HeCd Omnichrome Laser with Controller

[Jeffrey Weil]

Couldn't you make a master on AgX and contact copy it into resist?

Hello Martin,

That would work but very poorly. It's amazing what happens when you go that deep a blue and into resist. Glass that is perfectly clean for red light becomes totally streaky and messed up beyond imagination. There is no way you could contact something into resist and it not be very dirty and full of stuff that shouldn't be there.

Plus, index matching is pretty much impossible. There's nothing that'll work for both materials, silver and resist.

I'm sure that if you tried hard enough with 17mw you could get something but it would be a very low quality, dim, dirty hologram. Even the smallest speck on an embossing master is reason for it to be rejected. I recently had a job rejected and had to reshoot it. Some of the art was 4/1000th of an inch out of register. Not much but it was right there on the surface. When the holograms are coming off the machine by the thousands if there's a defect that's all your going to see after a while. The same speck in the same spot over and over.

The masters have to be perfect.

Jeff Weil

[Martin]

It's amazing what happens when you go that deep a blue and into resist. Glass that is perfectly clean for red light becomes totally streaky and messed up beyond imagination.

Yes, I've seen this with Bluray DCG etc. exposures.

There is no way you could contact something into resist and it not be very dirty and full of stuff that shouldn't be there.
Plus, index matching is pretty much impossible. There's nothing that'll work for both materials, silver and resist.

That's unfortunate. I guess these photoresists must have a pretty high refractive index.

And, I assume, making a surface relief into gelatin - AgX, DCG etc. - wouldn't provide sufficiently good quality for serious work. On the other hand, the increased speed levels would allow to make large formats...

I'm sure that if you tried hard enough with 17mw you could get something but it would be a very low quality, dim, dirty hologram. Even the smallest speck on an embossing master is reason for it to be rejected. I recently had a job rejected and had to reshoot it. Some of the art was 4/1000th of an inch out of register. Not much but it was right there on the surface. When the holograms are coming off the machine by the thousands if there's a defect that's all your going to see after a while. The same speck in the same spot over and over.

The masters have to be perfect.

I see. Thanks for sharing, Jeff.

[Jeffrey Weil]

And, I assume, making a surface relief into gelatin - AgX, DCG etc. - wouldn't provide sufficiently good quality for serious work. On the other hand, the increased speed levels would allow to make large formats...

A few people have tried this but I don't think its up to the quality of resist. David Pizzanelli did a bunch of work back in the day on using silver relief and casting.

Too dim when it was embossed and noisy too.

Resist doesn't do too many things well but noise is one that it does an amazing job on. Blue light scattering off large chucks of silver halide crystals is pretty noisy but the same light hitting just some small polymer molecules looks great.

Jeff Weil

[Martin]

And, I assume, making a surface relief into gelatin - AgX, DCG etc. - wouldn't provide sufficiently good quality for serious work. On the other hand, the increased speed levels would allow to make large formats...

A few people have tried this but I don't think its up to the quality of resist. David Pizzanelli did a bunch of work back in the day on using silver relief and casting.l

Yes. That's what I learnt also, though I'm not familiar with the details of Pizzanelli's processing schedule. I gathered Jeff Blyth was involved at the early stages of that process.
I believe these attempts were based on the now pretty outdated Agfa materials (8E75, 8E56, Millimask) chiefly. Their grain size was well above 30nm.

Too dim when it was embossed and noisy too.

I guess it occurred due to the large grains.

Resist doesn't do too many things well but noise is one that it does an amazing job on. Blue light scattering off large chucks of silver halide crystals is pretty noisy but the same light hitting just some small polymer molecules looks great.

Regarding AgX I assume this is a question of grain size mainly. The new ultra-high resolution AgX materials (from Slavich, Colourholographics, Ultimate, Sphere-S, Smirnov's materials or even home made AgX emulsions) will scatter a lot less. Coating quality may be another crucial part to consider though.

[Jeffrey Weil]

Hello Martin,

I bet Dinish could answer those questions. He's done work with forcing dcg into a surface relief material. He'll also know the difference in size between a chuck of silver vs a diazo molecule. Scatter is proportional to the size of the particle and the frequency of the light.

Maybe he'll see this thread and jump in.

Jeff