Each recipe is orange until its yellow rank and grey from its grey rank. When the ranks differ, it turns green somewhere between the two; the client files give both ranks but not that point. Equal ranks go straight to grey.

First Aid: Camping
RecipeMakesReagentsNeedsSkill-up
First Aid Kit
First Aid KitYellow 20Grey 25
Toxin StudyTaught by Blueprint: Toxin Study, requires 140
Toxin StudyYellow 140Grey 145
Plague Doctor's LaboratoryTaught by Blueprint: Plague Doctor's Laboratory, requires 300
Plague Doctor's LaboratoryGrey 300

From the Forever beta client files, build 1.60.1.70630: the SkillLine, SkillLineAbility, TradeSkillCategory, SpellReagents, SpellEffect, SpellTotems, SpellCastingRequirements and ItemEffect tables.