When you're preparing to have your passport photo taken, the colors that you wear are largely insignificant. The important part of the process is that you are facing the camera squarely, that your head is the correct size in the photo and that you meet other requirements as set by the government.
Officially, no rules about the colors you wear for your passport photo exist. The U.S. government will not reject a passport application because of your color of clothing in the photo. Some photographers request that you avoid wearing white, as it can blend in with the background and cause your head to appear as though it is floating.
The color of clothing you wear while having a passport photo taken is insignificant because very little of the clothing is visible in the photo, provided the photographer shoots it correctly. Because your head and face are the main focal points of the photo, only a slight portion of your collar is likely to be visible.
When having your passport photo taken, you are not allowed to wear a hat or other head covering unless it worn for religious beliefs, or sunglasses. If you wear prescription glasses, some photographers will request that you remove them because of the glare on the lenses. If a glare blocks or distorts your eyes in the photo, your photo will be rejected when you apply for a passport.
Valid photos must be in color and printed on photo paper measuring 2 by 2 inches. Your head must measure between 1 inch and 1 3/8 inches from the top of your head to the bottom of your chin, with your face pointed straight at the camera. If any of these regulations are not met, you will have to have the photo taken again.