So just how hard can it be to make film?

[eumenius]

I once coated myself some wet collodion plates for our scientific work - and they worked quite well, being 60x75 centimeters big! Both continuous tone and line plates were made in our lab without much effort, so it's not a problem I got notes about it somewhere in my workbooks, so I can post it here if someone is interested

Cheers from Moscow,
Zhenya

 

[avandesande]

In the old times they just laid a huge sheet of acetate on the table and poured the emulsion on it. Making multiple layer films this way is impossible but a single layer is not too bad. Super xx was the last single layer film, which is what many of us LF people want anyway.

I dont see any pollutant 'side streams' from this process either.
EK probably made most of their raw materials and this would explain the pollutants. Somebody doing this in their garage would be buying all their starting materials.
The dyes used to sensitize the emulsion are well known.

 

[Dave Wooten]

Question to the mentioned topic if Kodak ceased all production and kept their formulas "secret"

1. Are the formulas protected by patent?

2. Isn't one of the requirements for patent protection that the patent be used? That is you can not be awarded a patent and just sit on it......

3. It shouldn't be that difficult for formulas to be duplicated?

4. Would it be cost effective and would other companies step up to the plate even if the most popular formulas were available....

 

[avandesande]

Patents are only good for 17 years.

 

[Jorge]

The dyes used to sensitize the emulsion are well known

Do you know where I can find this information? If you have checked it out, do you know if they are terribly expensive?

 

[avandesande]

Here might be a place to start... you will find tons of stuff in the patent literature.

Just type the patent numbers in the quick search...

http://patft.uspto.gov/netahtml/search-bool.html

The following is from something I found on google just now....
Further, various chemical sensitization methods which are commonly applied to usual emulsions, may be applied to the emulsions of the present invention. Namely, chemical sensitization agents, for instance, active gelatin; noble metal sensitizing agents such as a water-soluble gold salt, a water-soluble platinum salt, a water-soluble palladium salt, a water-soluble rhodium salt and a water-soluble iridium salt; sulfur sensitizing agents; selenium sensitizing agent; or reduction sensitizing agents such as polyamines and stannous chloride, may be used alone or in combination for the chemical sensitization. Further, the silver halide can optically be sensitized to have a desired wave length. There is no particular restriction to the method for optical sensitization of the emulsion of the present invention. For instance, optical sensitization agents, e.g. cyanine dyes or merocyanine dyes such as a zeromethine dye, a mono-methine dye, a dimethine dye, and trimethine dye, may be used alone or in combination (e.g. for super dye sensitization) for the optical sensitization. Techniques for such optical sensitization are also disclosed, for instance, in U.S. Pat. Nos. 2,688,545, 2,912,329, 3,397,060, 3,615,639, 3,397,060, 3,615,635, and 3,628,964, British Pat. Nos. 1,195,302, 1,242,588 and 1,293,862, German Patent (OLS) Nos. 20 30 326 and 21 21 780 and Japanese Patent Publication Nos. 4936/1968 and 14030/1969. The selection may be optionally made depending upon the particular application or purpose of the light-sensitive material, such as the desired wave length for sensitization, or the desired sensitivity........

Sourcing speciality chemicals is a tricky business. If you follow the M&P forum you will see that a bunch of people bought a bunch of amidol really cheap from china. You can start with google.

Feel free to contact me via private message, I used to work in the chemical industry and sourced stuff all the time.

I would make film but I only have enough time for taking pictures.

 

[avandesande]

http://www3.interscience.wiley.com/cgi-bin/summary/107642442/SUMMARY

 

[Jorge]

Thanks Aaron, I am glad all the info is out there, just a matter of wading through the theory...

 

[avandesande]

The wiley book will help you the most. It tells you exactly what is used by the industry and also a chapter on manufacturers.
Patent literature is much more vague, and unless you have a chemistry background, incomprehensable.

 

[Jorge]

The wiley book will help you the most. It tells you exactly what is used by the industry and also a chapter on manufacturers.
Patent literature is much more vague, and unless you have a chemistry background, incomprehensable.

I might just get the book to keep just in case. It has been a looooong time since I did any organic chemistry and as you say what I saw of the patent lit was though reading..

 

[Jorge]

LOL...well on second thought at $285 a pop I think the book is going to have to wait....

 

[Ian Grant]

Actually as someone who patented a photographic process / emulsion there is not much you can really do in practice as very small differances would get around it.

For easons of commercial secrecy companies don't publish their formulae.

The best (and only) source of good published emulsion formulae was made available after WW11 by the Allies when they translated all the Agfa Gevaert formulae. The books are quite difficult to get hold of, I employed a consultant in the 70's who happened to be related to the Lumiere family, (of Autochrome fame) and had acquired their copies.

These books went into great detail of all the manufacturing and coating techniques, I copied what I needed at the time.

Ian

1. Are the formulas protected by patent?

 

[dancqu]

Can film be produced with sufficiently affordable equipment
that one could start with a small operation and then grow
it over time if demand required? Where would one start?

