Qite broadband contact copies from yesterday, but I cannot get out the milkyness and there is allways something like mirror efect - in some angle of wiew the plate appears like holographic mirror which complete suppress the image.
DCG 4/12/100; 0,1mm distance tape, 20 min exposure under 50 mW spread to 35 cm elipse. Processed in pyrosulphate/alum/water 20g/4g/400ml, washed, IPA 80%, 100%.
Holos from yesterday
-
info.crew
Holos from yesterday
- Attachments
-
- DSC01386.JPG (143.7 KiB) Viewed 4825 times
-
- DSC01387.JPG (137.7 KiB) Viewed 4832 times
-
- DSC01388.JPG (139.86 KiB) Viewed 4833 times
-
info.crew
Holos from yesterday
And the last two.
- Attachments
-
- DSC01389.JPG (131.84 KiB) Viewed 4807 times
-
- DSC01390.JPG (137.61 KiB) Viewed 4816 times
-
JohnFP
Holos from yesterday
Hey info.crew, your holograms are looking good. But I have to say it still looks like the hologram is grossly over exposed.
Contact copies are a little tricky. You have to make sure you are exactly, or as close as you can, to Brewsters angle to minimize the reflection off the H1 or you will get exactly that "mirror" effect you are speaking of.
Also,
When I do contact copies I make the H1 such that the film is facing the object. Then in the copy set up the H1 plate is flipped and the H2 is placed such that the film of the H2 faces the film of the H1. This helps minimize that reflection I spoke of.
Contact copies are a little tricky. You have to make sure you are exactly, or as close as you can, to Brewsters angle to minimize the reflection off the H1 or you will get exactly that "mirror" effect you are speaking of.
Also,
When I do contact copies I make the H1 such that the film is facing the object. Then in the copy set up the H1 plate is flipped and the H2 is placed such that the film of the H2 faces the film of the H1. This helps minimize that reflection I spoke of.
-
info.crew
Holos from yesterday
I didnt thing about some overexpose, bercause if I make less exposion, the milkyness is much higher. I do not know, how to avoid that. Brewster angle for the float glass is the 56,3°?
I used about 50° and now I am thinking about to buy antireflex float glass for making plates.
I used about 50° and now I am thinking about to buy antireflex float glass for making plates.
-
JohnFP
Holos from yesterday
Milkiness is caused by the film being too soft. There are many ways of fixing this problem (making the emulsion harder) but increasing exposure is not the best way. It sounds as if the gelatin you are using is naturally soft. So let's look at some other ways to use your gelatin and get it harder.
Seventh Son has already introduced a hydrating technique but I believe your gelatin does not get hard enough to start with, so lets hold off on that for a while. You can implement that after one of the below methods allows a non milky hologram with lower exposure.
You could try any of these or combination of these with a shorter exposure time.
1. First, shorten your exposure let's say by half (10min). Then after the exposure hold the hologram in your hand by the edges and with the laser shutter open, hold the hologram in the laser light and keep moving it side to side. The idea is to get additional crosslinking and thus hardening without actually creating any more fringes. Do this for the remainder of time of your original exposure so do this for the 10 minutes you took off the original time. If you cut your exposure to 5 minutes then do this for 15 minutes. After some testing you may be able to cut this additional lighting time down.
2. After a shorter exposure, 5 or 10 minutes, and before processing put the hologram in a lab oven (do not contaminate your cooking oven) and bake it at about 120F (49C) for 3 to 5 minutes. It's best to have a piece of flat steel in the oven to lay the hologram on, so when you put the hologram in the oven, it heats up all at once. Then when you take the hologram out of the oven, place it on anther piece of flat steel to cool it evenly.
3. Prior to exposure do the above baking technique. Then let the hologram cool and stablize to ambient room temperature and humidy before shooting.
4. Decrease the amount of water in your homemade "Fixer" and increase your fixing time. You'll have to test the increased fixing time as you never stated how long you fix. With higher concentrated formula, you may not have to increase fixing time at all but a little testing will tell. If you get too long, greater then 2-3 minutes, then decrease water. I'ts best to keep fixing to about 1 - 2 minutes. Try 20g/4g/300ml. How long does it take the orange to turn completely blue and wash out of the hologram while in the fixer?
5. Put a couple of drops of Glycerol (glycerine) in your original emulsion formula. This will help speed up dark reaction in those 24 hours which will essentially cause the film to be a little harder.
6. Age you plate in a very dry area for 2 maybe 3 days instead of 1 day. You could make a few plates and shorter expose a plate each day and see what happens as the plate ages.
------------------------------------------------------------
Oh and finally, try to get the beam at 56 - 57 degrees for brewsters.
Seventh Son has already introduced a hydrating technique but I believe your gelatin does not get hard enough to start with, so lets hold off on that for a while. You can implement that after one of the below methods allows a non milky hologram with lower exposure.
You could try any of these or combination of these with a shorter exposure time.
1. First, shorten your exposure let's say by half (10min). Then after the exposure hold the hologram in your hand by the edges and with the laser shutter open, hold the hologram in the laser light and keep moving it side to side. The idea is to get additional crosslinking and thus hardening without actually creating any more fringes. Do this for the remainder of time of your original exposure so do this for the 10 minutes you took off the original time. If you cut your exposure to 5 minutes then do this for 15 minutes. After some testing you may be able to cut this additional lighting time down.
