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.

Skinning: Camping
RecipeMakesReagentsNeedsSkill-up
Camp Chair
Camp ChairYellow 20Grey 25
Field GuideTaught by Blueprint: Field Guide, requires 140
Field GuideYellow 140Grey 145
Trapper's WorkbenchTaught by Blueprint: Trapper's Workbench, requires 300
Trapper's WorkbenchGrey 300
Tanning
No readable reagent record

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