Dip-N-Shoot DCG film plates.

[jeff-blyth]

Too bad dichromates are usually yellow. We shoudn't forget that after all the safelight we use for DCG work is yellow too.

Jeff, how exactly your G307 works? I'm assuming that the glycerine expands the gelatin, then the alum kicks in "freezing" it in the gonflated state?

No your assumptions are probably incorrect. But Kaveh put all the full 2006 ISDH papers on his HOLOGRAPHER.org website.
My paper there (with John's contribution) goes into the mechanism of G307. If you sent me your email address I will send you the text only version as a WORD file . my address is:-

jeff at biotech dot cam dot ac dot yoo kay (hope this stops any mechanical web crawling programs.)
Jeff

[dave battin]

by JohnFP » Fri Mar 19, 2010 10:16 am
Dave, did you get the plates I sent you? I assume you are going to try the DnS with them too.

Yes John thanks I’ve received the plates and have started testing…

by Dutchelm05 » Fri Mar 19, 2010 11:54 am
Do you have a means to check thickness or do you simply rely on the mold coat?

No at this point I rely soley on the thickness of the shim and the gelatin/water ratios.

by Joe Farina » Sun Mar 21, 2010 10:00 am
That's interesting, but if the 405nm lasers have a coherence of only 2 or 3mm, it's kind of a moot point.

Joe, I am currently shooting 5x7 dcg (4 minuet exposures),contact copies with a short coherent length 473nm laser. If anyone would like to purchase one of these neat little lasers (@30mw+), just PM me for te details.

Thanks for the absorption chart on dichromate Jeff and Colin, yes it seems to be a very fine balance between the two ,absorption vs. sensitivity, Jeff your chart solve the differences john and I had , proving we both were kind of correct……….

[Joe Farina]

Joe, I am currently shooting 5x7 dcg (4 minuet exposures),contact copies with a short coherent length 473nm laser.

That's good, but contact copies are another ball of wax, as far as I'm concerned. After all, you do need to make the H1 first. It might be interesting to make a good, clean silver H1 and then do a contact copy in DCG. Dave, do you have a rough idea of the coherence length of the 473nm laser?

[dave battin]

It might be interesting to make a good, clean silver H1 and then do a contact copy in DCG. Dave, do you have a rough idea of the coherence length of the 473nm laser?

it seems to be a couple mm in coherent length, i was shoot a copy off glass sealed master with 1/8 glass........

Now you have your thinking cap on Joe! With a nice bright silver, dcg or poloymer hologram it is VERY easy to make copies, when i spend time to make a nice hologram if im shooting off a real object,it's always a crap shoot as far as movment. by make a nice dcg H2, i can now simply pull the master from the drawer put it on the table and be shooting in a 1/2 hour, shorter exposuer times too........


I have a few of these 473 nm lasers and i plan on doing multi/exposuer/color with two (or more) setups haveing different master and such ......

in my view making the sealed master is where all the work goes into,i got lucky as some of my lousey green masters suddenly became quite bright/clear in 473nm light.............


Another benefit to reduced Dichromate in the film (blue VS green sensitivity),is the savings in rapifd fix !

[JohnFP]

Jeff, do you happen to have the transmission chart also? It would be nice to see them site by site. I am pretty sure, as you stated, they would not be the conjugate of each other.

Jeff, I remember going to the Porcelain Cat Group meeting at Michael's. We were using Danny's 532 100Mw DPSS laser. The film I brough was not even close to being saturated, was 24 hours old, traveled by air from Baltimore to Texas (warm, cold, warmer). I believe it was about 2.5 - 3% AmDi. The set up was, the laser was on a dressing with a mirror stearing the beam down to the floor. The Plate was lying right on the object. I think the exposure was about 10 or 15 minutes. If I recall correctly, we got some pretty good holograms. This was an improvised set up to say the least. My biggest point here is, if you are doing 15 minute exposure and need to to to 20 (33% more), why not do that to allow the addional light to get to the diffusing object instead of loading up the plate. That's just my opinion and my recollection, but whatever works works.

