Scanning and converting to b/w image

Hi,

Any ideas on the best way to convert a scanned design from an old book cover to a crisp black and white image which will be used to recreate the original printing plate. Below is an example of a design scanned from an old cloth book cover. I need a b/w image i.e. all the gold in black and background completely white. I have struggled in Photoshop trying to change colours, adjust levels and thresholds etc. but cannot get it clean enough. Would I be better somehow redrawing it and, if so, how?

Please help.

I didn't find the right solution from the Internet.

References:

http://www.graphicdesignforums.co.uk/threads/scanning-and-converting-to-b-w-image.24960/

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Thanks