One of the most important aspects of kitchen and bath design or renovation projects is lighting. All of the other elements of a great kitchen or bath - cabinetry, plumbing fixtures, countertops, tile, paint or wallpaper - will not live up to their potential without good lighting. Kitchen tasks are much easier with good lighting, and bathroom lighting is especially important at the vanity/mirror area. Consideration for optimal lighting at different times of day is important as well.
Layered lighting for either kitchen or bath is an optimal solution. General, or ambient lighting can be provided by recessed and/or surface-mounted ceiling fixtures. It's important to avoid shadows at main task areas in the kitchen, so the placement of recessed lighting in relation to cabinets, countertops, and islands is crucial. General lighting is enhanced with task lighting for key areas.
For example, at the kitchen sink or at island/bar areas, pendant lighting or rail lighting can add just the right amount of additional illumination. The many varied options available for pendant or rail lighting present a wonderful opportunity to add interest or fun to the overall decor.
Undercabinet lighting is very useful for food prep, clean-up and other tasks at countertop areas, and can be virtually invisible in LED, line voltage or low voltage options.
To avoid shadows and dark zones in the bathroom, vanity lighting or wall sconces in addition to basic ceiling lighting are important, and offer great design options. The selections for vanity lights and wall sconces are almost endless, from simple, super low budget options to high end choices with wonderful metal and glass finishes. The coordination of plumbing fixtures, light fixtures and cabinet hardware will take the bath design to a professional, finished look.
One of the most useful articles I've read on
bathrooom lighting is from "This Old House" and I refer to it occasionally when working on bath design projects since it addresses not only types of vanity and shower/bath lighting, but bulb types, dimmers, and safety as well. It's a great summary of the key aspects of lighting.