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Photo Engineer
04-26-2008, 07:52 PM
Must... not... debate... practice vs. patents here. (That was my best Shatner imitation there.) Let's start another thread then. Actually, I think that was done a week or so ago.

But if you want to take this one and discuss the patent vs. the practice of this specific practice, I'm all for that.

Yes, I started a patent thread where we could discuss issues like this, and it died.

PE

David A. Goldfarb
04-26-2008, 08:33 PM
Okay, now that everyone's gotten off their chests the notions that patents can be ridiculous, misleading, and don't always reflect real practice, I think Kirk's original idea was a good one--let's make this thread a reference list of patents relating to emulsion making.

Ideally posts should have a link to the patent or the text of the patent, if it's very short, and a brief description or at least a title.

If you want to discuss the patent in question, please start a separate thread for the purpose, as was done for the ISO washing patent. If you're clever about it, you can even include a link to the discussion thread in your reference post for this thread. Try opening a new tab in your browser for the new thread before closing the reference in this thread, or post the discussion thread first, copy the URL to your clipboard, and paste the link to the discussion thread in your reference post in this thread.

rmazzullo
04-26-2008, 10:52 PM
This thread started last July by Photo Engineer listed 4 very informative patents, and for some strange reason, aside from my response, the thread was completely ignored. If you look closely at the second patent listed, it shows how to make a graded iodide t-grain emulsion in very clear detail. The secrets are right in front of you, folks. It's all here, and has been since July of 07. Right on a silver (halide) platter. Hiding in plain sight, as it were.

http://www.apug.org/forums/forum205/40516-those-interested-patents.html

Look what else PE shares about the second patent: "I worked with one of the inventors during the development of this type of emulsion, when I was working on the emulsion design program and model."

If the information and what it means was any clearer it would bite you on the ass. It's interesting how everyone who 'wants information' , and 'please share what you know' etc, etc, somehow completely ignored or overlooked this thread. Perhaps we were too busy paying attention to other self described 'experts' who still...TO THIS DAY....haven't posted a single piece of evidence to back up their claims.

Are you awake yet?

Bob M.

Neanderman
04-26-2008, 11:31 PM
A long URL:

http://patimg1.uspto.gov/.piw?Docid=01574944&PageNum=&Rtype=&SectionNum=&idkey=NONE&Input=View+first+page

Sheppard, "Photographic light-sensitive material and proces of making the same." 1926.

Sulfur sensitization. Still widely referenced.

Kirk Keyes
04-27-2008, 12:13 AM
Sheppard, "Photographic light-sensitive material and proces of making the same." 1926.

Sulfur sensitization. Still widely referenced.
Any ideas on how to print these out? It's a quicktime video or something...

Kirk Keyes
04-27-2008, 12:17 AM
PE's post from the thread linked to above:


I have been asked a lot about the patents related to film making and coating, so here are some of the ones you might find quite interesting.

1. Coating - USP 2761791

This discloses slide coating and shows the design of several types of coating hoppers in current use. Unless upgraded with rather expensive equipment, second and third tier companies do not use these types of hoppers.

2. Emulsion Making - USP 5132203

This shows how to make a graded iodide t-grain emulsion. I worked with one of the inventors during the development of this type of emulsion, when I was working on the emulsion design program and model.

3. Dopants in Films - USP 5360712

This describes what chemicals are added to modern films to get good speed, curve shape, latent image keeping and reciprocity failure. (that is if you follow the crumb trail laid out here)

4. Color Films - USP 5302499

This describes the organic chemicals and emulsions needed to assemble a modern film. It is up to you to pick out the useful chemicals (wheat from the chaff) and to follow the trails again laid out.


There are a lot more patents than this, such as those describing control methods, algorigthms, process control equipment and mixers to name a few but this is enough for now. It pretty much covers all aspects of film making from start to finish.

Remember, a patent only needs to disclose what will help a person "skilled in the art", and so a patent can mislead you if you do not understand the basic underlying principles, or if you don't follow the numberd dots.

This has been a particular difficulty trying to explain photographic engineering sometimes.

Enjoy.

PE

I see I was at the beach for a week when this was posted...

