'Signature', 'watermark' => 'Watermark', 'engraving' => 'Engraving', 'scratch' => 'Scratching', 'stamp' => 'Stamped', 'overprint' => 'Overprint', 'embossing' => 'Embossing', 'handwritten' => 'Handwritten', 'glued' => 'Glued', 'embroidered' => 'Embroidered', 'sewn' => 'Sewn', 'screwed' => 'Screwed', 'burnt_in' => 'Burnt in', 'riveted' => 'Riveted', 'nailed' => 'Nailed', 'hallmarked' => 'Hallmarked', 'punched' => 'Punched', 'scarified' => 'Scarified', 'cast' => 'Cast', 'painted' => 'Painted', 'drawn' => 'Drawn', );