PDA

View Full Version : Carey lea silver



Pages : 1 [2] 3

Ray Rogers
08-29-2008, 12:28 PM
FYI, the same is true of silver halide crystals, and back in the old days they used to judge the extent of ripening by the color of a small sample viewed on a glass slide. The color varied from yellow through green to red, but ended up being obscured when they began using varying amounts of iodide as it gave a strong yellow to red tint to most all crystals.

PE

Yes this is true, and everytime you wash out your equipment (in the light) one can observe colors.

Ron, were they still doing this when you began?

When do you think it totally ended?

I always wondered about this, it is mentioned in both Wall and Baker I think, but (except for one ref I found later) details on how this was done in practice were vague... My hang up is I do not want to lose or fog any of my emulsion, so I could not figure out how one could differientiate between grey, blue, green, yellow and under the ortho-safelight (dark red) I use in my darklab)
Leaving the area did not seem practical to me... do you know how it was done at Kodak?

Did you sacrifice a coating on glass?
and if so, to what light source?

Ray Rogers
08-29-2008, 12:47 PM
Ray, I now see those links do not work... try this one by Carey Lea himself:
http://books.google.com/books?id=K5MOAAAAIAAJ&pg=PA337&dq=carey+lea+allotropic+silver#PPA342,M1

And another contemporary one - that mentions that Rochelle salt and hydroxide is one of many ways which to make Carey Lea's blue allotropic (collodial) silver:
http://books.google.com/books?id=zZMUAAAAYAAJ&pg=PA282&dq=carey+lea+allotropic+silver

It seems to me I was making the blue form when silvering the mirrors as a side product.

Kirk,

Can you explain to me how this site works?
I mean when I go there, I have never been able to get any real value out of it... perhaps there is a difference in the way we are interfacing the material...

Are you able to see whole pages? The entire article?

I am using a Japanese (there doesn't seem to be a choice) google interface that makes it extreamly lame!

Are we seeing the same thing?
I can't imagine you would even post this link if this is all you are seeing.

Ray

Photo Engineer
08-29-2008, 01:00 PM
Ray;

Some workers claimed that they could judge under safelight, and others claimed that they could only see it when a few drops were sacrificed on a glass slide and brought into the light. At the time I joined Kodak, they had ceased using this method about 30+ years earlier when the controlled digests and dual runs went into effect.

Also, for the pages Kirk gives, there is not much to see there, as he talks of the methods in general terms for the most part. I would not try to make a photograde colloid using his instructions, such as they are. They are mainly guidelines.

PE

Ray Rogers
08-29-2008, 02:20 PM
Ray;

Some workers claimed that they could judge under safelight, and others claimed that they could only see it when a few drops were sacrificed on a glass slide and brought into the light. At the time I joined Kodak, they had ceased using this method about 30+ years earlier when the controlled digests and dual runs went into effect.

Also, for the pages Kirk gives, there is not much to see there, as he talks of the methods in general terms for the most part. I would not try to make a photograde colloid using his instructions, such as they are. They are mainly guidelines.

PE

I see.

Thanks Ron.

Struan Gray
08-29-2008, 05:08 PM
I am deeply interested, but do not really have the mathematical skills to comprehend it very well!

One of the tough things about the subject is that theoretical descriptions are full of assumptions and simplifications, just to make the problem tractable. On the other hand, it leaves plenty of room for experimental discoveries. :-)




Actually, there HAVE been several related photographic procedures that seem to use this principal.

I have a small file on this method of color photography as I am planning some experiments in that area... I don't think I was aware of the Science article...

.........

What is your interest in this subject?
(if you do not mind my asking)


My interest is partly professional: I work in a physics department looking at the links between the electronic properties of nanostructures and their physical properties, particularly friction. The electronic structure is what determines the optical response in the visible region and there are a whole raft of reasons why I have been trying to at least keep up with the literature. Mostly I want to use simple optical microscopy to characterise a dispersion of different nanoparticles, rather than having to resort to more complex and finicky electron or probe microscopes; but also because the optoelectronics are an essential part of any applications of my work, and so much of the froth around funding and status in science departments these days revolves around patents and commercial spinoffs.

