Nightingale Armor

The Nightingale Armor is set of Light Armor given to the Dragonborn and Brynjolf by Karliah before performing the initiation ritual of the Nightingales during the Trinity Restored quest for the Thieves Guild. All of the armor pieces are obtained from a box with the Nightingales symbol emblazoned on it. It is possible to pickpocket the armor back from Karliah if the player has the applicable perk.When looking closely in 3rd person mode, the Dragonborn's eyes glow white, as do other characters with the armor.

The armor container in the developers' room (accessible on PC only; the command is ) contains three sets of Nightingale Armor with varying armor ratings and enchantment strengths. The BaseIDs given are of the middle set.

Magic effects
Wearing all four pieces of Nightingale Armor grants the effect "Nightingale Armor Full Set" which increases armor rating by 25 points if the player has the Custom Fit and Matching Set perks. In Skyrim's 1.6 update the Nightingale Armor improves as you level up your light armour skill. It has a higher armour rating than some heavy armor.

Improvement
Nightingale armor can be improved using void salts. There are six levels of improvement: Fine, Superior, Exquisite, Flawless, Epic and Legendary. When combined with a high light armor skill and perks, a high smithing skill, fortify smithing potions and enchanted smithing apparel this can easily exceed 567 armor rating (which is 80% damage reduction, the maximum damage reduction from armor available).

Attributes by piece
The armor's value and enchantments are dependent on the player's level when the mission: Trinity Restored is started - not when the armor is received.

Trivia

 * Nightingale Armor is unique as it is the only type of apparel in the game to come with a cape, other than Ulfric's Clothes, Hammerfell Garb, and Vampire Royal Armor.
 * Nightingale Armor bears some resemblance to the costume worn by the DC Comics superheroes Batman and Batgirl.
 * The armor also bears some resemblance to the costume of Marvel Comics superhero Moon Knight.

Bugs

 * If the armor is worn on a Khajiit or an Argonian, the tail will clip through the cape. This applies to every suit of armor in the game.
 * Sometimes, Nightingale armor can't be upgraded even when the player has a sufficient Smithing skill, perks, and void salts.
 * Possible solution: If Fine-Cut Void Salts are in the inventory, turn them back in to Captain Wayfinder.
 * Sometimes the coloring of the Hood will go, and it will become white (as well as Nightingale hoods worn by others). Reinstalling the game seems to fix this.
 * Solution: fast travel and it should turn back to black or rewear it.
 * Solution: drop the hood on the ground during the daytime and wait until night to pick it back up and equip it.
 * Possible solution: take off the hood and put it back on repeatedly.
 * While wearing the gloves, human and wood elf fingers skin tone will always look the same no matter the character's skin tone.
 * Solution: restart the console.
 * When selecting the stone, no armor is received.
 * Argonian and Khajiit faces are shortened when wearing the hood and look like normal human head models.
 * If the player obtains all smithing perks except for the last optional one, the Nightingale armor will only upgrade to flawless. Getting the last perk seems to fix this.
 * Giving the armor to one of the armor mannequins in Proudspire Manor, then removing it, will sometimes result in a duplication of some of the pieces of the set.
 * It's possible to use mannequins in Proudspire Manor to duplicate all pieces of the set. This only seems to work with the mannequin on the right. The mannequin on the left seems to not register the hood.
 * When given to a follower who has heavy starting armor, it may not be able to get it back because it's "Your followers starting armor." The only way to get it back from the follower is to kill them and loot it back.
 * To upgrade the set past flawless, enchanted smithing items/smithing potions and 100 smithing is required. This may depend on what level the character is when the player obtain the set. (Level 20+ requires 100 smithing+enchanted items)
 * Replacing the Nightingale Hood with a Shrouded Hood still gives the set effect.
 * Can be duplicated in the Dawnstar Sanctuary after buying the master bedroom upgrade from Delvin. Place the said armor duplicated into the inventory of the mannequin then take it back again (without leaving the inventory menu). leave the area. Come back and the duplicated armor should be there (minus any improvements that have been applied it. Also works in Honeyside and Vlindrel Hall
 * Sometimes, the armor may disappear if given to a Dark Brotherhood initiate. (Needs confirmation)