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Thermal Paper Polaroid

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Re: Thermal Paper Polaroid

#41

Post by skykooler »

tigershark wrote: post #37
goldenkey wrote: post #35

Earlier quoted context omitted.

Holography does this though with much stronger lights than regularly experienced. https://en.wikipedia.org/wiki/Holography Why not just take this idea to its analog completion - does an analog light amplifier exist? Some google searching says the answer is nay. I guess analog amplification of electricity is a lot simpler than light because of quantum effects. https://www.sciencedaily.com/releases/2017/01/170105123047…

Of course it does exist. It’s a “light amplification by stimulated emission of radiation” device better known as laser. Although it can’t be used to amplify the light field in its entirety.

What if you had an array of pixel-sized lasers?

Re: Thermal Paper Polaroid

#42

Post by tigershark »

skykooler wrote: post #41
tigershark wrote: post #37

Earlier quoted context omitted.

Of course it does exist. It’s a “light amplification by stimulated emission of radiation” device better known as laser. Although it can’t be used to amplify the light field in its entirety.

What if you had an array of pixel-sized lasers?

A laser can amplify only a very specific frequency and it will lose all the color information. At that point it won’t be analog light amplification given that the output light won’t have any of the characteristics of the input.

Re: Thermal Paper Polaroid

#43

Post by goldenkey »

tigershark wrote: post #37
goldenkey wrote: post #35

Earlier quoted context omitted.

Holography does this though with much stronger lights than regularly experienced. https://en.wikipedia.org/wiki/Holography Why not just take this idea to its analog completion - does an analog light amplifier exist? Some google searching says the answer is nay. I guess analog amplification of electricity is a lot simpler than light because of quantum effects. https://www.sciencedaily.com/releases/2017/01/170105123047…

Of course it does exist. It’s a “light amplification by stimulated emission of radiation” device better known as laser. Although it can’t be used to amplify the light field in its entirety.

I know about lasers. I meant the entire waveform. Vacuum tubes do that for electricity. It seems the only similar method is to use a lens, a smaller sensor, and hopefully the initial light is bright enough so when it's miniaturized, it does the chemical/electrical work necessary on the film or sensor. Film negatives already uses this concept - taking ordinary light and increasing its power by minifying it over a smaller surface area.

Re: Thermal Paper Polaroid

#45

Post by michrassena »

anfractuosity wrote: post #31

I'm wondering could you sort of use thermal paper directly with a lens and a long enough exposure to directly create an image on thermal paper?

Does thermal paper darken if left in the sun? If not, I don't see how a projected image will be hot enough to burn an image. Even if it warms up the paper, the process has to happen fast enough that the heat isn't conducted to the surrounded area first. Maybe you could make a solargraph with thermal paper, where the sun burns a path over many days.

Typical photographic paper (developed in the darkroom) or direct positive paper is better suited to what you're suggesting.

Re: Thermal Paper Polaroid

#46

Post by [deleted] »

michrassena wrote: post #45
anfractuosity wrote: post #31

I'm wondering could you sort of use thermal paper directly with a lens and a long enough exposure to directly create an image on thermal paper?

Does thermal paper darken if left in the sun? If not, I don't see how a projected image will be hot enough to burn an image. Even if it warms up the paper, the process has to happen fast enough that the heat isn't conducted to the surrounded area first. Maybe you could make a solargraph with thermal paper, where the sun burns a path over many days. Typical photographic paper (developed in the darkroom) or direct posi…

[deleted]

Re: Thermal Paper Polaroid

#47

Post by dmix »

kxtells wrote: post #27
dmix wrote: post #14

He says in the video you can’t buy one but I recently bought a Polaroid camera as a gift at Urban Outfitters for $100, plus the expensive film ($30 for 8 shots) that goes with it. Is this different in some way?

The Polaroid Originals film is expensive, but not 30$ for 8 shots. More like ~20$ https://us.polaroidoriginals.com/products/color-instant-film...

I should have noted I bought it with CAD not USD. So about the same with tax...

Re: Thermal Paper Polaroid

#48

Post by js2 »

> Long before the final assembly I'd wired the little LED under the viewfinder to one of the pi's GPIO. I'm not sure what it originally represented...

From the manual[1, 2]:

When you are not using flash, a red light may appear under the viewfinder as you begin to press the shutter button. It warns that the lighting on the scene is not bright enough for picture taking without a tripod or other firm support.

Also, this bit from the manual is somewhat amusing given the extraordinary chain of events occurring inside the hacked camera:

As you begin to press the shutter button, your camera releases sound waves to the central part of the scene. The frequencies are far beyond our range of hearing and travel at the speed of sound. The split second it takes for the sound to reach your subject and the echo to return is fed into a tiny electronic computer inside the camera. The computer uses this time measurement to calculate the distance between the camera lens and your subject, then signals a motor to turn the lens until your subject is in sharp focus. This extraordinary chain of events takes place in less than 1/3 of a second.

[1] http://www.cameramanuals.org/polaroid_pdf/polaroid_sonar.pdf

[2] Found via http://butkus.org/chinon/ which itself is a lovely 1990's style web-site. I couldn't help but donate $3.

Re: Thermal Paper Polaroid

#50

Post by derefr »

Cynddl wrote: post #25
joezydeco wrote: post #13

Just a friendly reminder that most common types of thermal paper contain BPA or BPS. You really should be avoiding these endocrine disruptors when possible. https://www.pca.state.mn.us/green-chemistry/bpa-thermal-pape...

“Most common types of thermal paper contain BPA or BPS” That's not valid everywhere. The European Union decided in 2016 to forbid the use of BPA in thermal paper. [1] BPA is currently still used but will be completely banned in 2020. And, even if BPS will be allowed, EU surveys seem to show that alternatives to BPA/BPS are being considered for thermal paper. [1] https://echa.europa.eu/hot-topics/bisphenol-a

I mean, good for them, but if BPA is "still currently used" and alternatives to BPS are only "being considered", then in the EU both BPA and BPS are still in thermal paper right now, yes?

So, in fact, it is valid to say that "most common types of thermal paper contain BPA and BPS."

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