Dave, with that much AmDi in the plate, are you using spill over lighting to get more lighting to the object. Or do you really not see fall off of brightess of the object with a standard SBR?

Thanks Danny, but it's is not hardware. And it's a little too personal to put on the forum. But again, thank you for offering.

[dave battin]

Dave, with that much AmDi in the plate, are you using spill over lighting to get more lighting to the object. Or do you really not see fall off of brightess of the object with a standard SBR?

not on these last holograms John, used only one little concave mirror to spread beam (for making the H2 also).


On a seperate note;

here is a shot of this cool little 473nm laser

[jeff-blyth]

Jeff, do you happen to have the transmission chart also? It would be nice to see them site by site. I am pretty sure, as you stated, they would not be the conjugate of each other.

Jeff, I remember going to the Porcelain Cat Group meeting at Michael's. We were using Danny's 532 100Mw DPSS laser. The film I brough was not even close to being saturated, was 24 hours old, traveled by air from Baltimore to Texas (warm, cold, warmer). I believe it was about 2.5 - 3% AmDi. The set up was, the laser was on a dressing with a mirror stearing the beam down to the floor. The Plate was lying right on the object. I think the exposure was about 10 or 15 minutes. If I recall correctly, we got some pretty good holograms. This was an improvised set up to say the least. My biggest point here is, if you are doing 15 minute exposure and need to to to 20 (33% more), why not do that to allow the addional light to get to the diffusing object instead of loading up the plate. That's just my opinion and my recollection, but whatever works works.

Dave, with that much AmDi in the plate, are you using spill over lighting to get more lighting to the object. Or do you really not see fall off of brightess of the object with a standard SBR?

Thanks Danny, but it's is not hardware. And it's a little too personal to put on the forum. But again, thank you for offering.

Yes you must be right there John. If one can tolerate longer exposures then it must lead to more light from object. The miracle is to be able to record anything at all at 532nm. because of that graph. I still cant get over how well it works at 532nm.
I did not push the button originally on the spectrometer to print out a transmission graph I’m afraid.
The reason chemists record absorption spectra rather than transmission ones is that
the absorption one is based on “natural logarithms “ and the peak height is somewhat linearly related to the concentration of dye molecules due to the "Beer-Lambert law" and all that. But the transmission graph as a percentage transmission is the best for judging how much light we are losing . It has a very similar upside down shape to the absorption one .
Jeff

[JohnFP]

Thanks Jeff, I wasn't sure if the tranmission was close to the absorbtion due to a litle reflection. But I guess it's close enough. Good to hear from you.

[Danny Bee]

hey i was thinking on trying Chlorophyll with dcg to extend to red, dont know if it will work but got a good collection of it now very dark green

[jeff-blyth]

hey i was thinking on trying Chlorophyll with dcg to extend to red, dont know if it will work but got a good collection of it now very dark green

Sounds like a great idea Danny. BUT have you checked the price of it from Sigma after they have boiled up their spinach? It is:-

Over $30,000. per gram!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Now I just know you could supply folks here after boiling up your own spinach for just $2
per gram or maybe $ 20 with a bit of profit motivation thrown in! And Dave could even modify his coating technique to cope with
spinach modified DCG for red lasers.
and now,
Back on the serious discussion on dichromate concentration dilemma.
As the exposure progressess the light to the object increases too as the yellow Cr IV gets converted to the lowly absorbing green CrIII. I think that this going to be a much bigger effect with low initial dichromate concentrations and exposure to high- efficiency blue light than with high concentrations and very low efficiency 532nm green light. I suppose what this all boils down to is the question for everyone here:-
Where is the concentration level point of diminishing returns in diffraction efficiency for a given laser’s wavelength and power?
Jeff