Very good exemple of a white that's quite more complex than just a "Greyish" off white. On this piece from the famous french ceramist Capron the orange that covers the inside of this vase is also a "multi layers" color which means that it needs one or two undercoats of different color to look exactly like the original glaze.
Step 1: Assessed damage and repair on a Roger Capron
ceramic vase:  received several broken pieces near top
portion of vase;  two pieces were missing. 

 Step 2: Reassembled pieces with invisible glue.

Step 3: Cracks filled with fast hardening cream then sanded until original shape achieved.

Step 4: Pre-layer of black paint applied first.
Step 5: White layer added next in order
to attain a final color of off- white

 
Step 6: Inside of vase is painted with a matching
orange color. Finally, a strong enamel is applied
for a perfect finish.