Paint Store
by Kiran Kedlaya and David Savitt

answer: MAYSFIELD

This is a crossword in which each letter has been replaced by one of
nine colors everywhere it appears, and the clues to all of the answers
except the four long Across answers have been given in a random order.
The grid solves as follows:

OPEC.MCGRAW.ABE
ASEA.AREOLA.LOX
FIRSTLETTER.CRT
...KOANS...DOZE
MAO.LYE.PRAETOR
OFTHEALPHABETIN
CATER..LENA....
KRONA.JAW.TENSE
....NEON..TRIED
EACHCOLORSORTED
OILIEST.ANI.SPY
CRAM...LIARS...
EMU.ASRESISTORS
NED.WEEVIL.IRAQ
ENE.LEMONS.REEL

The four unclued Across answers together read:

FIRST LETTER OF THE ALPHABET IN EACH COLOR SORTED AS RESISTORS

Note that the nine colors represent the nine nonzero digits in the
standard color-coded labeling of resistors. (Black codes for zero;
here it is used to represent the usual black squares in the
crossword.) Using this as the ordering, the colors decode as follows:

brown: M, R, X
red: A, B, C
orange: Y, Z
yellow: S, U, W
green: F, O, T
blue: I, J, K
violet: E, G, H
gray: L, Q, V
white: D, N, P

The alphabetically first letters in each color, read in this order, spell
the answer: MAYSFIELD