High Precision Hand Coating Blades

[Donald Miller]

I agree with what others have said...this is too important to just give up on.

 

[David A. Goldfarb]

Just to give an example of the large sheet issue for those who aren't aware of it (and I'm sure PE is aware)--at the albumen workshop I recently attended we looked at a an early 20x24" albumen proof that Daniel Levin had made with one of John Dugdale's negatives, just as he was learning to work with the large sheets. With albumen, the interface between the albumen coating and the sensitizing solution is critical, making brushing impossible, because there will be a streak at each edge of the brush, and floating becomes increasingly tricky as size goes up, because you'll get marks if there is any jerkiness in floating the albumenized sheet on the silver nitrate solution. While we kind of liked the handmade artifacts on the proof, Daniel assured us that gallerists are not generally of the same opinion, and that a print with concentric marks from jerky coating would be unsaleable (unless the artifacts were part of some clear aesthetic plan).

One can learn to float a 20x24" sheet evenly the traditional way (larger actually, since the edges would be cut off), but practicing with that big tray of silver nitrate solution can get very expensive.

 

[Photo Engineer]

Well, I'm in Rochester NY. The center of the film universe in the USA.

I would try to get to the APUG conference in Toronto, but the ICPS conference (International Congress of Photographic Science) is in Rochester the same week IIRC, and I want to attend that. It is high on my priority list as well.

However, anyone on their way to Toronto going past Rochester (or across the lake on the Rochester <-> Toronto ferry) is welcome to stop for a demo, if I cannot make it to the APUG event. Well, you can stop even if I do make it to the APUG event.

I'm not going to give up. I'm going to wait until they stop making film and you are all cornered and then I will have you all in my hands. Muahahahaha.

Just kidding.

PE

 

[Photo Engineer]

David, unfortunately as with everything there is also a learning curve here and the larger the size the harder to coat uniformly. I must add that using the blade is easier and takes less solution to coat a given area, but you are still subject to motion variables if you are inexpert at using the blade. This introduces horizontal chatter marks as the blade varies in speed across a large sheet.

The nice thing is that you can practice with nothing more than a large sheet of inexpensive paper and some dyes in water and gelatin and keep at it in the light until you get your technique down perfect. This is what I did.

Another nice thing is that with this method, you can coat multiple layers and keep them isolated from each other. I have coated color materials this way with up to 6 layers. So, I'm even preparing for that eventuality. The need to hand coat color. I truly hope it never comes to that.

PE

 

[removed account4]

hi PE:

i too have an interest in this sort of thing.

i was wondering ...besides a blade being a constant distance above the surface being coated, does this sort of device work the same way one would use a glass rod for spreading emulsion type substances ... like a cross between a squeegee ( windshield wiper blade ) and a razor blade --- with a constant gap/height ( = more percision)?

can't wait to see the pix!

much thanks -
john

 

[mikewhi]

This sounds interesting from a technical, artistic and Dr. Strangelove aspect (which was filmed in B&W, BTW). I can just see PE down in a bomb shelter, surrounded with paper, chemicals and 200lbs of SPAM and crackers coating away.

Seriously, I don't forsee the demise of B&W films and papers any time soon. I believe MAS will create a replacement for AZO. I believe Eastern Europe, England, China and other 3rd world countries will supply film and paper for much of the remainder of my life. If the paper gets crappy, we can easily coat pt\pd.

That all said, I find this interesting enough to be willing to participate. I'm not sure I can fly to Rochester for a workshop (or any reason, for that matter) but the materials and instructions should be a no-brainer. PE, could you make a simple, non-professional video of you coating (using dyes) so we can see how it is done? Sell it all as a kit - video, coating blade, formulas, and starter amounts of paper and chemicals for a set price. That business you could run out of your basement\bomb shelter rather easily.

Lynn Radeka does something similar with contrast masking - he sells instructions and materials directly and workshops are optional.

Please don't give up on this. I don't want to sound morbid, but there aren't many of you around, and you're not going to live forever, especially in those Rochester winters. You have a type of expertise that will soon be absent in this world. Please pass the knowledge along. I'm no chemist\rocket scientist but if you distill your knowledge down into a teachable process, we can learn it.

Remember, the guy that discovered gun powder didn't keep it to himself - he passed it down to the younger generations and see how well that knowledge has served us to this day!

-Mike

 

[jimgalli]

I'll go on record with the folks expressing interest. Will the 8" blade also work for 8X20 sheets? Wondering if a single blade would be practical for several applications like using an 8" blade to coat 7X5" 7X11" 7X17" 8X10" and 8X20".

 

[Dave Wooten]

That makes 2 in Nevada that are interested.