Kirk Keyes
04-27-2008, 12:25 AM
http://www.google.com/patents?id=xDlFAAAAEBAJ&dq=2761791

http://www.google.com/patents?id=EpooAAAAEBAJ&dq=5132203

http://www.google.com/patents?id=0GwaAAAAEBAJ&dq=5360712

http://www.google.com/patents?id=djUpAAAAEBAJ&dq=5302499

Kirk Keyes
04-27-2008, 01:14 AM
So does anyone have a good patent to look at for sulfur + gold sensitization?

rmazzullo
04-27-2008, 06:42 AM
Any ideas on how to print these out? It's a quicktime video or something...

This is a link to a tiff file (image file) on the uspto.gov web site. Go to www.alternatiff.com and install the free web browser plug-in to view tiff files. It is an active-x control so you may have to temporarily open up your security settings to install this (if you have AV / AS / Firewall software installed).

Once installed you can print out the paper page by page....

--OR--

go to www.pat2pdf.org and enter the patent number (1574944) and download the whole thing as a pdf. Save it, then print the whole thing at once, or just print it.

--OR--

go to google.com, enter the patent number and download and / or print from there.

Sometimes, pat2pdf has better copies of patents than google does.

Bob M.

Kirk Keyes
04-27-2008, 09:04 AM
Bob - thanks. But did you try google patents, or are you just assuming it's there? I don't find it in the first several pages there so how many pages does one need to go to find it...

www.pat2pdf.org works wonderfully.

Photo Engineer
04-27-2008, 09:11 AM
I would like to point out that some of these patents refer to either Research Disclosures or Defensive Publications which are used to further obscure the 'bread crumb trail'. And DPs are hard to get at. RDs are fairly easy to get.

PE

Photo Engineer
04-27-2008, 09:12 AM
Use www.freepatentsonline.com and set up an account.

You see either the text (without an account) or either that or the pdf file with an account.

PE

rmazzullo
04-27-2008, 10:18 AM
Bob - thanks. But did you try google patents, or are you just assuming it's there? I don't find it in the first several pages there so how many pages does one need to go to find it...

www.pat2pdf.org works wonderfully.

My bad. Sometimes, for some reason, a particular patent is not available on the google server, but available on the pat2pdf server. In this case, I had to drill down to patent 7220537 to find a link to 1574944. Then I found out it wasn't available. But patent 1623499 (also by Sheppard) and cited by 7220537 does refer to 1574944, and it (1623499) is visible on google.

Six of one, half a dozen of the other.

Bob M.

Ryuji
04-27-2008, 01:17 PM
Yutzy et al patented a few different implementations of acid coagulable gelatins and method of making emulsions using the same. His patents have some omission in the area of how the acid should be added. There is an art in the gelatin-to-silver ratio, temperature, stirring, and other secondary coagulants used in conjunction with this method. Depending on how you add these things, the emulsion coagulum may come out like big chunks or tiny granules. Of course, the latter is better for complete washing, but then the granules take longer time to settle after the first wash cycle. As you see, the desalting stage is a big chunk of proprietary know-how and not very fully described in patents, and this topic is also rarely discussed in academic literature either. But these things, if you have sufficient knowledge and experience in photographic chemistry, you can try them and fill in the missing parts by experimentation.

For Yutzy's acid coagulaion methods, see 2597915, 2614928, 2614929, 2718662 and compare.

In my experience, the coagulation method disclosed in Roth, US Patent 3118766 is superior. It coagulates more easily, enhances adhesion of the emulsion, and the yield of acylation reaction is more complete within the desirable pH range.

One big difference in terms of ease of using these techniques is that phthalic anhydride must be first dissolved in a suitable water miscible solvent like acetone, while trimellitic anhydride can be added to the water phase directly, as the latter is water soluble. Another big difference is that the pH range required for the acylation reaction. Trimellitic anhydride can react faster, even at a lower pH. During the acylation reaction, the pH slowly drops, and you can't use common buffering agents (despite the agents listed in the patents) because these are nucleophilic reactions and the buffer will likely interfere. So you will have to have the pH maintained in the usable window by addition of NaOH or KOH while monitoring the pH and temperature. A wider reaction pH window of trimellitic anhydride makes this process quite a bit easier.

On the problem side, these acylatin-in-emulsion methods are incompatible with ammonia ripened emulsions, because these acid anhydrides will react with the ammonia faster than gelatin. I personally do not use ammonia as the ripener (it smells very bad unless your emulsion making setup is in a fume hood---my lab is on 250cfm ventilation but I don't like the smell) and ammonia also increases fog level very much. One way to make them compatible is to use acylated (i.e., phthalated or trimellitiated) gelatin from the beginning. This technique is actually very useful for making tabular grain emulsions, but not conventional cubic or octahedral emulsions. Fog level, contrast and grain shapes are affected.

