If you are flipping the plate you will indeed need a converging beam. However you will also be making a psuedoscopic image (if I have my terms right). The image will shift left as you move right and appear inside-out. I have played with this a little with single beam work. The famous test of this is to make a casting of a face so it is hollow. Then when the image is reconstructed it looks like the actual face (not a mold) and the face follows you as you walk by as right and left are reversed.
I put the reflection H2 emulsion away from the H1 and display it in the same orientation so I use a diverging reference beam.
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Advice needed on H2 quality
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Colin Kaminski
Advice needed on H2 quality
Perhaps we will end up with a clear description of orthoscopic, psuedoscopic, real and imaginary images from one of the teachers here that I can cut and paste into the Wiki. I have to sort it out every time and since it has been 3 years since I have made an H1-H2 transfer I would have to get in the lab and prove it to myself again. I'll never forget the time I was setting up an H1 master in a guest lab and ended up with the reference beam coming from the wrong side when the H1 was flipped to make the real image. Since I was not making the H2s it was Michael that noticed and he either had to be very creative in his copy or he remastered the H1.
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John Sonley
Advice needed on H2 quality
Colin - from what I read, I suspect that I'm 'doing-it-wrong-way-round'.
Let me try to describe with precision my H1 to H2 transfer:
I view the H1 with the collimated reconstruction beam impinging at the correct angle for brightest reconstruction - (30 deg. in my case'. I view it as a normal image and I then flip it around so that I view the pseudoscopic image and fix the temporarily laminated film on glass into the H1 plateholder with the H1 emulsion facing the H2 plateholder.
I position the H2 plateholder with a white card in it to meet two requirements:
1. Centrally position the image projected from the Hi into the centre of where the 5" X 4" H2 film will be placed
2. Move the whole H2 plateholder framework forwards or backwards to set the required image plane and thereby have my chosen real : virtual image setting
I then under safelight, temporarily laminate the plastic side of my 5" X 4" unexposed H2 copy film on to a glass plate and after stabilising, mount it in the correctly positioned H2 plateholder with the emulsion facing directly towards the H2 reference beam and therefore away from the H1.
At the present moment I am converging this H2 reference beam slightly - is this correct?
Please turn to Pages 185 and 186 of Graham Saxby's 3rd Edition of Practical Hotography:
On page 185 he seems to say that you need a converging reference beam, but on the picture - Fig 12.17 on Page 186 it shows a converging H1 reconstruction beam, which seems all wrong to me, as the H1 was made with a collimated reference beam and a converging reconstruction beam would distort the image from which the H2 is made
Colin, I have been as clear as I am able in my description and I hope it is adequate for you to give me a definitive reply
BRgds
John
Let me try to describe with precision my H1 to H2 transfer:
I view the H1 with the collimated reconstruction beam impinging at the correct angle for brightest reconstruction - (30 deg. in my case'. I view it as a normal image and I then flip it around so that I view the pseudoscopic image and fix the temporarily laminated film on glass into the H1 plateholder with the H1 emulsion facing the H2 plateholder.
I position the H2 plateholder with a white card in it to meet two requirements:
1. Centrally position the image projected from the Hi into the centre of where the 5" X 4" H2 film will be placed
2. Move the whole H2 plateholder framework forwards or backwards to set the required image plane and thereby have my chosen real : virtual image setting
I then under safelight, temporarily laminate the plastic side of my 5" X 4" unexposed H2 copy film on to a glass plate and after stabilising, mount it in the correctly positioned H2 plateholder with the emulsion facing directly towards the H2 reference beam and therefore away from the H1.
At the present moment I am converging this H2 reference beam slightly - is this correct?
Please turn to Pages 185 and 186 of Graham Saxby's 3rd Edition of Practical Hotography:
On page 185 he seems to say that you need a converging reference beam, but on the picture - Fig 12.17 on Page 186 it shows a converging H1 reconstruction beam, which seems all wrong to me, as the H1 was made with a collimated reference beam and a converging reconstruction beam would distort the image from which the H2 is made
Colin, I have been as clear as I am able in my description and I hope it is adequate for you to give me a definitive reply
BRgds
John
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Colin Kaminski
Advice needed on H2 quality
John, I'll read those pages. Perhaps Ed will chime in and clarify things.
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Posted with TouchBB on my iPhone
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Kaveh
Advice needed on H2 quality
Does the image through the lens look blurred in the way it would if you were to look at the H1 in white light?
I think the problem might be that the lens is effectively pushing the position of the image (i.e. the magnified image) a long way away from the image plane. So if you want a sharp image of the magnified image, then you will have to move the H2 for recording. In that case the images to the side will be out of focus.
I think the problem might be that the lens is effectively pushing the position of the image (i.e. the magnified image) a long way away from the image plane. So if you want a sharp image of the magnified image, then you will have to move the H2 for recording. In that case the images to the side will be out of focus.
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rzeheb
Advice needed on H2 quality
Kaveh,
I don't think John is actually using a lense in his holograms; I believe his questions as to converging or diverging reference light on the H2 was more generic. The lense in H2 question was mine from earlier in this thread. When I changed from collimated light to slightly diverging light for the H2 reference beam I got much better clarity and focus on my magnified object while retaining excellent clarity on the remainder fo the image (not seen through the lense). Best, Ron.
I don't think John is actually using a lense in his holograms; I believe his questions as to converging or diverging reference light on the H2 was more generic. The lense in H2 question was mine from earlier in this thread. When I changed from collimated light to slightly diverging light for the H2 reference beam I got much better clarity and focus on my magnified object while retaining excellent clarity on the remainder fo the image (not seen through the lense). Best, Ron.
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Kaveh
Advice needed on H2 quality
Ah, yes. I was replying to your original post that started the thread. Are you saying the divergence change fixed the blurred image through lens? I thought you might have to put the H2 in a different plane to catch it sharp.
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rzeheb
Advice needed on H2 quality
Certainly improved but probably not optimized. Also, the original lens was pretty mediocre displaying a lot of spherical aberation so I decided what I had was good enough and have moved on to greener pastures. :whistle:
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Colin Kaminski
Advice needed on H2 quality
John, we are taking this off topic. But, if we go to far I will split the thread. Graham is talking about an H2 transfer from a transmission H1 that was made from a pulsed laser and was not collimated. Since the H1 reference beam was diverging the H1 replay beam needs to be converging at the precise angle in order to be it's conjugate. He is also showing a collimated H2 reference beam which would not have been my choice unless my replay beam was very far away.
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Posted with TouchBB on my iPhone