2. After a shorter exposure, 5 or 10 minutes, and before processing put the hologram in a lab oven (do not contaminate your cooking oven) and bake it at about 120F (49C) for 3 to 5 minutes. It's best to have a piece of flat steel in the oven to lay the hologram on, so when you put the hologram in the oven, it heats up all at once. Then when you take the hologram out of the oven, place it on anther piece of flat steel to cool it evenly.
3. Prior to exposure do the above baking technique. Then let the hologram cool and stablize to ambient room temperature and humidy before shooting.
4. Decrease the amount of water in your homemade "Fixer" and increase your fixing time. You'll have to test the increased fixing time as you never stated how long you fix. With higher concentrated formula, you may not have to increase fixing time at all but a little testing will tell. If you get too long, greater then 2-3 minutes, then decrease water. I'ts best to keep fixing to about 1 - 2 minutes. Try 20g/4g/300ml. How long does it take the orange to turn completely blue and wash out of the hologram while in the fixer?
5. Put a couple of drops of Glycerol (glycerine) in your original emulsion formula. This will help speed up dark reaction in those 24 hours which will essentially cause the film to be a little harder.
6. Age you plate in a very dry area for 2 maybe 3 days instead of 1 day. You could make a few plates and shorter expose a plate each day and see what happens as the plate ages.
------------------------------------------------------------
Oh and finally, try to get the beam at 56 - 57 degrees for brewsters.
-
Colin Kaminski
Holos from yesterday
Nice post John! Can you add it to the DCG troubleshooting section of the wiki? 
-
JohnFP
Holos from yesterday
Colin, I could not find a section so I added one.
Info.crew, I am still very curious how your hologram acts in the homemade "Fixer".
1. How long does it take for the blue to be washed out of the hologram? I process in a white tray so I can see all the blue come out. The I continue for about another 15 seconds.
2. How long do you fix for, the total time in fixer?
3. What is the temperature of your fixer?
4. How do you aggitate?
Also, what is the temperatures of your water wash and alcohol baths?
Finally, how do you final dry after the last alcohol bath?
Info.crew, I am still very curious how your hologram acts in the homemade "Fixer".
1. How long does it take for the blue to be washed out of the hologram? I process in a white tray so I can see all the blue come out. The I continue for about another 15 seconds.
2. How long do you fix for, the total time in fixer?
3. What is the temperature of your fixer?
4. How do you aggitate?
Also, what is the temperatures of your water wash and alcohol baths?
Finally, how do you final dry after the last alcohol bath?
-
info.crew
Holos from yesterday
I found, that the gelatine surface in the fixer turns wrinkly, and that greatly afect visibility of the image. I do not know why this happen.Info.crew, I am still very curious how your hologram acts in the homemade "Fixer".
1. How long does it take for the blue to be washed out of the hologram? I process in a white tray so I can see all the blue come out. The I continue for about another 15 seconds.
2. How long do you fix for, the total time in fixer?
3. What is the temperature of your fixer?
4. How do you aggitate?
Also, what is the temperatures of your water wash and alcohol baths?
Finally, how do you final dry after the last alcohol bath?
I made the fixer according to the your formula:http://holographyforum.org/phpBB2/viewt ... 254#p48946
The time in the hardener wit reducing agent is 1,5 minute to 2,5 minute. In 1 minute the blue Cr(3+) come out. The bath has about 25 up to 28°C - room temp. Then I wash it in running tap water. I agitate it by periodic tilting the can in hands. All the other baths has the room temp.
-
JohnFP
Holos from yesterday
Info, you are using pyrosulphate inestead of Sodium Metabisulfite. We may need Jeff to comment on the differences of those two chemicals.I found, that the gelatine surface in the fixer turns wrinkly, and that greatly afect visibility of the image. I do not know why this happen.
I made the fixer according to the your formula:http://holographyforum.org/phpBB2/viewt ... 254#p48946
The time in the hardener wit reducing agent is 1,5 minute to 2,5 minute. In 1 minute the blue Cr(3+) come out. The bath has about 25 up to 28°C - room temp. Then I wash it in running tap water. I agitate it by periodic tilting the can in hands. All the other baths has the room temp.
If I understand wrinkly correctly then it seems the alum is differentially hardening the "SOFT" gelatin exposed and unexposed fringes a little too quickly. Since the CR is coming out at about one minute, then 1 1/4 minutes should be addequate for the reducer. But it seems you need a less concentrated hardener but more hardening time.
My suggestion would be to make two baths for fixing. One for reducing and one for hardening. I would leave the concentration of reducer the same and only develop in that bath for 1 1/4 minutes, till blue is gone then 15 seconds. Then reduce the concentation of the Alum solution by half but leave in the hardening bath for double the time, maybe triple. This should do away with wrinking and with some trial and error you shoudl be able to find the optimal time in the hardening bath to be able to reduce your exposure time yet maintain clarity. I have not actually tried the reducer and hardening baths separately so I am not really sure if you should do reducer first or hardening first. My best guess would be the reducer first which will not allow unexposed CR VI to contaminate the hardening bath.
Separating the two will give you more control and allow you to lower exposures to the correct times. If you lower exposure time try the same concentration of Alum but leave it in longer, 2-4 minutes.