On: Sun, May 19, 02 05:04:49 PM
Today I created my first hologram... or lack thereof. I
have made two holograms and both have tured out the same.
In the end each have a yellowish tint and no hologram. I
have tried all the angles possible. I am stumped as what I
am doing wrong. I have everything set up as explained
in "Shoebox Holography". Any help would be greatly
appreciated. Thanks in Advance, Alex|
Colin Kaminski - Sun, May 19, 02 09:51:44 PM It would help greatly if we knew what laser, film and
developing system you are using. Some first things to
check. STABILITY. This is usually the problem. Make sure
there are no air currents in the room. Make sure there is
no noise in the room. Wait till no cars are driving by
outside. Make sure the object sits perfectly flat and does
not wobble. Make sure to warm up the laser.
I put my film on the table and leave the room for 15
minutes to wait for everything to settle. Then I carefully
and gently return and lift out the shutter card. The whole
exposure time I either don't breathe or I take very shallow
If you provide more information we will have more ideas.
Don't get discouraged! We all have had bad exposures. 18.104.22.168
Alex - Mon, May 20, 02 08:50:44 AM Oops, I guess that info would help...
I am using all the items suggested in "Shoebox Holography".
I am using BB-640 plates, the "Infinter200" diode laser
operating at 650nm. I am also using a -12x-12(not sure how
to write it) lens to spread the beam. I am using two
concrete slabs with the shockobsorbing feet and a large
piece of metal on top with magnets to hold the plate. I am
using a little figure placed about 1cm behind the plate. O
and the plates are 2.5" square and I am exposing them for
15 sec(but I tried 10sec also after I developed the first
because I thought it turned dark relatively quickly and
that didn't work etiher). Those are the specifics of the
Colin - Mon, May 20, 02 01:37:27 PM I have used magnets to hold the plate and found unless I
had the poles aligned correctly I could not hold the film
tightly. It should be obvious which way is better when you
flip one magnet and test it. Something to look for is a
faint image of the magnet. It was likely very stable
durring the exposure.
Another thing to try is to touch the object to the plate.
When they are in contact they tend to move together. In a
single beam set up it is only the plate to object
relationship that needs to be stable to 1/8 of 650nm.
On some of my exposures I find the image is there but
really faint and takes me some time to find. The sun works
well to find dim objects. Flip and rotate and change the
angles sometimes a flash of color will go by that turns out
to be a part of your object.
Make sure the object is very white. Single beam holograms
often have very poor object to reference beam ratios and
white objects are better. I often use a white porcelain
figurine for single beam work.
If you place a white card behind the figurine and look at
it's shadow you will see how evenly illuminated it is.
There is no need to spread the beam any wider than the
Check that there is not any wobble between the concrete and
the metal. I use very thin foam between by concrete slap
and metal plate. Your are just looking to even out the
contact not to float the steel so make sure it is very well
It could have been a random movement in the ground when you
made your exposures. Don't be afraid to waste some film
sorting it out. Looking in my log book I did not get a
perfect exposure till my 7th plate. I got an image on my
first but not my second or third tries.
I do not use BB-640 so perhaps one of the group with more
experience as some ideas about finding the proper exposure
time. With my system I can go by image color.
Did you tape the edge of the plate facing the laser? If not
you should have at least rainbow stripes. 22.214.171.124
Alex - Mon, May 20, 02 02:13:00 PM Thank you very much, Colin. I will definetly try that
today. I appreciate all your help.
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