What Size Picture Light Do I Need?
There is an old rule for picture lights: choose one that is about half to two-thirds the width of the artwork.
It is a decent starting point.
It is not a rule I would rely on by itself.
Modern LED picture lights can throw light very differently depending on the optics, the distance from the artwork, and the height of the piece. A smaller fixture with a wide beam can sometimes light an artwork better than a larger fixture with a narrow beam.
So start with the artwork, not the fixture.
If you haven't yet decided between a hardwired and a rechargeable light, start with How to Light Artwork Without Opening the Wall.
Measure the artwork first
You need two measurements:
- overall width
- overall height
Measure the finished piece as it will hang, including the frame.
Height matters more than people expect. A light that covers a 24-inch-wide piece well may still struggle if that piece is unusually tall.
The farther the light has to reach, the more important beam shape becomes.
A good starting point for width
For traditional picture lights, a fixture around half the width of the artwork is a reasonable place to begin.
Visual Comfort still uses that as a general rule of thumb.
But I would not buy a light based on that ratio alone.
Situ Lighting makes the same point in its own sizing guidance. The older half-to-two-thirds rule came from traditional incandescent and halogen fixtures. Modern LED optics can spread light more efficiently, so fixture width does not always tell you how much artwork it can cover.
That is why I would pay more attention to the manufacturer's recommended artwork size than to the physical width of the light.
Look at the height too
Width gets most of the attention, but tall artwork is usually harder to light evenly.
A standard picture light may illuminate the top half well and leave the bottom noticeably darker.
Situ addresses this directly in its larger Vision Series by offering different optics for standard-height and taller artwork. The taller configuration is designed for pieces up to 60 inches high.
If your artwork is unusually tall, do not assume that a longer fixture will fix the problem. Look for a light designed to throw light farther down the surface.
Distance from the artwork changes coverage
The distance between the light and the artwork matters too.
Move a light farther away and the beam spreads wider.
Move it closer and the beam gets tighter.
Frames and mats can change that distance. A deep frame pushes the light farther from the artwork than a thin frame does. That can increase coverage, but it also reduces intensity.
Situ specifically calls this out in its measuring guide.
This is one reason two pieces with the same width may need different lighting.
What about rechargeable picture lights?
The same sizing rules apply, but rechargeable lights often use more focused optics because the fixture needs to stay compact.
The Situ Rechargeable Micro Series that I carry is a good example.
Its current size recommendations are:
8-inch model
Up to 18 inches wide by 24 inches tall
11-inch model
Up to 24 inches wide by 30 inches tall
2-light model
Up to 36 inches wide by 30 inches tall, or up to 24 inches wide by 40 inches tall
Those recommendations come from the actual beam design, not from a simple fixture-to-frame ratio.
That is a much better way to size a light.
Center it over the artwork
Once you have the right size, center the fixture over the artwork.
The light should feel tied to the piece below it.
If it is noticeably off-center, you will see it immediately.
From there, adjust the light so the beam reaches the lower portion of the artwork without creating a harsh bright spot at the top.
If the light is dimmable, start low.
You can always add more.
One simple way to choose
If you are shopping for a picture light, I would use this order:
Measure the width and height of the finished artwork.
Check the manufacturer's recommended artwork size.
Make sure the light can cover the full height of the piece.
Then choose the fixture size that looks proportional to the frame.
That is more reliable than trying to force every piece of art into the same half-width rule.
Size is only half the decision. Light quality matters just as much, and I cover that in How to Choose a Picture Light for Artwork.
The light I use with my frames
I carry the Situ Rechargeable Micro Series because the sizing is based on actual artwork coverage and the light stays visually small.
It also rests on the frame, so there is no cord and no electrical work behind the wall.
If you already know the size of your artwork, the chart on the product page will point you to the right model.