tapioca starch

[titrisol]

National Starch or TIC gums have those
If you are in the US they'll even send you a small sample (200g or so) if you ask nicely

Gary,
It was Zoe Zimmerman who told me about the tapioca starch. I assume it goes in the albumen. Experiments are in order but where do you get tapioca starch?
Jack B

[hortense]

Anybody using or heard of an albumen formula using tapioca starch? I dont know how much of it goes where but the source was reliable but vanished quickly into a crowd. Tapioca starch??????
JackB

Yes, I have heard of Tapioca. I use it as as substitute to avoid my wheat allergy. Wheat starch is the "white stuff" most people call flour. But there are many types of flours. For example, wheat, corn (and corn starch), tapioca, and arrow root. It is the gluten in these flours that do the job for you guys that make your own old time (exotic?) photographic papers.

[Gerald Koch]

Tapioca, tapioca flour, and tapioca starch are all different and are not the same substance. You should be able to get tapioca starch in a health food market.

[Donald Qualls]

Actually, Hortense, it's probably the gluten that causes problems for you, if you're allergic to wheat. Starch is pretty much starch when it's really pure. However, starches derived from vegetable sources aren't usually very pure; you can get potato starch (usually sold for laundry), arrowroot and corn starch (sold for baking) and wheat starch without the gluten (usually sold as library paste or old-style wallpaper paste), even rice starch (mostly used, AFAIK, in making fireworks); I think I've even seen sago palm starch once or twice, but none are quite identical to tapioca starch because they have different impurities and adjuncts to the starch. There are also variations in chain length (starch is essentially a long-chain polymer of a simple sugar, dextrose IIRC), which govern how soluble the starch is in water and how much it hardens when cooked and dried.

Gerald is probably correct -- the tapioca pearls sold for making pudding are mostly starch, but probably have "stuff" in them that would be undesirable in a sizing for paper used in alt processes. FWIW, arrowroot starch is readily obtainable in better grocery stores (it's a hifalutin substitute for corn starch in certain baking/confectionery applications), and is the recommended sizing for some processes such as cyanotype; it'd be where I'd start if I needed tapioca starch and couldn't find it.