I'm getting my "Autochrome" experiments going again ...

[Photo Engineer]

I have been doing some research myself for all of you interested in Autochromes. This information comes from J. S. Friedman's "History of Color Photography".

In it, he gives the fundamental US patent #s (411186 and 471187) and states that the preferred method used dyes dissolved in an organic solvent and shellac. The three dye solutions were evaporated and the solid dyed shellac was ground to a fine powder to give about 1200 particles / inch. The emulsion was 0.4 microns and was a blend of 3 emulsions, R, G and B sensitive. It was not a panchromatic emulsion.

He also describes the method of 'first black' and 'second black' in the design of a proper Autochrome.

Hope this helps.

PE

 

[htmlguru4242]

wait, so are you saying that the particle screen wasn't actually potato starch, it was shellac?

Also, Kino, I looked up that varnish; "benzol" is in fact Benzene (which nobody wants to play around with). But there's a lot of info. out there about making dammar varnishes. They reccomend use of turpentine, which is MUCH better.

 

[Photo Engineer]

wait, so are you saying that the particle screen wasn't actually potato starch, it was shellac?

Also, Kino, I looked up that varnish; "benzol" is in fact Benzene (which nobody wants to play around with). But there's a lot of info. out there about making dammar varnishes. They reccomend use of turpentine, which is MUCH better.

Html;

I am not saying it was anything really. I was quoting Friedman. And Friedman was quoting the preferred options in the US patents.

It may turn out to be that they started with starch and ended up with shellac or vice versa. IDK. Using shellac seems likely to me as a good way to dye the particles with water insoluable dyes and then coat them.

The method described for coating the shellac particles was the same as described above in this thread. The mixed powder was sprinkled on a tacky layer of varnish on the film support. The excess powder was blown away somehow.

That is a summary of about 10 pages in Friedman on Autochrome.

PE

 

[Donald Qualls]

Yes it went over the starch and the emulsion coated directly over that. You make the varish by dissolving three parts of "gum dammar in 1000 parts benzol", according to the book.

Now the "gum dammar" looks fairly benign, but the "benzol" looks uncomfortably close to benzine, so a different solvent might have to be sourced out.

At work now (naughty, naughty) and will try to respond tonight with better answers...

Frank

That actually sounds (allowing for slight changes in the way French was tranlated into English 80 years ago) like the damar varnish used by artists for oil paintings; that stuff is available, pre-mixed, in bottles ranging from a couple ounces to a gallon. It thins with turpentine, though you can clean it with benzene (however, benzine is a European term for what we now call gasoline, aka mineral spirits, similar to paint thinner -- an alternate for turpentine even in modern oil painting).

 

[Photo Engineer]

There is Ligroin and Petroleum Ether, both similar but boiling at different points I forget which is which, but they are not benezine.

They are saturated hydrocarbons. They are all 3 similar in properties.

PE

 

[Kino]

OK, I have the article in PDF form, but there is a problem...

Problem is it is 3 MB +...

Any ideas on how to get this to those who are interested?

It took 5 hours to OCR this damn thing...

 

[Kino]

That actually sounds (allowing for slight changes in the way French was tranlated into English 80 years ago) like the damar varnish used by artists for oil paintings; that stuff is available, pre-mixed, in bottles ranging from a couple ounces to a gallon. It thins with turpentine, though you can clean it with benzene (however, benzine is a European term for what we now call gasoline, aka mineral spirits, similar to paint thinner -- an alternate for turpentine even in modern oil painting).

Donald,

Well, that is good news! It would be nice to have the option to buy a few elements off the shelf.

Frank

 

[htmlguru4242]

Ah, thanks for scanning that stuff, Kino.

PM me and i'll help you get it smaller ....

 

[Petzi]

OK, I have the article in PDF form, but there is a problem...

Problem is it is 3 MB +...

3 MB is nothing these days.

 

[htmlguru4242]

I don't know if you can post 3mb attatchments, that might be why he's saying that.

Kino, you could put it in a zip file, or only put a few pages in each pdf and post it as multiple pdfs ....

Or just e-mail it to those who arte interested.

 

[Kino]

3 MB is nothing these days.

It is when there is a 2 MB limit on downloads in this forum...

 

[Q17]

Kino,

Is it possible to write the document to two PDF's? You could do a part A/B type thing.

=michelle=

 

[htmlguru4242]

OK, let's discuss the PDF stuff on another topic, let's get this back to Autochrome ....

I'm trying to dye some potato starch. I have some dying with food dye and some with sharpie ink.

How would fabric dye work for this purpose?

 

[Photo Engineer]

OK, let's discuss the PDF stuff on another topic, let's get this back to Autochrome ....

I'm trying to dye some potato starch. I have some dying with food dye and some with sharpie ink.

How would fabric dye work for this purpose?

