To get us back on topic.
In all seriousness, sometimes determining just what “color” a vestment might be can be very subjective and very difficult. Walk into a paint store and the colors are very clearly defined. Granted that textile manufacturers are just as specific, once the cloth is actually made into a vestment, it can often appear to be different “colors” depending on the lighting, and even the lining used. Words like “white” and “gold” are not very specific words afterall. White can be ivory, bone, cream, etc. etc. Most gold vestments are in-fact a shade of yellow because the only way to get a “true gold” is to use actual gold threads (possible, but rather expensive, not to mention heavy).
The only way to realy know if that particular vestment would be “yellow” or “gold” would be to go right up to it and look at it very closely. Even then, one person might describe it as gold, another might say yellow.