Color is very important to the study of the Loetz decors.  In general, when referring to a particular décor, the ground (the type and color of the glass onto which the decoration is applied) is mentioned first and then the décor name. i.e. cobalt Papillon, Crete Norma, etc.  A different ground color from what is specified for a particular décor can either completely change the name of a décor (i.e. Argus vs. PG 3/430 or Ausf 113 vs. Ausf 139) or require that the example be placed in a décor variant category if it is not specified for that decor. 

The descriptions of glass colors used by Loetz are listed below in English with the German word for each color provided in parenthesis.  This list is taken from ‘Loetz Bohemian Glass 1880-1940’ Mergl et al, Hatje Cantz / Neue Galerie, 2003. More details about this important Loetz resource and other key literature can be found by clicking ‘Publications’. Where possible we have provided links to various color examples that can be found on the site.

Blues:aqua/sea-blue (Aqua, Seeblau); aquamarine (Aquamarin); blue enamel (Blau Email); celestial/pale blue (Coelestin, Hellblau); cobalt (Cobalt); dark blue (Dunkelblau); heliotrope (Heliotrop); luminous blue (Lichtblauopal);blue opal; mountain-blue (Bergblau); ozone (Ozon); royal blue (Königsblau); sapphire (Saphir); sky-blue (Himmelblau); turquoise (Türkis)
Browns:bronze (Bronce); brown (Braun); chestnut (Maron); Havana brown (Havanna Braun); volcano (Vulcan)
Coloreless / White:cloudy white (Weiss Getrübt); alabaster-white (Weissalabaster); Arcadia (Arcadia); brilliant opal (Brillantopal); Candia (Candia); crystal (Kristall); ivory (Elfenbein); white enamel (Weissemail); white opal (Weissopal)

Grays:pearl-gray (Perlgrau); silvery gray (Silbergrau); steel-gray (Stahlgrau)
Greens:celadon (Seladongrün); Crete (Creta); dark green (Dunkelgrün); Diana (Diana); golden green (Goldgrün); grass-green (Grasgrün); greenish-bronze (Broncegrün); imperial green (Kaisergrün); jade-green (Jadegrün); leaf-green (Blattgrün); May-green (Maigrün); moss-green (Moosgrün); mother-of-pearl-green (Perlmuttergrün); olive-green (Olive); Olympia (Olympia); pea-green (Erbsgrün); Reseda (Resedagrün); Russian green (Russischgrün); seed-green (Saatgrün); stone-green (Steingrün); Urania (Urania); yellowish green (Gelbgrün); zephyr (Zephir)
Oranges:mandarin (Mandarin); orange (Orange), Orange opal
Reds:aurora/pink opal (Aurora/Rosaopal); camellia-red (Camelienrot); coral-red (Korallrot); fire-red (Feuerrot); garnet (Granat); hyacinth (Hyacinth); imperial red (Kaiserrot); light coral-red (Corallin); Makart/reddish-aurora (Makart/Aurora rötlich); metallic red (Metallrot); pale pink (Zartrosa); pink (Rosa); rose-colored (Rosalin); ruby (Rubin); salmon-pink (Lachsrosa), Deep-red (Tiefrot)
Violets:amethyst (Amethyst); metallic violet (Metallviolett); opal-violet (Opalviolett); pansy (Pensée); smoky (Rauchamethyst); violet (Violett)
Yellows:Annagelb/greenish yellow (Annagelb); brilliant yellow (Brillantgelb); golden amber (Goldamber); lemon-yellow (Citrongelb); opaline (Opalin); luminous lemon (Lichtcitrongelb); metallic yellow (Metallgelb); new red (Neurot); silver-yellow (Silbergelb); Thea (Thea); topaz-yellow (Topasgelb)