 

[Photo Engineer]

This sounds interesting from a technical, artistic and Dr. Strangelove aspect (which was filmed in B&W, BTW). I can just see PE down in a bomb shelter, surrounded with paper, chemicals and 200lbs of SPAM and crackers coating away.

Seriously, I don't forsee the demise of B&W films and papers any time soon. I believe MAS will create a replacement for AZO. I believe Eastern Europe, England, China and other 3rd world countries will supply film and paper for much of the remainder of my life. If the paper gets crappy, we can easily coat pt\pd.

That all said, I find this interesting enough to be willing to participate. I'm not sure I can fly to Rochester for a workshop (or any reason, for that matter) but the materials and instructions should be a no-brainer. PE, could you make a simple, non-professional video of you coating (using dyes) so we can see how it is done? Sell it all as a kit - video, coating blade, formulas, and starter amounts of paper and chemicals for a set price. That business you could run out of your basement\bomb shelter rather easily.

Please don't give up on this. I don't want to sound morbid, but there aren't many of you around, and you're not going to live forever, especially in those Rochester winters. You have a type of expertise that will soon be absent in this world. Please pass the knowledge along. I'm no chemist\rocket scientist but if you distill your knowledge down into a teachable process, we can learn it.

Remember, the guy that discovered gun powder didn't keep it to himself - he passed it down to the younger generations and see how well that knowledge has served us to this day!

-Mike

Mike, I am scared now being equated with the guy who invented gunpowder, and Dr Strangelove. Ahahahaha. Me in my white lab coat. My wife makes me wear one now after destroying too many good clothes. But then I found that RA blix removed the stains from my t-shirts and pants.

I don't own a d*****l video camera. But, what you say has merit. Maybe I should go buy one of those faulty Sony cameras and make a tape.

Actually, anyone have any thoughts on a workshop at the Formulary? I can talk to Bud about that as well as seeing if there is a way to distribute the information and 'kit' that way. Any other ideas?

You are right. The retirees newsletter list those going to the big darkroom in the sky twice a year. That list makes me feel so sad over what is being lost to all of us. And the same is true of engineers from Agfa, Fuji and etc.

PE

I'll go on record with the folks expressing interest. Will the 8" blade also work for 8X20 sheets? Wondering if a single blade would be practical for several applications like using an 8" blade to coat 7X5" 7X11" 7X17" 8X10" and 8X20".

Jim, the width is controlled by the width of the blade. They are 1/4" oversize to leave a selvedge to trim off for uniformity. Length of the coating is determined by the length of the paper or film. It is even possible to use a pump and roll method and use these blades to coat a continuous roll. Practically, you are able to coat about 16 - 20 inches in length due to the average reach of a person.

The blades contain a 1/2 inch square inner well for fluid. That is more than enough for most applications, but there is no reason why they cannot be 2x2 or 3x3 except weight goes up.

PE

 

[Photo Engineer]

hi PE:

i too have an interest in this sort of thing.

i was wondering ...besides a blade being a constant distance above the surface being coated, does this sort of device work the same way one would use a glass rod for spreading emulsion type substances ... like a cross between a squeegee ( windshield wiper blade ) and a razor blade --- with a constant gap/height ( = more percision)?

can't wait to see the pix!

much thanks -
john

This device has a constant (adjustable) gap and works like a squeegee with a well for containing the fluid and a leading edge to smooth out the paper surface and make sure it is flat for coating.

It is basically very simple.

PE

 

[magic823]

Actually, anyone have any thoughts on a workshop at the Formulary? I can talk to Bud about that as well as seeing if there is a way to distribute the information and 'kit' that way. Any other ideas?


PE

You have a workshop at the Formulary, I'll be there!

Steve

 

[Photo Engineer]

Hi Ron.

Yes, I'm interested in the blades, the emulsions, and the workshop (and the new/improved fix formula you hinted at). Shine on you crazy diamond.

Jay

I'll keep on working Jay.

Right now, tests with the SF VII show greatly reduced wash times will give archival levels of hypo. I have high hopes for it, but I won't have proof until I subject some prints to keeping tests. What good is a chemical test against the actual keeping. Even accelerated keeping is better than the chemical 'proof'. I learned that the hard way.

I probably have a good C41 and E6 blix too. ~finally~

Have a few proofs there to work out too.

Working on some new developers as well. Very high capacity, good quality film and print developers.

Something to keep me busy nights in these Rochester winters. I don't want to go out and freeze to death.

PE

 

[Kerik]

However, anyone on their way to Toronto going past Rochester (or across the lake on the Rochester <-> Toronto ferry) is welcome to stop for a demo, if I cannot make it to the APUG event. Well, you can stop even if I do make it to the APUG event.

I'm going to be in Rochester the week of Nov. 7. Perhaps I could stop in and see what you're up to?

