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Re: Ambient temperature and playing records
Posted: Wed Aug 30, 2017 4:18 pm
by HisMastersVoice
bfinan11 wrote:Does anyone know what color these formulas would have been without the dyes? Assuming it wasn't black, when did black become the standard, and why?
I'm guessing a relatively unappealing brown color....
Re: Ambient temperature and playing records
Posted: Wed Aug 30, 2017 4:51 pm
by donniej
bfinan11 wrote:Does anyone know what color these formulas would have been without the dyes? Assuming it wasn't black, when did black become the standard, and why?
The filler material was clay from the South (I forget where) and Pennsylvania. It was mostly bentonite, which is the clay used in most kitty litter. This is a similar color to Perfect, Vocalion and the other orange/brown discs of the era. This is the natural color of the material. From what I've read, 2% carbon was added to make the discs black.
Why? Probably because the coloant was cheap and it had a nice shine.
Re: Ambient temperature and playing records
Posted: Wed Aug 30, 2017 5:46 pm
by Orchorsol
Many other fillers appear to have been used in various formulations, including other clays (e.g. china clay), calcium carbonate (whiting, rottenstone etc) and even ground slate by some manufacturers! Also sometimes other materials that whilst increasing strength must have contributed to noise - like floc and cotton waste. Carbon black, as well as acting as a pigment, is also a powerful structural filler, even in relatively small quantities.