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: Healing Potions
RecipeMakesReagentsNeedsSkill-up
Minor Healing Potion
Minor Healing PotionYellow 55Grey 95
Lesser Healing Potion
Lesser Healing PotionYellow 85Grey 125
Healing Potion
Healing PotionYellow 135Grey 175
Greater Healing PotionTaught by Manual: Greater Healing Potion, requires 155
Greater Healing PotionYellow 175Grey 215
Superior Healing PotionTaught by Manual: Superior Healing Potion, requires 215
Superior Healing PotionYellow 230Grey 270
Major Healing PotionTaught by Manual: Major Healing Potion, requires 275
Major Healing PotionYellow 290Grey 330

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