Also, I think the subject's cool :-)

Also, I would like to do ULF colour, and I can't see myself ever affording my favourite colour emulsions in 12x15 or 15x15 size.

All the photographic work I have seen has been with AgCl emulsions. There was a lot of excitement in the early days of spectral recording onto AgCl on bare paper when people often observed colours, which in some cases seemed in direct correspondence with the colour of the light from the relevant part of the spectrum.

Bensley's method is a sort of bichromic one that builds on this. He resensitized a positive print made from the orange-red part of the spectrum and re-exposed in register with a negative made with the green-blue part of the spectrum before finally giving a slow, physical development. The existing grains of the positive image provide a template for the growth of AgCl crystals in the resensitisation step, and simultaneously mask the exposure, so they influence the size, shape and position of the silver grains formed in the final step.

It's not mentioned by the references I gave earlier, but once the nanoparticles get within a few diameters of each other their optical fields interact and you get a combination of a colour shift and a much stronger scattering. I'm intrigued by the idea that Bensley has made an all-silver image display colours not so much by tuning the size or shape of the silver grains, but by varying the spacing of the silver grains resulting from the second development. I suspect things are more dull, and he has produced a sort of Retinax pseudo-colour by mixing red and green monochrome images, but it's intriguing enough that I have started to assemble filters and film for some initial tests. The work gets shunted onto the back burner all too often though, so I'd love to hear of anything anyone else tries.

Photo Engineer
08-29-2008, 05:24 PM
Struan;

Many years ago, an early photographer made a color photo by placing a silver halide glass plate in contact with a pool of mercury which then set up diffraction rings in the coating. By proper illumination, the developed image was able to reproduce the original colors. I am not sure I remember who did it, my memory is faulty on this one, but they reportedly have one at George Eastman House but cannot diiplay or recreate it due to the use of an open pool of mercury. However, I think it should be possible to do by other means.

PE

Ray Rogers
08-29-2008, 08:49 PM
Struan;

Many years ago, an early photographer made a color photo by placing a silver halide glass plate in contact with a pool of mercury which then set up diffraction rings in the coating. By proper illumination, the developed image was able to reproduce the original colors. I am not sure I remember who did it, my memory is faulty on this one, but they reportedly have one at George Eastman House but cannot diiplay or recreate it due to the use of an open pool of mercury. However, I think it should be possible to do by other means.

PE

Hummm....

Ron,

Are you thinking of Gabriel Lippmann?
The Nobel Prize winning color photographer/physicist?

Gabriel Jonas Lippmann (August 16, 1845 – July 13, 1921)
(according to wiki... which also has a (poor?) example of it!)

I have seen several good examples of his process!

It produces the colors by interferance

(which to me is only vaguely understandable as something similar to a visual doppler effect... uh huh, uh, well anyway)

It can produce strikingly vivid and accurate colors.

It has some followers and wannabes (like myself), but there are servere difficulties with the procedure which keep it from being given the true respect it deserves.

I do believe it's day will come again!

BTW, the images can be viewed rather easily,
and can be also made without the Hg.

There used to be special camera backs sold commercially just for this sort of emulsion.

Ron, is it possible you had something else in mind?

Ray

Photo Engineer
08-29-2008, 08:54 PM
Interference is the correct word Ray. I was having another senior moment. This is what I had in mind, but GEH has some and they do not show them as they cannot use mercury. So, if you can suggest another method, this will do much of what Struan has posted.

PE

Ray Rogers
08-29-2008, 10:02 PM
One of the tough things about the subject is that theoretical descriptions are full of assumptions and simplifications, just to make the problem tractable. On the other hand, it leaves plenty of room for experimental discoveries. :-)

...it's intriguing enough that I have started to assemble filters and film for some initial tests. The work gets shunted onto the back burner all too often though, so I'd love to hear of anything anyone else tries.

