Heliochrome - huh??

[htmlguru4242]

While doing some internet research on Autochromes, in order to help me with my current [and very slowly progressing expreiments], I stumbled upon something about a process called "heliochrome". It apparently involves the formation of a color image on a silver chloride plate. This sounds interesting, but does not make much sense, chemically or logically.

Does anyone have any information on this?

 

[JG Motamedi]

The Heliotype (AKA Hillotype) was supposedly a way of making color daguerreotypes. It was pretty complicated, even by daguerriean standards, and I don't know if it actually worked or was just a scam. I have never seen or heard of a real Heliotype.

Some details here: http://americanart.si.edu/collectio...xhibits/helios/secrets/text_thehillotype.html

 

[Photo Engineer]

There is a method of obtaining color photographs by exposing a plate through the base with the emulsion in contact with a pool of mercury. The interference patterns that form are based on the wavelength of the exposing light, and when developed and then viewed in contact with a pool of mercury will reproduce the original colors in the scene with great fidelity with no dyes or other chemical manipulation.

IIRC, I saw one, once, a number of years ago at George Eastman House. IDK if it is still there or if it was a special event. It was quite striking.

I don't remember the name of the process or the inventor, but it strikes me as being one of the 'famous' people in science from the 19th century. It never became popular due to the difficulty of hauling around a pool of clean mercury.

PE

 

[sanking]

The Heliotype (AKA Hillotype) was supposedly a way of making color daguerreotypes. It was pretty complicated, even by daguerriean standards, and I don't know if it actually worked or was just a scam. I have never seen or heard of a real Heliotype.

Some details here: http://americanart.si.edu/collectio...xhibits/helios/secrets/text_thehillotype.html

There was a long and well-researched article on the Hillotype in an issue of Camera Arts from the early 80s. The conclusion of the author, as best I can recall, is that the process was not capble of doing what its creator claimed since the results could not be replicated.

Sandy

 

[Donald Qualls]

I've seen photos of "color Daguerreotype" images (they weren't called Heliochrome, at least in that article) in a 1990s vintage Scientific American I have around here somewhere -- it was a history of early color photographic processes. The process, as set forth there, was to put a silver chloride emulsion directly onto glass and expose through the glass with the emulsion in contact with liquid mercury. There was little more said about it, but the images presented were very colorful.

It looked to me as if it would be simpler to put the silver chloride onto a silver plated layer on the glass, expose from the emulsion side, and thus keep the reflective surface with the image. However, where the description stumbled, for me, was in lacking an explanation of how interference layers (essentially in-situ dichroic filters) could form without some kind of support, or how silver (even developed as a Dag) could become reflective enough to produce a dichroic effect when forming at a molecular scale from reduced halide. Given that hand coloring Dags was quite common (though the colors used were traditionally quite pale) but Dags were never transparent, I'm led to wonder if the Heliochrome plates weren't in fact early transparent negatives (i.e. collodion wet plate), colored on the collodion surface; viewing by relfection would intensify the colors and make the areas that would be light in a tintype or ambrotype dark.

I suppose its even possible that a collodion emulsion exposed the way the Heliochrome was said to be made could support interference colors when viewed by reflection; there would need to be enough emulsion thickness to support multiple-layer interference, but I think the sensitization of collodion penetrates more than deeply enough for this, and the grain in collodion negatives is plenty fine...

 

[JG Motamedi]

I remembered a bit more about the Heliotype. Apparently, Levi Hill, a well known Broadway Daguerreotypist (back when B'way meant dags, and not cheesy musicals), announced through Humphrey's Journal (Daguerreotypy Journal) that he had come up with a way of making color daguerreotypes. Apparently he started to sell the "secret" to various practitioners for large sums of money, however the process never worked and eventually Levi Hill was denounced as a huckster.

More details here, notably S. D. Humphrey's defense of Hill: http://americanart.si.edu/collectio...xhibits/helios/secrets/text_thehillotype.html

I have heard of the Hg on glass process, but the Heliotype supposedly employed a silver-coated daguerreotype plate.

 

[removed account4]

didn't joseph nicephore niepce also come up with some sort of color photographic image way back in the early days, but it wasn't fixed, because he spent his whole life trying to recreate his photographic experiment and failed ... no one believed him ?
i remember reading about it but i can't remember if i actually read it, and no one believed me ... i guess you could say i suffer from niepceism

 

[Loose Gravel]

Sounds like the Lippman process:

In 1891 Lippmann revealed a revolutionary colour-photography process, later called the Lippmann process, that utilized the natural colours of light wavelengths instead of using dyes and pigments. He placed a reflecting coat of mercury behind the emulsion of a panchromatic plate. The mercury reflected light rays back through the emulsion to interfere with the incident rays, forming a latent image that varied in depth according to each ray's colour. The development process then reproduced this image, and the result, when viewed, was brilliantly accurate. This direct method of colour photography was slow and tedious because of necessarily long exposure times, and no copies of the original could be made. It never achieved popularity, therefore, but it was an important step in the development of colour photography.

For which he won the Nobel prize in Physics in 1908

 

[3Dfan]

According to this article - http://www.newscientist.com/article/mg17623685.300-the-prince-of-humbugs.html - Hill's results have been replicated, thus vindicating his suppressed invention. It was not the Lippmann process, and it predates Maxwell's color photographs, being from the 1850s.

 

[JBrunner]

didn't joseph nicephore niepce also come up with some sort of color photographic image way back in the early days, but it wasn't fixed, because he spent his whole life trying to recreate his photographic experiment and failed ... no one believed him ?
i remember reading about it but i can't remember if i actually read it, and no one believed me ... i guess you could say i suffer from niepceism

Niepce called his first process "heliograph" (sun writing) but it has little in common with the process being discussed here. If Niepce experimented with color, I am unaware of it. Not saying he didn't, just that if so, I am not aware that he did.

 

[htmlguru4242]

I recall hearing about some Neipce color experiments. I think that they're mentioned briefly in the Silver Sunbeam and other such texts. I'll find it later this evening.

And, good article 3Dfan