My latest Denisyuk DCG

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Steven

My latest Denisyuk DCG

Post by Steven »

My latest Denisyuk DCG.

5"x7" mould coated with 240 bloom gelatin.
Dip sensitized for 1 minute in 3% sol AmDi.
Air dried for 24 hours, then exposed at approximately 200mJ/cm² at Brewster's angle using a 315M-100.
Left for two days dark reaction before processing.

Processed for 90 seconds with rapid agitation in Kodak rapid fix at ambient.
Washed in cold running tap water for 10 minutes.
Swelling bath temperature 40C.
Placed in wetting agent bath set at 38C and allowed temperature to drop down to 30C before placing in first IPA bath.
First IPA bath 60% (v/v), 20 minutes at 30C, with rapid agitation for the first two minutes.
Last IPA bath 100%, 10 minutes at 28C, with rapid agitation for the first two minutes.
Dried with my magic hairdryer :)

Photos shot with web cam. Hologram illuminated with a warm white 3 Watt LED, placed at Brewster's angle approximately 20 inches from the centre of the hologram. The hologram has some good burn-in and good DE. You can't see your hand through it when viewed in sun light. It's so bright, it makes my eyes water.
There is a bit of blue scattering, particularly around some of the marbles though.
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Joe Farina
Posts: 804
Joined: Wed Jan 07, 2015 2:10 pm

My latest Denisyuk DCG

Post by Joe Farina »

Very nice indeed, Steven, congratulations. Thanks for clearly detailing the processing steps, your technique is interesting. The image is crisp and "hard," real-looking rather than ghostly. The reconstruction looks quite narrowband and close to the recording wavelength. Those qualities are especially sought after in color DCG. If you're doing single-wavelength holograms of shallow objects, the broadband regime would be nice also. It looks like the long dark reaction was of some benefit.
Steven

My latest Denisyuk DCG

Post by Steven »

Joe Farina wrote:Very nice indeed, Steven, congratulations. Thanks for clearly detailing the processing steps, your technique is interesting. The image is crisp and "hard," real-looking rather than ghostly. The reconstruction looks quite narrowband and close to the recording wavelength. Those qualities are especially sought after in color DCG. If you're doing single-wavelength holograms of shallow objects, the broadband regime would be nice also. It looks like the long dark reaction was of some benefit.
Many thanks for your comments Joe.
A bit of explanation, re my process. The swelling bath consists of a 3ltr deep fat fryer, water pump, temperature sensor, photo developing tray and a PID temperature controller, the latter powers the deep fat fryer. In all the system holds about a gallon (UK) of water, so I don't put wetting agent in it. Besides, it would just make lots of bubbles :) Heated water from the fryer is pumped up to the photo developing tray (containing the hologram) and flows back over the edge of the tilted tray into the deep fat fryer. It's a bit Heath Robinson, but it works very well. The only thermometers I need to use are for the other photo developing tray containing the DI water with wetting agent and the IPA baths in clip&lock containers.

Yes, the hologram is quite narrow band and crisp, which was what I was aiming for. The camera doesn't do it justice.
It also helps to have small diameter reconstructing light source. The 3 Watt LED is quite good in that respect, but it's not very bright.
The depth of the hologram is about 3/4" or so. I have made relatively broadband holograms using this fixture, but it results in more colour dispersion.
I like my holograms to be crisp and clear so that fine details can be seen, even at the cost of brightness.

"Those qualities are especially sought after in color DCG"
That's my aim and I'm working on it :)
holomaker
Posts: 772
Joined: Wed Jan 07, 2015 8:01 am

My latest Denisyuk DCG

Post by holomaker »

Sweet Job Steven ! keep up the great work, why buy film when you can make it in lab ! :D
Steven

My latest Denisyuk DCG

Post by Steven »

holomaker wrote:Sweet Job Steven ! keep up the great work, why buy film when you can make it in lab ! :D
Thanks Dave.
Besides, film can be a bit of a pain to work with, index matching fluid and all that.

