Does a reflection hologram have a real image?

Viking · Post by **Viking** » Tue Oct 13, 2009 6:40 pm

Hi there everyone

I would like to know if reflection holograms will show a real image in front of the plate when lit and viewed from the opposite site, or does this only work with transmission holos? I have finally made a reflection hologram bright enough (YES FINALLY! :dance: ). When I flip the plate, the hologram is still behind the plate and very distorded somehow. I guess that the distortion is from not using a collimated beam and image being pseudoscopic, but is'nt it supposed to be in front of the plate? Just wondering wether my hologram or my brain got stuck!

holo_cyware · Post by **holo_cyware** » Tue Oct 13, 2009 7:30 pm

Your hologram is OK; this is what it should look like. You need a second step (H2 transfer) to really get it ouside the plate.

Now imagine what happens when you make a denisyuk with the emulsion on the laser side, and you want to paint it in black: game over.

JohnFP · Post by **JohnFP** » Wed Oct 14, 2009 10:22 am

Absolutely. That's how you use a SBR (Single Beam Reflection) as a master to make a copy.

It sounds as if you flipped it incorrectly. If you have overhead lighting in your SBR set up, then you need to flip the plate top to bottom. If you have a side reference beam in your set up, then flip the plate side to side. It will be completely in front of the plate but it will be pseudoscopic, that is inside out and backwards and it will move with the movement of your head. So you will see more of then right side of the hologram when moving your head to the left and visa versa. Also, if you are still having problems, then try to varry the distance your eyes are from the hologram, closer - further away.

Viking · Post by **Viking** » Wed Oct 14, 2009 8:59 pm

Thanks for your replys.
I didn't know you could make H1-H2s from a reflection holo, I thought it had to be a transmission. So I will just have to look again for that real image. Well first I must make a new relection, this one I just painted black. I allways looked at it with a black background, thought it would be the same. Big difference! It went from just ok to much brighter. I never expected such a big difference. Still have much to learn... I know that H1-H2 is the way to go, I want to give split beam a try to get a good transmission and then make a copy. I really want to make a hologram 'sticking out' from the plate, these are for me the most impressing. Just need to get the beamsplitter and spatial filter to work. Hmm and a collimation mirror would be nice... Hey what happened here? Made one lousy holo and got hooked! Find myself thinking about holography all day, should I be worried?

JohnFP · Post by **JohnFP** » Thu Oct 15, 2009 12:57 pm

Nope, you don't have to be worried, you sound like the rest of us...

Welcome to the family. It's better then being hooked on a MMOG (Massively Multiplayer Online Game).

The object sticking in front of the plate can be done via reflection to reflection also but since you would not have any control over beam ratios it will not be as bright as a transmission to reflection in silver halide.

Viking · Post by **Viking** » Thu Oct 15, 2009 7:40 pm

Hi there John. Thanks for your reassurance and welcome. And for the greatest clue ever! Sometimes things are right in front of your nose and you
don't see it! "That's how you use a SBR (Single Beam Reflection) as a master to make a copy.". This morning when driving to work I suddenly realised
what you ment. Almost drove off the road from excitement! You mean that I can make a reflection Dennisyuk, then put it close to a plate and one beam
will be reference bean for the H2 and lighting the H1 at the same time. Am I right? I guess for this to work the H1 must be made with a (near) collimated
beam. I'm thinking about putting my laser diode off the optic table as far away as possible and adjusting its lens to get a beam just big enough for the
job. But then it hit me, reflection holos don't playback in laser light unless it is the same wavelength right? I mean if my bleach is not a nonthrinking one
it should not work as fringes changes so does replay wavelength (does anyone know if PBU-Amidol bleach is a nonthrinking one? (Potassium Persulphate, Citric Acid, Cupric Bromide, Potassium Bromide, Amidol)). Then perhaps it would be possible to postswell with sugar substitute to get it right again. If I do this and I don't get it right, can I just wash out the sugar and post swell again with a different concentration?
Or can I use an unbleached reflection holo for this? In this case I have some Ilford ilfostop for bw photografs. Can this be used after the developer
instead of bleaching? I'll be using SM-6 developer (Sodium Hydroxide, Phenidone, Ascorbic Acid, Sodium Phosphate (dibasic)). Ran out of JD2
chems, hate to change chems at this early point in my endevour, but buing from outside of Europe is too expensive (did that once, the price got
doubled at customs - yes doubled!). Well I hope someone can help me clear up these points. Can't wait to give it a try...

JohnFP · Post by **JohnFP** » Thu Oct 22, 2009 12:04 pm

Hey Viking, Sorry it took so long to get back to you.

Hi there John. Thanks for your reassurance and welcome. And for the greatest clue ever! Sometimes things are right in front of your nose and you
don't see it! "That's how you use a SBR (Single Beam Reflection) as a master to make a copy.". This morning when driving to work I suddenly realised
what you ment. Almost drove off the road from excitement! You mean that I can make a reflection Dennisyuk, then put it close to a plate and one beam
will be reference bean for the H2 and lighting the H1 at the same time. Am I right? YES I guess for this to work the H1 must be made with a (near) collimated
beam. YES I'm thinking about putting my laser diode off the optic table as far away as possible and adjusting its lens to get a beam just big enough for the
job. That would be the best without a collimator But then it hit me, reflection holos don't playback in laser light unless it is the same wavelength right? Correct I mean if my bleach is not a nonthrinking one
it should not work as fringes changes so does replay wavelength (does anyone know if PBU-Amidol bleach is a nonthrinking one? (Potassium Persulphate, Citric Acid, Cupric Bromide, Potassium Bromide, Amidol)). Then perhaps it would be possible to postswell with sugar substitute to get it right again. If I do this and I don't get it right, can I just wash out the sugar and post swell again with a different concentration? Yes you can, I have done this
Or can I use an unbleached reflection holo for this? Unbleached would work, in fact I never tried it but unbleached may be better as it has a nice black background, although unbleached holos are usually not as bright as their bleached brothers. In this case I have some Ilford ilfostop for bw photografs. Can this be used after the developer
instead of bleaching? If it is a high contrast developer it should be ok, but I am not familliar with that specific developer. I'll be using SM-6 developer (Sodium Hydroxide, Phenidone, Ascorbic Acid, Sodium Phosphate (dibasic)). Ran out of JD2
chems, hate to change chems at this early point in my endevour, but buing from outside of Europe is too expensive (did that once, the price got
doubled at customs - yes doubled!). I have used Kodak D-19 with sucess. Well I hope someone can help me clear up these points. Can't wait to give it a try...

Viking · Post by **Viking** » Thu Oct 22, 2009 1:42 pm

Hey there John. So good to hear from you again.

Thank you so much for clearing up these details for me. Hope to get time this weekend to go for it. I'm ready.
Well one dilemma remains. Perhaps the biggest of them all: If you don't have a job you have no money for plates and stuff.
If you do have a job, you have no time for making holograms (on a greek salary, still no money either!). Anyone found a solution to that one??? :wall:

JohnFP · Post by **JohnFP** » Thu Oct 22, 2009 4:52 pm

Sure, give up sleep and lots of coffee. But only do that once or twice a week. :whistle:

Viking · Post by **Viking** » Thu Oct 22, 2009 5:29 pm

So I do qualify as a holographer after all. By now I do coffee intravenously!