Grainy holograms

[holomaker]

you know by changing processing temps will also effect the grainyness, years back when i was starved for mw i would heat the developer and would speed the film up quite a bit (and the grainyness to), so developing in cooler bath may help as well. And dont waste a whole plate please, cut it in four pieces first and save three pieces for more future testing!

[Johnfp]

One more thing since this is definitley a transmission hologram. Take the hologram and hold it in the light at close to angle of recording. Now try to get you face as close to the plate as possible to look into the hologram. Be careful not to let the laser light go into your eyes but you shoudl be able to get close enough to see not only the object but possibly the edges of the platehoder, other optics or anythign else close to the object in the recording set up. The reason I ask is it may be possible that something in your set up is reflecting additional light to the plate in this grainy fashion but you cannot see it as it comes into play when you illuminate the object.

I know with my argon laser that I can see minute reflections off object clear accross the table if I look hard enough. Even such things as the light reflecting off a black card-off or black curtain. And surely it is easy to see if you missed something and you get a hologram of one of your mounts in close proximity to the object.

Another question. When you are developing, does little spots of these grains develop first? They may not be visible as I am not sure what kind of safe light you are using but thought I would ask.

[rzeheb]

O.K., so I bit the bullet and developed an unexposed plate (sorry Dave, I didn't attempt to cut it). Survey says....... not fogged. I also shot another holo last night using a dull metalic object (bronze cannon). I scrupulously checked for every possible source of stray light that might have been hitting the plate and couldn't find any. Unfortunately, because of my table geometry I couldn't get really close to the developed plate as you suggested John, so it's possible I might still be missing something. Nevertheless, the holo turned out the same as all the others; looks good off-axis but still exhibits what I am calling this grainy, snowy interference at the plane of the plate when viewed at the same orientation with respect to the reference beam as when it was shot. I have yet to order fresh D19 so I guess that'll be next.

[holomaker]

Ron you checked the polarisation ?i would back your object away from the film plate an inch or two and see what happens. i still suspect the brightness off the object is causing this, how close is your object to the film plane?