On the other hand, if you use phthalated/trimellitiated gelatin from the beginning, your nucleation pH is inevitably higher than pH of 5.5, to stay out of the range where gelatin starts to coagulate. This is problematic in making low fog emulsion of good contrast. In order to make good emulsion, I often have to adjust the pH and temperature after nucleation but before growth stage, and pH of 3 is definitely preferred for nucleation for most emulsions. Phthalated gelatin in presence of salt coagulates at pH 3 and is unusable.

Another problem, a real practical problem, is that these acylated gelatins do not harden with common organic hardeners AT ALL. If you use these hardeners, you must keep the proportion of the acylated gelatin low, and add a non-acylated gelatin after washing stage. This makes gelatin-to-silver ratio too high. Of course, there is work of Yudelson, US Pat 3017280, and more, but these agents are very nasty to make, and many are nasty to use.

I have tried all these methods and came to a conclusion: keep trimellitiated and phthalated gelatin for tabular grain purposes, and for subbing purposes.

For conventional emulsion work, I use more convenient polymer coagulation method. See De Pauw US Pat 3884701. This method is very much easier to use, and superior in many ways. The problem is that the polymer described in this patent is not commercially readily available, although it is not very difficult to make from styrene and styrene sulfonic acid, with AIBN or other starter, in a suitable organic solvent. Of course, this area is again a lot of proprietary know-how, since you have to adjust the molecular weight range by adjusting the temperature, concentration, and radical scavenger. Making the polymer in the form of a block copolymer is also useful, but not described in this patent (but any polymer scientist can think of this). Some of the polymer methods don't even require a pH adjustment. (That is, if your kettle pH is 5.5 or 6.5 or something in that range at the conclusion of growth stage, which is very typical, then you can just add the coagulating agent without even monitoring or adjusting the pH. This is really convenient.)

rmazzullo
04-27-2008, 01:28 PM
All well and good...I'll just whip out the ol' phone book and call my local polymer scientist. He (or she) should be listed right after plumber.

Any slight chance you can boil down the 'information' you provide into practical, usable procedures? You must have acquired extensive results from your work in this area. You couldn't have thrown them all away.

Or, how about listing just the patent numbers and a link to the document, as was originally intended at the beginning of the thread?

Bob M.

Ryuji
04-27-2008, 01:49 PM
http://www.google.com/patents?id=EpooAAAAEBAJ&dq=5132203


The laminar structure tabular grain is not very easy to make and the sensitivity enhancement is not as great as the radial stracture (which is the subject of a series of patents by Fuji Photo Film people), and also has the disadvantage that the grains can become too thick to be useful. Indeed, this invention was superseded by Kodak's own people, e.g., US Pat 5518872.

The main signficance of this patent is its claim 11 and examples 2, 4, 6 and 7. However, use of hexacyano complex dopants are phased out by Eastman Kodak, Fujifilm and Agfa, at least, due to toxicity of waste water. For alternative technologies, see US Pat 6732419 B1.

Ryuji
04-27-2008, 01:56 PM
Oh I might also add. Laminar structure was effectively used by Konica to make high speed color films that have reduced sensitivity to cosmic rays and gamma radiation. They actually did it the opposite to the Kodak patent mentioned above, and they made the iodide-rich layer on the surface. One important and very curious key issue in this is how they managed to get this emulsion developed in the standard C41 processing, as this type of emulsion takes long time to develop.

Kirk Keyes
04-27-2008, 06:52 PM
Ryuji -

Thanks for the patents. But remember, keep comments short and sweet. State what you find useful/interesting in the patent, and then move on to the next.

If you want to give additional comments, start another thread, state your comments/finding and then please put a link back into this thread to make it easy to find the comments in the future.

Neanderman
04-27-2008, 08:40 PM
Any ideas on how to print these out? It's a quicktime video or something...

The USPTO website uses a free plug-in called 'AlternaTiff' to display the images. These can then be printed or saved to disk (as a regular TIFF file). The saved TIFF files can then be converted to PDF with Acrobat.

Ed

Neanderman
04-27-2008, 08:51 PM
So does anyone have a good patent to look at for sulfur + gold sensitization?

Here is one:

http://www.google.com/patents?id=JS9iAAAAEBAJ&dq=2399083

Waller (Ilford), 2,399,083 - Photographic materials