Looks like they are too sheer and the lighting and colors outside are coming through the sheer fabric, which changes how the color of the fabric is seen from inside. This is why when you have custom drapes made, they add lining and/or interlining.

Yes, Chispa is right. It will change how the curtains look when sunlight goes through, especially for light fabric. The overall hues are harmonious and calm, I like it.

But if you want the curtains to act as the focal point, you could try beige or light brown colors, and get them lined.