Struan;

Yes.

It is very interesting!

Things behave sort of strange when very small!*

I think I will pull out my notes from what I read last year and see if you can make any sense out of them for me!

While different from what you described, let me just mention that if anyone reading this happens to know what happened to, or the whereabouts of a Joseph Boudreau, I would still like to contact him.

Joseph Boudreau had doing some work with Color Daguerrotypes the last I heard, but it seems he moved or something.....

Ray

*
Did they bend Laser Light?:

Have you seen or read about how laser light can be bent as it travells through a special (< 1nm) nanotech plastic? I just caught a glimse, but it looked like they digitized the analog curve so that laser light can be made to appear to bend.

Ray Rogers
08-29-2008, 10:44 PM
Interference is the correct word Ray. I was having another senior moment. This is what I had in mind, but GEH has some and they do not show them as they cannot use mercury. So, if you can suggest another method, this will do much of what Struan has posted.

PE

Considering Struan's field, I would imagine he is aware of Lippmann's work, but perhaps not.

Martin, who also posts here occassionaly, can fill us in on more about Lippmann Photography, including the current status of a list devoted to it.

Ron - Don't worry about that little 'moment'... I was about to scream EUREKA! when, while reading Herschel's hand written notes, it became obvious that Herschel had observed and described the beautiful and amazing vivid colors that could be produced by interferance... He wrote:

" For a remarkable production of color by diffraction see [...]
This is an most singular phenonomon "

I was thinking he had beaten Lippmann by decades... that was untill I said to myself: "NO! No way people could have missed such an important thing!" It took a few minutes but eventually I saw "diffraction" where once that "interference" had been so crystal clear!

Hummm...

OK, well now I am confused myself... again!

Two works:

Improvements in the Diffraction Process of Color Photography
Herbert E. Ives
(1906)
-----------------------------------------
Three-color Interference Pictures
Herbert E. Ives
(1907)

I think Martin could straighten this out...

Perhaps you are not as old as you think!

Ray

Hologram
08-30-2008, 05:04 AM
Colloidal silver can be almost any spectral colour. By varying the size and shape of a silver nanoparticle you can adjust the peak of it's reflectance right across the visible spectrum. It's a hot topic in current nanoscience.


Silver concentration may be another thing to consider. E.g. a dry gelatin layer with colloidal silver may appear red, whereas the same layer, wet, may be yellow.

Hologram
08-30-2008, 05:07 AM
Considering Struan's field, I would imagine he is aware of Lippmann's work, but perhaps not.

Martin, who also posts here occassionaly, can fill us in on more about Lippmann Photography, including the current status of a list devoted to it.

Ron - Don't worry about that little 'moment'... I was about to scream EUREKA! when, while reading Herschel's hand written notes, it became obvious that Herschel had observed and described the beautiful and amazing vivid colors that could be produced by interferance... He wrote:

" For a remarkable production of color by diffraction see [...]
This is an most singular phenonomon "

I was thinking he had beaten Lippmann by decades... that was untill I said to
myself: "NO! No way people could have missed such an important thing!" It took a few minutes but eventually I saw "diffraction" where once that "interference" had been so crystal clear!

Hummm...

OK, well now I am confused myself... again!

Two works:

Improvements in the Diffraction Process of Color Photography
Herbert E. Ives
(1906)
-----------------------------------------
Three-color Interference Pictures
Herbert E. Ives
(1907)

I think Martin could straighten this out...

Perhaps you are not as old as you think!

Ray

There is a forum on Lippmann photography at http://holographyforum.org/phpBB2/viewforum.php?f=14&sid=d4d8bac3e4339dbf5ae83dbd44457e34

We tried to put together a collection of classic papers related to Lippmann photography - see:
www.holowiki.com/index.php/Lippmann_Papers (that site is temporarily down but principally I can send you any of these papers - just give me a PM). Most of these papers are written in French and German (probably for some historic reasons the English speaking world seemed to have ignored Lippmann photography to a large extent).

