some blacks are true black (Kona cottons) some are grey blacks, some blue blacks and some redish. Remember how black is made - a combination of all the colors. White are funny too - as mentioned by several above. Carry swatches of what you already have when you shop and you can compare before buying new fabric. I find a 2.5 by 5 inch rectangle of fabric stashed in a zip lock baggie is usually big enough for me to have for comparison.