Holographyforum.org / holowiki.org

Hey !

I just realized an obvious and cruel truth.
I won't be able to record satisfying holograms on this HOLO 250 PAR film with my HeNe laser !

The Holo film is designed to be sensitive in the very narrow area of 694nm (meant to be used with pulsed ruby) where my HeNe is most likely around 632nm :

[attachment=0]wavelenghts.jpg[/attachment]

This also explains why the exposure with a laser LED works better, the led must be some "InGaAlP" diode which emits somewhere between 630-685, probably in my case nearer to 685.

When reading the wonderful document shared by Ed here : http://edweslystudio.com/Materials/AgX/Ilford/WoodSPIE6150186.pdf I can read that by this time Illford preconised to chemically process the "master holograms" which were recorded in 632 so that they would be shifted toward 694 for easier copy. (the holo 250 par film was used in holocopier).

So, as I don't intend to record a master transmission hologram (yet) then shift it 60nm up, i wonder if there would be any way to somehow shift sensitivity of the film closer to 630nm ? some undying maybe ? anyone heard of such thing ? I know we can pre-swell films somehow, would that help ?

Thing is the longer exposure time, the higher the chances of a slight movement of the plate/object, whenever I try to go farther than approx 15 seconds I seem to loose the image completely on a "random" basis, like, sometimes I have a picture at 16 seconds sometimes not.

I have to improve again my stability if I want to go farther than 15 secs of exposure. Of course with your pulsed laser stability is no trouble xD

I'll make an exposure serie with the subject "touching" the film to make sure to focus on image contrast, I think the best I could achieve with this combination of laser/film was 1.5cm deep scene before it disapears in the black fog.

The holos of the waffle iron were pretty much what you would want, see the pictures earlier in the thread. Whether or not the magic came from the pulsed laser, not sure, as I haven't tested the film in single beam reflection mode with a CW laser.

But I did shoot a transmission holo with it, and thought it was pretty good, but I am traveling at the moment so I don't have a chance to take a picture of the comparison of the Holofilm 250 vs. Agfa 8E75HD.

Have you done an exposure series on the film? That will tell you everything. Keep going to higher levels of exposure until the image disappears, which tells you that have reached the saturation point and all the and all the developed silver has been removed in the dichromate reversal bleach. The image color will become greener before it disappears.

Hope this helps!

Very nice compilation, I printed several documents :)

I upgraded my 1mw Uniphase 1508P-0 by a 10mw hene tube with power source.

I gave it a few shots on this Holofilm. Result is still clearly not as nice as what I can get out of Ultimate plates from Mr Gentet, but it helps setting up my lab & I feel no gulty when messing up with this low-cost material.

@Ed were you ever able to achieve any "looking nice" Hologram on this Holofilm ? It's very dim for me, maybe because it really requires a pulsed ruby..

Excellent, Ed! Thank you!

I have posted a bunch of brochures and pamphlets and leaflets pertinent to this discussion at: [url]http://edweslystudio.com/Materials/AgX/AgXindex.html[/url]

Have fun!

Hi Thycore,
From what you say about seeing interference (colours )but no red image, ---this indicates I think that you have smudged your reflection fringes due to a tiny movement perpendicular to the plane of the film. Such movements do not do much damage to spurious transmission gratings whose fringes are also perpendicular to the film .(These are created by a spurious reflection from the film /air interface sending back a spurious beam from the same side as your object). I strongly recommend making your film tests initially on simple bright coins by working horizontally and beaming up from underneath as per my posting of 18th February 2017 in the "beginning holography" thread.

I made a new test again, this time I developed in D-19 for nearly 6 minutes.

This time, the film around the exposed area remains transparent :

[attachment=0]IMG_3208.JPG[/attachment]

But, somehow, I see nothing as a hologram (no shiny red/green whatsoever)... the interference pattern shows nicely and with good contrast but nothing pops out, is this possible to have a good inteference pattern but no hologram ? or do I *have* to bleach it to see the hologram ?.

I made a test "without" bleaching, I can clearly see the fringes of my hologram in the center (my microscope lens does not expand my beam much bigger than 10cm diameter, that's why only the center of this 25cm wide film part is dark).

[attachment=0]IMG_3207.JPG[/attachment]

I developed for approx 4 minutes, then I rinced in distilled water for 4 minutes.

The film somwhat quickly turned from transparent to amber-colored like. Is this a sign of under-development ?

Right ! seems I came to the same result as yours :) this was the picture of your test (back from 16 june post) :

[img]http://holographyforum.org/forum/download/file.php?id=6907[/img]

And this is a close view on my bleached & 1 night dried film :

[attachment=1]IMG_3205.JPG[/attachment]

When i emptied my trail back to the bottle, I can cleary see the "deposit" on the bottom of the bottle (I suspect this power-stuff being the same as the one scattered on the film after bleach bath), I wonder if this is "chelated Ag+ stuff" or if this is some other sort of chemical ?

[attachment=0]IMG_3206.JPG[/attachment]

I ordered some Potassium Dichromate (and a gaz mask to handle it safely.. xD) and i'll give it a try !