I think that world wide there must be scores of small
producers, nitch producers, of silver gelatin films. IIRC, films
for our purposes began to be manufactured and offered to the
public around about the 1880s. Kodak then marketed their first
send it all in the for processing and reload, camera and film.

For starters do a search for historical information on the
manufacture of film. Now, 125 years after those beginnings,
much research has been done, much equipment invented,
and much of that, I dare say, is available in today's form
at huge discount. Now days there is no having to coal
the boilers. A snap to do, don't you think? Dan

 

[Ian Grant]

If you had to you could try these for starters

1, 1'-diethylcarbocyanine chloride (was marketed as sensitol red in the 1930's)

or 2-p-dimethylaminostyryl-pyridine methiodide

Both found in 1930's publication and with referance to Eastman Kodak Research laboratories.

Do you know where I can find this information? If you have checked it out, do you know if they are terribly expensive?

 

[fhovie]

apugpan -

can be pushed 14 stops - can capture details on the sun and moon during a partial eclipse - 35mm version can be blown up to 48 x 60 INCHs without grain. Very high accutance. Good red sensitivity. Available in ALL formats from 16mm to 16x20.

$1 per roll
100 sht box of 8x10 - $25

What do you think???

 

[Photo Engineer]

Most of the emulsion formulas from before 1940 are very primitive and involve some rather tricky steps. Recent ones published in patents are quite different and just as difficult but in a different fashion. For a good example of a modern emulsion see US Patent 6,524,782. This is a modern t-grain make.

Even if the average person could make a good emulsion, coating it well for in camera or paper printing use would be difficult. Finding the right film support or paper support would also be difficult, as you must have the right substrate to coat on or you get poor adhesion or desensitization. Anyone out there know how to get plain baryta paper with no emulsion on it?

Another sensitzing dye sometimes used in the 40s and still available is Erythrosin, or tetra iodo eosin. This was reported in early work by Eastman Kodak and other companies as a good ortho sensitizing dye. It is still available and is not overly expensive when you consider the amount needed to sensitize an emulsion.

PE

 

[avandesande]

http://silvergrain.org/Photo-Tech/literature.html

http://www.amazon.com/exec/obidos/A...35532/sr=11-1/ref=sr_11_1/104-2353793-1649551

 

[avandesande]

If you find something you want look it up at the sigma/aldrich site. It will give you a rough idea on pricing

http://www.sigmaaldrich.com/catalog/search/AdvancedSearchPage

 

[avandesande]

where would we be without the web???

Dead Link Removed

http://www.reuels.com/reuels/page440.html

 

[Jorge]

Now that is more like it, the book can be had used for a great discount....Thanks Aaron!

 

[donbga]

Anyone out there know how to get plain baryta paper with no emulsion on it?


PE

According to Christian Nze, Bergger sells plain baryta paper with no emulsion.

Good luck,

Don Bryant

 

[avandesande]

Hurry up and order one. I couldn't help myself.

Now that is more like it, the book can be had used for a great discount....Thanks Aaron!

 

[Photo Engineer]

where would we be without the web???

Dead Link Removed

http://www.reuels.com/reuels/page440.html

Thanks for the quick reply, however I should have noted that the transparent support for coating must be subbed or the gelatin will not spread or adhere. Only a few companies do this. Jim Browning has published one source for that type of support, but it is only available in large rolls.

The same is true for RC paper support. It must have a titanox layer, resin and then a subbing layer for adhesion.

The baryta from Bergger will be usable, if available. I hope I can get it in less than master rolls.

PE

 

[avandesande]

What does 'subbed' mean (as far as acetate film is concerned)?

 

[avandesande]

Similar to this....??

The polymers per se disclosed in U.S. Pat. No. 3,501,301 are particularly preferred for operation in accordance with this invention. The most preferred polymers for use as a subbing layer in accordance with this invention are a terpolymer of vinylidene chloride, acrylonitrile, and acrylic acid and a copolymer of vinylidene chloride and acrylonitrile.

It is a requirement in accordance with this invention in order to solve the problem of blisters, outlined above, that the subbing layer be applied from an organic solvent solution. Any suitable solvent for applying the subbing layer to the substrate may be employed such as, for example, dichloromethane, ethyl acetate, methyl ethyl ketone, trichloromethane, carbon tetrachloride, ethylene chloride, trichloroethane, toluene, xylene, cyclohexanone, 2-nitropropane, and the like. Dialkyl ketones, for example, acetone, methyl ethyl ketone, diethyl ketone, methyl propyl ketone, methyl isopropyl ketone and the like are preferred. Methyl ethyl ketone is most preferred. Alcohols such as methanol, ethanol, propanol, butanol, isopropanol, and the like may be used in mixture with the above-mentioned solvents. In applying the subbing layer to the substrate, the ratio of polymer to solvent is not critical; however, the polymer to solvent ratio employed is preferably from about 0.1 to about 10 percent by weight. The subbing is then dried to remove the solvent and the antistat layer is next applied to the subbed film support.