 

[David A. Goldfarb]

As far as video goes to demonstrating the technique of using the blade, it would probably be short enough to put on the web. For examples, check out the videos at http://albumen.stanford.edu

 

[Photo Engineer]

I'm going to be in Rochester the week of Nov. 7. Perhaps I could stop in and see what you're up to?

Yes.

Provided you can get into and out of Rochester through the snow...

Please contact me via e-mail or private message here on APUG.

PE

 

[Kimberly Anderson]

I'm going to break my answer into two responses.

First off, your initial post asked us if we were interested in something that most if not all of the people here had no idea what you were talking about. You mention later on in your thread, in your lengthy response, that the blades you were asking about were something that you had fabricated and designed yourself. Now, don't take this personally, well..OK, take it personally if you want, that's fine with me. How in the heck are we supposed to have an opinion of something that we've never heard about? I was thinking to myself as I was reading your long response that THIS was what I wished you would have written in your FIRST post. I have a much clearer understanding now of what you're trying to do and how it can apply to me and what I want to do photographically.

Second off, YES YES YES, this is something that sounds very very exciting!
My enthusiasm increased exponentially when I understood what you were talking about and how I can use it with my own work.

I apologize for not asking for more details about your blades at the start of the post. Now that you've given us some details it sounds like something that most if not all alt. photographers could potentially use.

Myself, I'm getting ready to do some large Kallitypes, pt/pd prints, etc., and the blades would be a nice way to potentially make very nice even consistant coatings.

I could attend a workshop in Montana also. Makes sense to have it affiliated with all things Alt.photo. There or maybe at an APIS conference in Santa Fe. Either I could attend.

The last time I was in Rochester I was looking at attending RIT as a grad. student. I realized that most if not all of what you guys did there was way over my head.

Let us know how this progresses and how we can participate. There is nothing as exciting as the spirit of innovation (well, maybe a few things...).

 

[Photo Engineer]

Michael, all good comments.

My initial error was assuming that people who coat their own or want to, knew what a coating blade was. They are as old as the 30s or 40s or thereabouts, and are used in a number of coating industries. I used them all the time at Kodak when I had small samples. I was puzzled that you could not get them easily and that people would spend nearly $100 for a paintbrush to coat silver gelatin when a blade would do so much better.

When I got started in this, I was surprised at their expense ($1200 for an inexpensive one - and this should have clued me in on why they were not better known) and when I started this thread I learned that there was a lack of knowledge of them in general among the people represented here. It is more a matter of culture than anything else and assumptions.

Well, the ones I have here are going to cost about 2x - 3x as much as a very high end brush but a lot less than what I found out there. However, quality will be better and they will last a lifetime.

I'm getting an education out of this thread, believe me. Comments like yours clarify my thinking. Thanks.

I am presently writing up this work and putting together the foundation for a kit of chemicals and equipment needed to do this type of work. Specific formulas will be included for 3 grades of contact paper, 3 grades of enlarging paper (that will be part of tonights work), and an orthochromatic film (I have one but it is too slow). I have stated elsewhere that I'm trying to get a reliable source of Baryta paper, but I have two other suitable paper supports in-hand that work well.

I'm headed for the darkroom now to begin coating for the evening. I've got to get higher contrast for the enlarging paper. Wish me luck. I'll know by about 1 AM Eastern Time.

PE

 

[Jim Chinn]

I would also be interested in a workshop at PhotoFormulary if the opportunity presents itself.

 

[Photo Engineer]

Ok guys, I sent a tentative inquiry to Bud at the Formulary. This may be possible but will depend on the schedule there and mine. The workshop schedule is filled with excellent people. Squeezing a new one in may be difficult and I will not feel bad if this does not fit in with them. I took the Weber Vestal workshop there in '04 and the whole setup is superb. I can heartily endorse their work. Maybe I can live up to their high standards. If I do a workshop, that is for you to judge.

There are other irons in the fire too, so lets wait and see.

Jay, I have a grade 0.5 and about 1.5 when I wanted 1, 2 and 3. Some additives didn't pan out at all. So, I'm still working on the enlarging speed paper. It is also 2 - 3 stops slow of what I want but still usable on-easel. Average exposure is 12" at f8 - f11 as opposed to my usual f22 for the same negative.

Humidity must be down a bit. The coatings were dry about 1 hour earlier than expected.

Thanks for all of the nice comments and off-line communication. It is appreciated. It is hard to work in the dark (umm literally and figuratively) and not know if anyone is really interested.

PE

 

[Photo Engineer]

I think they'd be worth their weight in gold for making carbon tissue, which can be done in roomlight.

Jay

Jay, Sandy, anyone in carbon, I offer to make a carbon coating to try this out. I have some ideas about reducing bubbles and defects. I've been giving a lot of thought to carbon.