Hologram
08-30-2008, 05:17 AM
Alright, then. It's decided. If I ever completely lose my mind and decide I need to make colloidal silver myself, it will be with a hand cranked centrifuge!

:) Actually...you know...if I set things up right, when we lose power here in the winter for days at a time, I could still make emulsions. Bunsen burner, hand whisk, gaslight. Just kidding (I think).

There might be easier ways of making colloidal silver. For example, adding a small amount of a reducing agent to a AgNO3/gelatin solution does form colloidal silver. A simple way of doing this is adding ascorbic acid to the above solution. The size of the silver particles depend on different parameters: silver/gelatin/reducer concentration, temperature, time...

Ray Rogers
08-30-2008, 07:48 AM
Silver concentration may be another thing to consider. E.g. a dry gelatin layer with colloidal silver may appear red, whereas the same layer, wet, may be yellow.

Yes. I am not sure if it is due to dilution or solvation or both, or hallucination, but I do see color changes as (non-lippmann) emulsions are diluted.

Struan mentions this when he writes "once the nanoparticles get within a few diameters of each other their optical fields interact and you get a... colour shift...I'm intrigued by the idea that Bensley has made an all-silver image display colours not so much by tuning the size or shape of the silver grains, but by varying the spacing of the silver grains resulting from the second development."

Perhaps someone could devise a color photographic system based entirely on dilution and or swell?

Photo Engineer
08-30-2008, 09:03 AM
In suspensions of fine particles, if you stir them, you often see what appears to be swirls in a moire pattern of colors. This is presumably due to the effect Struan mentions. We see this sometimes in chemical preparations when an ultra fine precipitate is present.

PE

Kirk Keyes
09-02-2008, 12:23 AM
while reading Herschel's hand written notes[...]

I was thinking he had beaten Lippmann by decades... that was untill I said to myself: "NO! No way people could have missed such an important thing!"

Herschel did discover the fixing properties of thiosulfate which went un-noticed for about two decades.

Sir John Herschel was an amazing person. Although that's not too surprising, considering who his father was, Sir William Herschel who discovered the planet Uranus, and his aunt Caroline Herschel, who devoted her life to assisting John's father in his observations, and rightly discovered several comets on her own.

Kirk Keyes
09-02-2008, 12:29 AM
Ray - re google books.

Are you in Japan? What browser are you using?

Your browser issue reminds me of when I was in Mexico a few months ago. Google refused to let me see the regular www.google.com and forced me to www.google.mx.

I really like google books - it's got some pretty interesting stuff there. Especially historical stuff. I can see the entire page, and even download the books that have the links I gave. They have some stuff that have "snippet views" which just annoy me as they obviously have the entire text scanned in but they are trying to avoid copyright infringement by not showing you more than a line or two of the text.

But there's a lot of interesting stuff there and I suggest you keep trying t find a way to get it to work. I've bought several books that I've seen either the full text or bits of it on google books.

Ray Rogers
09-02-2008, 01:15 AM
Herschel did discover the fixing properties of thiosulfate which went un-noticed for about two decades.

Sir John Herschel was an amazing person. Although that's not too surprising, considering who his father was, Sir William Herschel who discovered the planet Uranus, and his aunt Caroline Herschel, who devoted her life to assisting John's father in his observations, and rightly discovered several comets on her own.

Yes.

I tried to follow the hint but the meaning of some code numbers need follow up to confirm exactly what Herschel was referring to... I will have to open up that folder and finish following the lead.

I agree- He was amazing... I have a lemon soda formula of his I am dying (from the thirst of curiosity) to try!

Ray Rogers
09-02-2008, 01:34 AM
[QUOTE=Kirk Keyes;675191]Ray - re google books.

Are you in Japan? What browser are you using?

Your browser issue reminds me of when I was in Mexico a few months ago. Google refused to let me see the regular www.google.com and forced me to www.google.mx.

