A dimmer switch or three-way light bulb. Sitting with the back to the window to reduce glare. A hat with a visor for light sensitivity outdoors. Ultra violet inhibitor sunglasses for outdoor glare. The general rule is that background should contrast with foreground.
Smooth textures make colors appear lighter and uneven surfaces make colors darker.
Have her decide where and how it will be used. Reinforce the color system with large print labels or tactile shapes. Use a three-ring binder to explain in large print how each color is used. See Chapter Four for use of color in the home. See Chapter Six for color ideas to increase safe mobility.