Spectrosensitometer

[Hologram]

Blu-Rays use LASER diodes at 405 nm - funny thing is that is considered a "violet" wavelength!

It is. Moreover, in contrast to what the eye sensitivity curve suggests, these lasers are highly (painfully) visible!

I see Sony unvieled a Blu-Ray prototype in Oct. 2000 - I'm not sure when the diodes were invented, but it's certainly a few years before they showed the Blu-Ray.

Meanwhile these lasers have become pretty cheap and are available with powers >1W. I assume they might be interesting for photographic applications involving the use of dichromates or ferric salts etc.

 

[holmburgers]

Thanks for the answers to my questions Kirk.

So if we imagine a simple "shoe-box" spectrosensitometer, it might look like this.

Light source (let's imagine a simple tungsten flash-light bulb for now) -> far enough away or with collimating lens -> diffraction grating -> focusing lens -> film plane.

The light needs to hit the grating dead on, and then we need to focus that image sharply onto the focal plane. Any idea what kind of lenses we'd need, and approximate focal lengths? There are some acrylic lens sets that you can get, or we might be able to order some more appropriate lenses, both from Edmund.

It seems one of the lens kits would be great for this; they have all the different types of lenses for abotu $15.

 

[iandvaag]

About a month ago I passed up an opportunity to buy a nice monochromator and high pressure Hg lamp for a decent price. I didn't buy it because, as a grad student I have very little time for home emulsion making. Due to recent circumstances, I've got a bit more time and I really wish I had bought them.

Have there been any "lurkers" on the forums in the past number of years who have secretly built spectrosensitometers and told nobody about it?

Interestingly, some group in China published a paper on building a spectrosensitometer in 2019, so I guess I'm not the only crazy one: http://www.oejournal.org/J/OEE/Article/Details/A190220000012