They have some stuff that have "snippet views" which just annoy me as they obviously have the entire text scanned in but they are trying to avoid copyright infringement by not showing you more than a line or two of the text.
QUOTE]

Yes.

I guess the same thing is happening to me.
It seems the site decides to make you use the local (google?) system...
I can use either google, but the using the link I found only confusing semi related sentences, and honestly, I got so frustrated with- you guessed it those "snippit" strips of torn pages I lost the will to hunt... and have already forgotten what it was exactly.

Perhaps if I look again I will find a way out, but I am not hopeful.

I will try again someday, after I recharge.

Ray

Struan Gray
09-02-2008, 04:31 AM
I am sorry for my relative silence: I've been whooping it up in Legoland :-)

Colour is a big topic, but it is important to realise that there is a fundamental difference between interference colours such as those found in Lippmann emulsions and thin films, and the colours of colloidal silver which are related to excitations of the electrons in the silver particles, and are thus more like the colours of pigments or dyes.

Interference colours can be very intense and pure, but they generally only work over a limited range of angles. Exceptions exist which work over wider angles - the canonical example is the pure blue of the Morpho butterfly wing - but as I understand it Lippmann emulsions only display their correct colours when viewed head-on.

I think holographic emulsions are today's direct descendents of Lippmann's work: they perform a similar task of preserving interference fringes in the thickness of the emulsion by laying down correctly spaced lamellea of silver.

In metallic materials where the electrons are free to move you can create compression waves in the sea of free electrons which are analgous to sound waves in a gas. These are the so-called 'plasmons' which crop up as buzzwords in any modern discussion of the optical properties of small metallic structures. Because the wave changes the local charge density, it has an associated electromagnetic field, and in the right circumstances you can couple that field to the freely propagating plane waves of which light is made.

It is these plasmon modes which give colloidal silver its colour. Other metals work too: gold for example turns red and then a gorgeous deep blue as you make smaller and smaller particles. Most experiments are done on noble metals because the large surface area to volume ratio of the particles makes them very susceptible to corrosion and oxidation, but in principle aluminium and iron will display similar effects.

The plasmon frequencies are acutely sensitive to the particle's size, shape and local environment. As I said in my earlier post, nearby particles can radically change the way that a particular particle scatters light, but the properties of the surrounding medium can have a similarly dramatic effect: changes in its refractive index or its pH will often lead to changes in colour.

This sensitivity is one reason for the widespread interest in applications of plasmonic structures. For example, you can already buy blood sensors where the binding of a protein to a gold film changes the plasmon frequency and alerts a monitoring circuit. It is also the reason that plasmonics seems to promise a tempting wide-tunability across the optical spectrum.

The problem for photographic applications is that the same sensitivity makes the colour production unreliable, especially with conventional home darkroom levels of control and repeatability. If time, temperature, humidity, and chemical concentations have to be controlled to 0.001% then this isn't a practical photographic technique, even if the same science ends up being used industrially to make sensors or the next generation of LEDs.

There are of course other mechanisms to make nanostructures more coloured than their bulk analogues. Mie scattering can be highly wavelength and orientation dependent, and the absorbtion that turns large chunks of material grey does not have a chance to work in small systems. Nanowires made from semiconductors show the most beautiful colourations, even in the absence of interference or plasmon effects.

I should stress that I am not a real plasmonics expert, although I do work with a few, and I have very little relevant experience of the photographic aspects of these phenomena. I very much welcome further discussion, and the valuable practical input from those who have actually got their hands dirty in a real way.

Final point: the early colour I was thinking of was bare AgCl on a paper support, as used by spectroscopists to investigate projected solar and other spectra by measuring the pyrolitic or photolitic darkening of the halide when exposed to a spectrum from a prism. Herschel reports on some of these colours in his huge catch-all paper in the Royal Society's Phil. Trans. from 1840 (the same paper where he reports the use of "hyposulphites" as a fixer), but I am sure many other early workers noticed and commented upon them. These are unlikely to be caused by an interference effect, and are most likely plasmonic colours.


Struan