All of the dyes you describe are water soluable dyes that are either very soluable in water or can be mordanted by the proper method / chemical.

It is possible that they will dye properly, but then if not protected during processing they will wash out in the processing solution. Of course, we have discussed this before. Of course, your screen will not be mounted during processing, but it has been pointed out to me that this causes a severe registration problem with an irregular array such as Autochrome. Regular arrays such as Dufay do not suffer as badly from that problem.

Anyhow, my eye was caught by the reference to using shellac and water insoluable dyes. This overcomes just about all of the problems you have mentioned so far. You dissolve the dye in an organic solvent along with shellac, evaporate the solvent and then grind up the shellac. You blend it to create a neutral and dust it onto a sticky surface. And, if done properly, the screen can be integral with the emulsion.

Have you looked at those two patents? They may contain a lot of hints for you. Friedman does mention the starch method, but essentially goes on to devote space to the shellac method as the preffered one. I wonder if he knew more than we do right now, and that we have been misled by the comments about starch.

Just a thought, as I really have no idea at all.

BTW, one of the individuals that I referred you to recently made a Dufaycolor type material. He showed me the results and they were quite good considering the size of his array. We could move the array around and watch the colors shift in and out of sync with reality. The screen and the film were mounted on separate supports. I believe he used waterproof marker. However, the screen didn't go through the process.

PE

 

[htmlguru4242]

I've gotten a process with a line screen working as well, similar to Dufay in a way, but with straight lines.

I'n not going to coat the dyes over the emulsion; my first try is ging ot be to cement a piece of sheet film to a glass plate, and see how that works, so I guess that dyes that are water - soluable will not be a problem. Can you let me know which contact just made hte Dufay material?

 

[Photo Engineer]

I've gotten a process with a line screen working as well, similar to Dufay in a way, but with straight lines.

I'n not going to coat the dyes over the emulsion; my first try is ging ot be to cement a piece of sheet film to a glass plate, and see how that works, so I guess that dyes that are water - soluable will not be a problem. Can you let me know which contact just made hte Dufay material?

Mark made the Dufay analog. He showed it to me a few weeks ago and also showed me a 1880s tricolor set shot through separation filters using chlorophyll and erythrosin as sensitizing dyes.

He used straignt lines also.

PE

 

[htmlguru4242]

That's interesting, PE, was the Chlorophyll used as a sensitizing dye in the emulsion?

 

[Photo Engineer]

That's interesting, PE, was the Chlorophyll used as a sensitizing dye in the emulsion?

Yes, it was. That is an old, well known technique.

PE

 

[htmlguru4242]

Wow, PE, that's interesting ... would that still work? because, it so, it suddenly makes panchromatic sensitization SO MUCH cheaper ...

 

[Photo Engineer]

Wow, PE, that's interesting ... would that still work? because, it so, it suddenly makes panchromatic sensitization SO MUCH cheaper ...

I'm not THAT old, lol. I really don't know how to do it as I have not read up on it myself. I have no idea how it works and how well it works. All I know is that it will sensitize in the 'anti green' region of the spectrum. It is NOT a green sensizer, more like a reddish sensizer. It is not even a red sensitizer, per-se.

It must be extracted and purified for use. The methodology is known by Mark, AFAIK.

PE

 

[htmlguru4242]

Ok, PE, I'll ask mark about that.

I have a newly dyed set of starch at home, soon to be coated on [yet] another plate.

This time, I'm going to try a mixture that's closer to the original. I'm aware that it was pitch and beeswax, but does anyone have any idea about what proportions?

And Kino, you can send that scan to htmlguru4242@charter.net when / if you can. Thanks

 

[htmlguru4242]

I'm going to coat tonight; I'll let everyone know how it goes.

 

[Ole]

Any updates on this?

I recently bought a set of lenses which included a set of filters. One of them was an "Autochrome filter" - brownish orange. I assume that was to compensate for the sensitivity differences with the coloured starch grains?

 

[htmlguru4242]

Yep, that filter is to cut down on the blue light from the scene, in order not to overexpose the blue portion of the image. I'm assuming that the original emulsion was not very sensitive to the red end of the spectrum, so this filter'd help.

As to progress, this has been on the back burner for awhile, though I got an ok coating of starch on a plate.

Soon, however, I'll have a set of 2 4"x5' Autochrome plates, which have been exposed to room light (emulsion is toast, then), but I hope it'll give me some insight into a real plate (I've never seen an undeveloped one).

 

[holmburgers]

I realize that this post has been dead for about 3.5 years, but is anyone still working on this?

I have been dreaming about making Autochromes for some time, but just learned that Dufaycolor is principally the same or very similar.

Has anyone attempted to make a reseau (screen) by photographing a white television screen with slide film? It seems like this, or a similar concept, might greatly simplify the making of the filter screen.

Anyways, if any of you are still alive and kicking, PM me or just post.

Thanks!