Well done Joe.
It's very difficult to process DCG when you have an uneven exposure like that.
You get the hard parts that want to stay narrow band and the less exposed, soft parts that want to go broadband
I have spent the past two days reprocessing a couple of holograms like that without success, I binned them in the end.
They will now serve as cover plates.
I guess that if you expand your laser beams to give a more even exposure, your exposures will be over an hour long.
Have you measured the energy density of the 532nm reference beam hitting the plate and do you have an exposure in mJ/cm² please?
I'm using exposures of between 25 and 45 minutes for normal DCG, giving me approximate exposures of between 90mJ/cm² and 220mJ/cm² , depending on what I'm shooting (beam ratios). The energy density of the ref beam in the centre of my plate is 48µW/cm².
I haven't done any recent experiments with MBDCG as I'm busy producing xmas cards in DCG.
I believe you are correct ref the dye absorbing a portion of the laser light.
Have you had chance to measure this? I would be very interested in your results.
I did a few measurements some months back using dip and shoot and a gelatin coating of about 8-9µm:
One minute dip in 3% AmDi: Transmission at 532nm = 95.4%
One minute dip in a sensitizing solution using the ratios of chemicals to H2O used in the paper by Jianhua Zhu et al: Transmission at 532nm = 93.2%
One minute dip in my own MBDCG sensitizing solution, (below): Transmission at 532nm = 67.3%
All sensitizing solutions were at ambient (about 18C).
My experimental MBDCG sensitizing solution (approximate):
H2O 600ml
Guanidine carbonate 11.2g
Potassium chromate 940mg
Rhodamine 6G 45mg (22.5ml of a 0.2% stock solution)
Boric Acid used to adjust P.H. to approx 10.1
The P.H. may not be high enough to offset the lower P.H. of the pig gelatin I'm using to coat my plates, but I will continue with my experiments next year.
Steven.
Well done Joe.
It's very difficult to process DCG when you have an uneven exposure like that.
You get the hard parts that want to stay narrow band and the less exposed, soft parts that want to go broadband :-(
I have spent the past two days reprocessing a couple of holograms like that without success, I binned them in the end.
They will now serve as cover plates.
I guess that if you expand your laser beams to give a more even exposure, your exposures will be over an hour long.
Have you measured the energy density of the 532nm reference beam hitting the plate and do you have an exposure in mJ/cm² please?
I'm using exposures of between 25 and 45 minutes for normal DCG, giving me approximate exposures of between 90mJ/cm² and 220mJ/cm² , depending on what I'm shooting (beam ratios). The energy density of the ref beam in the centre of my plate is 48µW/cm².
I haven't done any recent experiments with MBDCG as I'm busy producing xmas cards in DCG.
I believe you are correct ref the dye absorbing a portion of the laser light.
Have you had chance to measure this? I would be very interested in your results.
I did a few measurements some months back using dip and shoot and a gelatin coating of about 8-9µm:
One minute dip in 3% AmDi: Transmission at 532nm = 95.4%
One minute dip in a sensitizing solution using the ratios of chemicals to H2O used in the paper by Jianhua Zhu et al: Transmission at 532nm = 93.2%
One minute dip in my own MBDCG sensitizing solution, (below): Transmission at 532nm = 67.3%
All sensitizing solutions were at ambient (about 18C).
My experimental MBDCG sensitizing solution (approximate):
H2O 600ml
Guanidine carbonate 11.2g
Potassium chromate 940mg
Rhodamine 6G 45mg (22.5ml of a 0.2% stock solution)
Boric Acid used to adjust P.H. to approx 10.1
The P.H. may not be high enough to offset the lower P.H. of the pig gelatin I'm using to coat my plates, but I will continue with my experiments next year.
Steven.