had baked too long last time)
-cooldown for a minute
-put the plate wash bath one for 3 min ( 32°C) second bath (35°C) for 3 min ( I actually aimed for the 27 Hans recommended)
oops, gelatin came off there was nothing left on that glass, well bad luck, next try

-took the second plate, mounted it, let the table settle for 10 min, 20 sec exposure, 5 min dark reaction
-put it again in the oven for 1 minute
-cooldown a minute
-put the plate in two washbaths (3 min + 3min), this time at room temperature so 19°C
-immediatly in alcohol bath 70% for 15sec then 90% for 15 seconds then into ALMOST BOILING (took the pot right of the stove) alcohol 99% -was that too hot?

The result was total milkyness after about 5 seconds into the last 99% alcohol bath the plate turned completely white.
But to my amazement after drying for about a minute with the paint-remover-dryer there was a hologram, its not visible in the picture cause its to feable but its there.

-well i thaught last try, with the third plate, again mounting , settling 10 min, expose 20 sec, dark 5min
-but this time 2 minutes in the oven
-cooldown for one minute
- again put the plate in two washbaths (3 min + 3min), room temperature so 19°C
-alcohol 70 for 15 sec / 90 for 15 sec/ 99 for 2 minute (this time a little less then boiling)
-again drying

The result was way better, the milkyness was less, and the hologram much stronger. You can actually see more then just one coin. even on the picture.

my conclusion:
Well, i think the major difference to last time was the fresh gelatin (12 hours old instead of 3 days waiting between coating and sensetization. And no force drying.
The only other variable i changed was the baking time. So my guess is i have to further increase it. Maybe 3 min.
After all thats what Jeff said on the DCG wiki:
"I have found that for a 4x5 plate 2 minutes is a good starting point. Depending on hardness of gelatin and exposure energy you may need to adjust this time. If the plates come out milky, increase the time. For the brightest hologram keep the baking time as low as possible without the plate coming out milky. "

Thanks again for all your useful coments

Kiffdino · Post by **Kiffdino** » Wed Jan 21, 2009 11:36 pm

the pictures:

Danny Bee · Post by **Danny Bee** » Thu Jan 22, 2009 1:07 am

Kiffdino wrote:the pictures:

you are very close, can you give information on laser?mw? size of beam spread at the plate? your gel mix? and type of gel bloom? trying to determan if its exposer or processing

Solarenemy · Post by **Solarenemy** » Thu Jan 22, 2009 1:13 am

I have yet to try DCG. I am waiting to get a good greenie laser. But from what I have read as well as this from the wiki, it says that all chemicals should be at room temp. There also should be a fixer step before the dehydration steps. Below came straight from the wiki and it seems very straight forward.

All temperatures can be at room temperature (70F). Take the plate and put it in Kodak Rapid Fixer with hardener. The Fixer should be mixed as per the instructions for the most dilute mixture (paper 1:7). Gently rock the tray until all yellow is gone then an additional 15 seconds. This should take anywhere from ½ minute to 2 minutes. I use a white tray to observe the yellow more easily. Once this is completed, place the plate in running water for 5 minutes ( a tray of water can be used if running water is not available). I now turn on a quartz halogen light that shines on the spot where I will lean the hologram to blow it dry. Then take the plate and place it in 35% alcohol for 15 seconds. Then 70% alcohol for 15 seconds, then 91% alcohol for 15 seconds then finally 100% alcohol until diffraction is visible (anywhere from 15 seconds to two minutes or longer). As soon as diffraction (colors) is seen allow another 15 seconds in that bath. Then take the plate out and lean it against the wall in the overhead light. With practice you will find which angle the diffraction is seen in the light and which way that relates to the visibility of the hologram when blow drying it. As soon as you lean the plate against the wall begin blow drying it with a hair dryer set on its hottest and strongest settings. Blow dry very close to the plate. Start at the center and in a circular motion move to the outside of the plate and repeat often. If the plate is leaning the right way the diffraction and image should start to get really bright. Continue drying until hologram in completely dry. You cannot over dry but you can under dry. This usually takes me 5 minutes minimum.

The rest of your process seems text book although heat stripping guns can reach a few thousand degrees on their output so I would think that might be too hot even for a few minutes. I plan to use one of those small ceramic heaters that has forced air. it only reaches 140 f at its output but should dry easily. It will dry my PFG-01 plates in about 45 minutes. Plus it heats the entire plate evenly.

I've not seen any processes that mention heating the alcohol. Plus considering it's volatility I would think that not to safe even if heated electrically. Just some input from what I have read and researched for my own us so far.

dave battin · Post by **dave battin** » Thu Jan 22, 2009 3:44 am

Kiffdino, are you heating and cooling you holograms on marble or steel plates? i found out very early on, this step is critical, I believe john even wrote this into the wiki process. John?

I see the center of your holo starting to get there, even cooling and even heating will help this. If you cut the plate in two and process one piece first and see brightness in the center, this will tell you to control the heating cooling better ...........