sulphur-yellow vs sulfur-yellow

sulphur-yellow and sulfur-yellow both are adjectives.

Word	Noun	Adjective	Verb	Adverb
sulphur-yellow	No	Yes	No	No
sulfur-yellow	No	Yes	No	No

As adjectives, sulphur-yellow and sulfur-yellow are synonyms defined as:

sulphur-yellow and sulfur-yellow: of something having the yellow color of sulfur

sulphur-yellow (adjective)	sulfur-yellow (adjective)
of something having the yellow color of sulfur	of something having the yellow color of sulfur