I do not know what a hand coating blade is. Is it a blade in a jig that moves over the paper and you apply the emulsion bead? Does the blade apply the bead through holes or slot in the blade itself?
I am also interested, especially in the possibility of coating film.
"Fundamentally I think we need to rediscover a non-ironic world"
Jim, The application of the emulsion takes place by means of a slot in the blade.
Film emulsion making and coating is much harder than making paper emulsions and coating them. That is why I started out with paper. It is also harder to get good subbed film support as opposed to getting good paper support.
Maybe I should ask another question here. Is there any interest in a workshop on emulsion making and coating? If so, comments on subject matter and interest would be appreciated.
BTW, the reason I got into this is that the base of B&W products is eroding and promises to vanish much faster than you might imagine. I'm trying to do my part to 'be prepared' and to help others be prepared.
I stated elsewhere that I started with Azo paper as it was one of the most popular and first major product to 'vanish'. I have coated 3 contrast grades of Azo type emulsion on 4 different types of paper support including the original Azo type single weight baryta paper. So, I am getting somewhere in my efforts to continue the lifetime of B&W photography.
Maybe someday I'll have to turn my efforts to color. I hope not.
Besides paper, I think you might find a very large demand if a blade is able to coat glass plates that have been properly prepared. The idea of being able to possibly craft an emulsion and apply it to a small batch of plates for specific applications would be very cool.
I for one would be very interested in a possible workshop.
"Fundamentally I think we need to rediscover a non-ironic world"
Any of the blades will work on glass, but since coating glass is easier than coating film or paper support, you may be able to do without the blade unless you want precision.
This method will lay down precise amounts of both gelatin and silver. And, it can be repeated every day, year in and year out, as long as you keep your blades in calibration.
I'd be interested in the workshop and maybe even the tools.
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Well, looks like a very low level of interest in either the blades or in a workshop.
Since either will involve a lot of effort and expense, I guess I will not go ahead with this. Maybe this will change when more products begin to vanish forever.
Thanks for your responses.
Ill reiterate what a few have said in here... what exactly is a coating blade? do you have anything that could show what you are meaning? like a jpg etc?
Originally Posted by Photo Engineer
Im still confused as to what you mean by a coating blade.
also, what are we talking for PRICE? and what kind of environment is needed to produce the product?
I'll try to explain until I get a good jpg, ok? I hate using d*****l.
Originally Posted by scootermm
You can paint light senstive material onto paper or film with a brush, but it leaves strokes and marks. You can pour light sensitive material onto plates and let it roll around and smooth out into a layer, but how thick and how uniform is it? Well, that is up to the skill of the operator. You can dip paper or film into a tray of chemicals and put down senstive emulsion. Again, how uniform and how much.
A coating blade is a precision instrument that places an exact amount of sensitized material in a precise location. This thickness is determined by a gap that is adjusted with feeler gauges and set screws. I use 5 mils. This places about 12 ml of solution on every square decimeter of support, and the coating is uniform at 5 mils. I have coated from 2 mils to 10 mils with these devices.
I can coat 4x5, 5x7 and 8x10 sheets of paper and film with a 1/4" selvedge that can be cut off. I am trying to get an 11x14 inch blade.
The intent is to have available a method for coating sheets of contact and enlarging papers and sheet film or MF film strips if or when the B&W materials become unavailable. I'm looking ahead to that day and see no technology out there for good quality hand coatings of convential materials. I am trying to supply a series of simple emulsions for this as well.
The reason I can do this is that at Kodak, we in Research had to make high quality hand coatings when using small samples. The coating machines were too big. So, I decided to re-engineer what I knew from those days and make something for myself. Along the way, I made a series of emulsions and coated them to prove the concept. The blades and the emulsions are the result of my work.
At the present time, I get near production quality matching Ilford MGIV grade 2 in 4x5 and 5x7 about 90% yield or greater. My current best paper is a contact grade Azo type work alike. I am close to an enlarging paper as well, but the contrast is a bit low for my tastes. The speed is exactly the same as the Ilford MGIV.
In 8x10, I get about 30% yield due to a design fault of my own making. I am working to fix this up.
Devices similar to these are used in the paint industry and are known as doctor blades. I would post a reference and URL, but the site seems to be off-line right now. A google search for Doctor Blades will turn up some hits.
Anyhow, the lowest price I could find was in the range of $1200 for a 4x5 blade, and that is outrageous. My design will cost far less than that and works as well or better. I am willing to find a distributor for them, and then leave it up to him after I get an initial order for them out to whoever this company may be. I don't want to sell them myself, but do want to recoup my losses / expenses in this project. But, if there is little interest, then I will simply not go to the trouble until the world beats a path to my door.
In the mean time, I am cranking out my own B&W prints on my own B&W paper.
As for price, the machine shop has not gotten back to me yet. It will probably be about $300 for a 4x5 blade, but IDK. That is a lot less than the $1200 that was the miniumum I could find currently available.
The environment is a normal darkroom. I use my darkroom with a sheet of metal for a coating surface and paper or film for the substrate to coat on. I buy Strathmore Smooth paper in 11x14 at the local art store. It works just fine.
The only extra equipment that I have is:
Stirring hotplate to reach higher temperatures for making emulsions.
Good balance for weighing out chemicals.
Pet Syringes for injecting chemicals in precise amounts in the dark.
And, all of the chemicals to make an emulsion such as silver nitrate, sodium chloride, sodium bromide, potassium iodide, and gelatin.