DCG Variation Question

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Dutchelm05

DCG Variation Question

Post by Dutchelm05 »

I was shooting this weekend and could help noticing how different each shoot is from session to session.
I hope there are still some DCG guys out there that can help me get a feel for this. Haven't heard much from Joe, John and Danny. Enen the beginners opinion would be helpful. But I will ask anyway.

If the set up is about the same (beam angle, intensity etc,) how much variability do fine when shooting DCG?
How many shots does it take to "dial" it in?
Once dialed if you say shot 10 plates how much in variabilty to you see?

Saturday I shot 10 plates,
1 did not come out at all, it was the last one and I must have been brain dead by then.
3 were really good.
3 had small signs of movement
3 looked fine and were good.

The difference between really good and great is big. Some just have that certain something perhaps a life of its own. Hard to discribe, but it is a lot like love, you know when you see it.

Thanks,
Tony
Joe Farina

DCG Variation Question

Post by Joe Farina »

Hi Tony. By now, you should probably have a better feel for DCG than me, but based on past experiences, I can only say that some days are good, and some are bad. Of course we all know that if all the variables are exactly the same, the result will always be the same :wink: But we also know that variables are never the same.

Over the many years I've been involved in holography, I've heard it said over and over again that the best way to make progress in lab work is to change one variable at a time, and observe the result. But I never follow that advice myself, because how can you really know that you've "locked down" all the other variables? It's not realistic advice. The key is to change many variables at once, and have enough acumen, experience, intuition (or whatever you want to call it) to sort out, identify, and extract something useful from that complex mixture of variables. It sounds difficult, but in practice is not that bad. If we just changed one variable at a time, progress would be incredibly slow.

But more specifically to your question, I would just try to get a better handle on the age of your film, temperature, and humidity in your lab, plus any other variables you can think of. In my lab, I took considerable pains to stabilize temperature and humidity. Any variations that you're aware of (or not aware of) can cause irregular results.
Dutchelm05

DCG Variation Question

Post by Dutchelm05 »

Joe Farina wrote:But more specifically to your question, I would just try to get a better handle on the age of your film, temperature, and humidity in your lab, plus any other variables you can think of. In my lab, I took considerable pains to stabilize temperature and humidity. Any variations that you're aware of (or not aware of) can cause irregular results.
Thanks Joe, good to hear from you.
This is a very true statement and I also strive for it. I think it is why the great DCGers live in New Mexico, Utah and planet Mercury. The humidity is low and it is easier to pump moisture and heat in then to cool and dry out.

This was exactly what I encounted Saturday in that I had to allow more time for my film to humidify which distrubed be since it was so far off the beaten path. Since I only have a few hours a week, time is not a resource so when I am ready to shoot, I hope everything falls in place.

Can I ask Joe about if you shot 10 plate what sort of variation you see?

All the best my friend,
Tony
Joe Farina

DCG Variation Question

Post by Joe Farina »

Dutchelm05 wrote:Can I ask Joe about if you shot 10 plate what sort of variation you see?
The problem is getting geared up. If I'm lucky enough to have have a full week available, then by day 7, I should be near 100%. But on day 1, it might be 0% (in terms of acceptable quality). I would say the #1 factor is the film batch (when and how it was made), then humidity, then temperature. Plus a host of other factors we all know about :wink:
dave battin

DCG Variation Question

Post by dave battin »

great thread ! i was just wondering how i would reply. shooting ten plates is an ambitious endeavor and i couldn’t think to shoot them all in one session. it is easy to use what i call "shot gun" approach, where you get the plates all ready to go and shoot shoot, and then count the good ones in the end...... now it is time to raise the level of the quality. like Joe did in getting environment stabilized. my filtering needed to be finer, and have now adjusted with improved results seen. Tony an immediate and easy improvement for you is it to stop that movement, thereby increasing your odds of a good dcg hologram.
i have now switched my mindset to making these "little pieces of gold"(the film plates) each one a precious monument, lets say i want to make four pieces, ill coat and prepare 6 plates, one is like a sacrificial to get my adjustments correct (ill cut it into 4 pieces) and make processing adjustments on each quarter, usually by the 3r quarter piece ive got it corrected, now that leaves me 5 plates to shoot, if i did good all these five will be acceptable even though i'm only going to shoot the first four with an extra left over incase of a screw up.
Dutchelm05

DCG Variation Question

Post by Dutchelm05 »

dave battin wrote:Tony an immediate and easy improvement for you is it to stop that movement, thereby increasing your odds of a good dcg hologram.
Ya shells are a bit difficult, the bottom is really thin.

So Dave your basiclly saying each session requires some tweaking based on evironmental conditions and the nature of the film. I think your approuch is valid and the right way to go. For me it is difficult to get everything just right as far as getting a coating run then shooting X amount of hours later. So I have to adjust my shooting whenever time permits.

I think for me the question is those holograms that are good compaired to those that are great. This is why I shot 10 in a row (although I must say it was pretty exhausting mantaining that level of concentration). Like I said 3 were really good, they just popped and drew me in. The others were shot (as far as I can see) the same way and processed the same way. I even have a data logger monitoring temparture and humidity. And it was not like the first three were great and the others not, it was more ramdom. Perhaps it is as subtle as a tiny bit of movement. And perhaps it is dumb luck :?
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dave battin

DCG Variation Question

Post by dave battin »

beautiful hologram Tony! the underlaying thing thing here is the movement. you need to eliminate it first to proceed. as the outher three shots could be they were 1/4 wave or less in movement,which could easily look as if it's shaded ...............
Dutchelm05

DCG Variation Question

Post by Dutchelm05 »

Yes you are right Dave. It is hard to seperate these things sometimes. :wall:
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