Steven.
Kiffdino

My latest Denisyuk DCG

Post by Kiffdino »

Very nice. Keep going ! More DCG Holograms, thats what we need.
Steven

My latest Denisyuk DCG

Post by Steven »

Kiffdino wrote:Very nice. Keep going ! More DCG Holograms, thats what we need.
Many thanks kiffdino.
It's getting closer to Christmas, so there are plenty more to be made.

Steven.
Sergio
Posts: 101
Joined: Tue Jan 20, 2015 12:25 pm

My latest Denisyuk DCG

Post by Sergio »

Super super! Congratulations!!

Have you any idea about the thickness of emulsion?

I think you can control the blue haze with the size of voids inside the hologram due the scattering. I found similar optimum, thickness for these bright holograms 15 um in photopolymer Darol emulsions. It is necessary find in practice, too much factors in theory.

Sergio.
Steven

My latest Denisyuk DCG

Post by Steven »

Sergio wrote:Super super! Congratulations!!

Have you any idea about the thickness of emulsion?

I think you can control the blue haze with the size of voids inside the hologram due the scattering. I found similar optimum, thickness for these bright holograms 15 um in photopolymer Darol emulsions. It is necessary find in practice, too much factors in theory.

Sergio.
Thank you Sergio.

I think that the emulsion thickness will be about 8.5µm - 9µm when fully dry.
I'm using mould coating with 56µm shims and a 15% gelatin/water mix.

The blue haze seems to be more noticeable around bright specular objects and down the edges of the plate.
I suspect that the later may be caused by some refraction within the adhesive.
I coat the top edge of the glass on the finished hologram with black nail varnish, so the light is not getting in there.

The blue haze is reduced/disappears when the illuminating light source is more towards a normal incidence rather than at Brewster's.

I will recheck my next hologram before sealing to see if the adhesive is the cause.

I'm using this stuff to seal my holograms:
http://www.go-araldite.com/products/epo ... x15ml-tube

I have been doing DCG for about a year now, so I still have much to learn, but I'm getting there :)
Sergio
Posts: 101
Joined: Tue Jan 20, 2015 12:25 pm

Re: My latest Denisyuk DCG

Post by Sergio »

Thank you for the Araldite info Steve, it is useful for DCG and maybe also for photopolymers.

Blue haze may be correlated to the Araldite high molecular weight, that for me seems improbable, or the vesicles onto DCG non exposed areas that seems to be amplified without fringes.
The blue haze is reduced/disappears when the illuminating light source is more towards a normal incidence rather than at Brewster's> This is related to more vesicles being illuminated and not filtered onto normal, maybe the vesicles are oval shape at inter-fringe space.

Sergio.



Steven wrote:
Sergio wrote:Super super! Congratulations!!

Have you any idea about the thickness of emulsion?

I think you can control the blue haze with the size of voids inside the hologram due the scattering. I found similar optimum, thickness for these bright holograms 15 um in photopolymer Darol emulsions. It is necessary find in practice, too much factors in theory.

Sergio.
Thank you Sergio.

I think that the emulsion thickness will be about 8.5µm - 9µm when fully dry.
I'm using mould coating with 56µm shims and a 15% gelatin/water mix.

The blue haze seems to be more noticeable around bright specular objects and down the edges of the plate.
I suspect that the later may be caused by some refraction within the adhesive.
I coat the top edge of the glass on the finished hologram with black nail varnish, so the light is not getting in there.

The blue haze is reduced/disappears when the illuminating light source is more towards a normal incidence rather than at Brewster's.

I will recheck my next hologram before sealing to see if the adhesive is the cause.

I'm using this stuff to seal my holograms:
http://www.go-araldite.com/products/epo ... x15ml-tube

I have been doing DCG for about a year now, so I still have much to learn, but I'm getting there :)
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