Inside Analog Photo Radio - Ron Mowrey - Photo Engineer - Where Kodak Went Wrong

[PKM-25]

The major differences in films industry wide is the subbing or lack thereof for each application. Kodak makes unsubbed and subbed film supports. You can buy subbed or unsubbed supports from ICI in England for a variety of applications and IIRC, Ilford buys from ICI.

Ron, what exactly is "Subbing"? This is the first time I have heard the term used in regards to film...

 

[Photo Engineer]

Well, gelatin and water will not stick to Acetate or to Estar. So, you must make the surface of the transparent support, which is water repellant, non-repellant. To do this, you first apply a mixed water/organic mix to the support, or you bombard it with an electrostatic discharge to give it a "tooth" that is able to allow adhesion between the emulsion layer and the film. The organic/water mix is sometimes acetic acid, methanol and gelatin. This type of subbing will not work well on Estar.

If you apply a mixed water/organic mix, you are putting on a subbing layer. Then you coat your product on top. Some films are bombarded and subbed both and some films are just bombarded and coated with emulsion, so there are 3 possible coatings that can result. They are Subbed, Bombarded and Subbed, and Bombarded only. Any of these 3 can be coated on, but if the latter means is used, the Bombardment only method fades over about 24 hours.

More than you ever wanted to know I'll bet!

PE

 

[Michael W]

Is "subbing" an industry slang for "substrate"

 

[Photo Engineer]

IDK. Never ever heard of anyone using the word substrate in this context.

PE

 

[Mr Student]

Ron, thanks for giving such an interesting interview, amazing stories.

You mention your emulsion making book, where/when can this be purchased? Sorry if this has been answered before, I did search, but came up with nothing.

 

[Photo Engineer]

Try Fotoimpex in Germany, the Photographers Formulary in the US, or me. I send out limited autographed editions of the DVD, Book or DVD and book.

So, at present there are 3 sources. GEH also sells them in their store.

PE