I need a suggested starting point for a formula (your favorite) and a suggested support.

I don't want 'your secret formula' a good generic starting point for g/dm sq and content would work. Since I don't do carbon, it would take some time for me to get the ingredients, but from there, I can crank out a good bit of the stuff rather quickly.

PE

 

[magic823]

My carbon formula is at home, but I'll send it to you.

 

[sanking]

Jay, Sandy, anyone in carbon, I offer to make a carbon coating to try this out. I have some ideas about reducing bubbles and defects. I've been giving a lot of thought to carbon.

I need a suggested starting point for a formula (your favorite) and a suggested support.

I don't want 'your secret formula' a good generic starting point for g/dm sq and content would work. Since I don't do carbon, it would take some time for me to get the ingredients, but from there, I can crank out a good bit of the stuff rather quickly.

PE

I will be happy to send you a carbon formula, and/or a small bottle of pigmented gelatin ready for coating if you like. If I add some thymol the pigmented gelatin solution will last long enough for shipping of three to four days, and you can then freeze it untl you are ready to use it.

Let me remark that I saw a coating machine that I assume to be of our design at the Formulary this summer and thought about how it might be used for making carbon tissue. First, you would need to adjust the spacing so as to give a wet coat height of somewhere between, 0.5 mm to 1.0mm. Second, you would also need to find a way to keep the blade very warm as it passes over the tissue. The pigmented gelatin cools down very quickly and you need a warm blade to heat it up again, which will also dissipate the bubbles.

In my tissue making I often use a method that is similar in concept to the blade to establish a particular coating height. What I do is cut a rectangle in a piece of magnetic sign material and use this over a peice of galvanized sheet metal. To coat I first put the paper or plastic support on the sheet metal and wipe away any excess water. The magnetic rectangle is then placed over the paper. I then pour the pigmented gelatin solution on the paper and push the rod (which is heated to about 120F) over the solution. The rod is supported at the two sides by the thickness of the magnetic sign material, and this in essence defines the height of the coating. I am including a .jpeg image which may clarify the procedure.

In most cases, however, I find it more expedient to just pour the warm pigmented gelatin on the paper and just spread it by hand to the edgdes of the magnetic sign material. If the work area is level gravity will cause the coating height to be virtually the same over the entire area of the tissue. The key to this operation is to have the pigmented gelatin at a temperature that will allow enough time to spread it evenly over the support. This would also apply to the use of a coating machine.

Sandy

 

[Photo Engineer]

Sandy, I would be happy to oblige you.

My design is nothing like what you saw at the Formulary. It will adjust to the gap width you specify. I stabilize my gelatin with thymol as well and can coat just fine with it present.

Please send me a note off-line and we can set something up.

Magic, glad to oblige you as well. Just message me off-lne.

PE

 

[scootermm]

Im gonna continue to show my ignorance (although likely Im not the only one wondering) but the blade is kept at a certain height... this be of very high precision from what youve been saying PE. but what Im wondering about how this precision will carry over into the paper. Id imagine even with the most highly crafted paper it still would have discrepancies in width, not to mention its "flatness". Humidity, all that stuff seems to have a direct and sometimes even noticeable effect on the flatness of the actual sheet.
would a vacuum frame of sorts be need to keep the paper entirely flat or would the coating need to be done along a roller to maintain a constant distance (like the Doctor blades use)?

 

[Photo Engineer]

Scooter, since the blade rides on the paper, if the paper varies in thickness the blade moves up and down and the end cap blade rides with it keeping a constant distance from the paper. We used to run edge to edge, end to end silver analyses on our hand coatings at Kodak and the uniformity was quite good.

You are right though in that your coating is only as good as your paper and craters or hills are not going to behave correctly but variations in the thickness of the paper will generally not cause a serious problem.

A vacuum frame works for film support and for RC support, but will not work for FB paper. This is due to the fact that FB paper expands when wet and should be free to do so otherwise it will kink and bend between vacuum channels causing 'artificial' hills and valleys in your paper and this will lead to non-uniformity.

So, the best surface for FB is just a cool slab of marble, granite, or stainless steel. Tape the paper down and let the heated blade do the rest. The coating goes down smoothly and the cooler paper surface aids in letting the gel layer flow just enough to develop a uniform layer in the thickness you want and then set up.

But, to be fair, we are working on a vacuum hold down system for film and RC, along with chill set and heat rise capability. Its just that this will be a rather expensive piece of equipment and attractive only to the rich and famous. This unit would be designed to take sheets of paper and film up to about 16x20. Our goal is to make something that is relatively inexpensive and that gives good enough uniformity. So far, it does meet those criteria (depending on what you feel is a reasonable cost and good enough uniformity). Everyone who has seen the prints (not scans - I'm talking originals) has been impressed so far.

PE