Methyl Cellulose

The reagents used in all of the Old Pol and Fuji instant films have a thickening agent in them to help control the spread of the reagent as it bursts from its pod and is then rolled between negative and positive.

Methyl Cellulose is the material, and here is a convenient, readymixed source, though we have bags of powder that can be mixed up to make many gallons of the same material.  It is amazing how little methyl cellulose powder is needed in water to make a gel. Another interesting property is the mixing of the methyl cellulose, which occurs readily in cold water, but very poorly in hot water.


I've been concocting reagents using powdered methyl cellulose as seen here.  But there are times when a ready to go gel is handy for spread rate experiments.

Viscosity of the gel in the image you see above is similar to that found in pods, but perhaps a little more jelly like.  The reagent mustn't run, nor should it fail to flow.  It is tempting to simply mix reagent III into some of the jelly, but it would be too thin and runny that way. Still, if you need to experiment with flow, this is far more convenient, and probably much more consistent.