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Go Back   APUG > APUG English Forums > Darkroom > Silver Gelatin Based Emulsion Making & Coating > Film coating machine (homemade) on Flickr

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Old 12-25-2007, 05:34 PM   #31 (permalink)
AgX
 
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I still don't understand the idea of slicing the base/film into a loop.

You save on additional base for threading (for which you could use special leader tape to be reused if economical advantageous). But at the same your coating is limited to a fixed length (less than 14m due to loss until the coating runs stable).

Or am I again slow on the uptake?
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Old 12-25-2007, 05:56 PM   #32 (permalink)
 
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Quote:
Originally Posted by Photo Engineer View Post
Excellent work.

I might mention that this is a small scale version of a 12" coater at Kodak that was called P3. It resembles it even to the arched chill cabinet.

PE
PE,
Is it possible to obtain some photographs of the P3? Any manuals etc for the the P3 would also be of great interest! It seems that Kodak factories around the world are being destroyed at a rapid pace and all this information will be destroyed with them. (I have heard of Kodak plants in Australia, Canada and the US that are now demolished).

Is there a Kodak PR or Archives manager that might be helpful in preserving this technology?

Emulsion.
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Old 12-25-2007, 07:25 PM   #33 (permalink)
 
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Quote:
Originally Posted by ben-s View Post
PE;
I noticed something on this photo:
http://www.flickr.com/photo_zoom.gne...6919391&size=o
When I saw it, I wondered whether the perspex box under the front of the head and roller was for vacuum. There seems to be a hose running to it...
Ben;

That is the correct design for the vacuum attachment, but I didn't see any hose running to it, nor did I see any catch basin for underflow (or overflow, whatever....) as you tune the flow/vacuum combination. So I discounted it as being an in-use vacuum system. IDK.

PE
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Old 12-25-2007, 07:27 PM   #34 (permalink)
 
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Quote:
Originally Posted by AgX View Post
I still don't understand the idea of slicing the base/film into a loop.

You save on additional base for threading (for which you could use special leader tape to be reused if economical advantageous). But at the same your coating is limited to a fixed length (less than 14m due to loss until the coating runs stable).

Or am I again slow on the uptake?
This same loop method was used by Agfa in their experimental Geissmachin for research in which a continouous loop was used for making short lengths of coating with several layers.

PE
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Old 12-25-2007, 07:30 PM   #35 (permalink)
 
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Quote:
Originally Posted by Emulsion View Post
PE,
Is it possible to obtain some photographs of the P3? Any manuals etc for the the P3 would also be of great interest! It seems that Kodak factories around the world are being destroyed at a rapid pace and all this information will be destroyed with them. (I have heard of Kodak plants in Australia, Canada and the US that are now demolished).

Is there a Kodak PR or Archives manager that might be helpful in preserving this technology?

Emulsion.
AAMOF, the P3 machine looked (<- note past tense) much like what we see depicted here, but it was wider and had a front end bombardment setup for electrostatic bombardment of film and paper. It also had a takeup roller instead of a continuous loop.

There were other differences such as it having a different drying (hot) cabinet, but I'm not sure of the details now.

I only used this for prebombardment of support and my friends only used it for making single layer coatings for tests, so it is quite hazy in my mind. The only thing that stands out is the arched chill cabinet which was a design feature of the P3.

George Eastman House and RIT both have coating machines that are currently not on display but rather in storage.

PE
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Old 12-26-2007, 02:32 AM   #36 (permalink)
 
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Quote:
I still don't understand the idea of slicing the base/film into a loop.
I assume it is because this is not a volume production operation, but an experimental coating machine. Having it in a loop allows for easy recoating for multiple layers, and 14m is more than enough to test the emulsion.

I'll confirm that however.
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Old 12-26-2007, 09:40 AM   #37 (permalink)
 
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When coating film, it is not a good practice to roll it up before you put on an overcoat. The process of rolling it up can introduce scuffs and other abrasions including small fog spots where the emulsion is rubbed. This machine avoids that problem by having a continuous piece of film that can be doublecoated in one operation.

PE
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Old 12-26-2007, 09:54 AM   #38 (permalink)
 
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PE,

What components are in an overcoat? How is this different than adding hardeners, etc to the emulsion / coating formula itself?

Is an overcoat a customary (or preferred) step in film / paper making, even on a small scale?

Thanks,

Bob M.
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Old 12-26-2007, 10:02 AM   #39 (permalink)
 
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Bob;

An overcoat is only needed if the film is rolled up on a takeup spool.

It can consist of anything you want to add such as antifoggants, hardeners, matting agents, antistatic agents, tints, dyes.... Well, you get the picture.

Generally, I coated an overcoat even at a small scale, but if we didn't mind the scuff marks and blemishes we just made one pass. Typically, Kodak machines could coat 2 layers with 2 hoppers and a takeup spool. The machine was T shaped with a hopper at each end of the - bar at the top and drying between. Then the film or paper looped down to the long | bar of the T and was wound up.

This is not true of the slide hopper machines or the very tiny machines. P3 was an example of the single ended machine such as in the post above, but there was no loop. The coating was rolled up at the end of the machine.

PE

Last edited by Photo Engineer; 12-26-2007 at 12:36 PM. Reason: Removed double signature.
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Old 12-26-2007, 12:29 PM   #40 (permalink)
 
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dark orange,

Can you shed some light on how the bubble trap is supposed to work? Do you know the order in which the bubble trap / inline filter / zenith pump are connected, and if there are more than one filter and trap placed in the emulsion 'plumbing'?

Thanks,

Bob M.
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