Creating Lens Flare in Photoshop

When a ray of light strikes a glass-air interface inside a camera lens, most of the light is refracted and passes on to form part of the focussed image. A small but significant fraction, however, reflects back from the interface, bounces around inside the lens, and hits the film to cause unfocussed flare. Flare makes a halo or glow around bright objects, causes a general fogging of the film, and overall decreases the contrast of the image. By the use of lens coatings, designers have managed to reduce flare in modern lenses to very low levels. Low flare allows more complicated lens designs with more glass-air interfaces and increases contrast and color saturation.

In fact, there are two types of flare worth considering, light flare and dark flare. Light flare occurs in the taking lens, when the negative is being exposed, and results in light areas bleeding into darker areas. Light flare can contribute a sense of brilliance and airiness to an image if used judiciously. Dark flare occurs in the enlarging lens, when a positive print is being made. Dark flare results in black areas bleeding into lighter areas and can make a print feel somber and slightly ominous.

Like selective focus and other lens aberrations, both light and dark flare have their artistic uses. For maximum flexibility I like to capture the initial image using a modern, nearly flare-free lens. Then I scan the negative and use Photoshop tools to introduce flare if, when, and where I want.

Creating light flare:

Open a positive image file in Photoshop.

Perform a gradient selection on the image. On the Mac you do this by simultaneously holding down three keys: apple-option-tilde (the tilde key has both the ` and the ∼ symbol on it). For the PC the keystrokes are control-alt-shift-tilde. A mass of crawling lines will appear on the image indicating that the selection has been made. This gradient selection selects 100% of the brightest areas in the image, 0% of the darkest areas, and a graded percent of tones in between.

Feather the selection ( Select > Feather ). The amount of feather determines how far the white will bleed into the dark areas. I find that a pixel radius between 50 and 100 often works well.

Create a new empty layer above the image layer (click on the new layer icon at the bottom of the layers window).

From the tool palette, select the paint bucket tool. The paint bucket resides with the gradient tool. If the gradient tool is visible, click on it until the paint bucket becomes visible instead. In the list of paint bucket options, set fill to foreground (instead of pattern), mode to normal, opacity to 100%, tolerance to about 10 and turn off contiguous.

Now, make sure that the foreground color is white. With the gradient selection still on and the empty layer active, use the paint bucket to fill the empty layer with white. Actually, what will happen is that white will be painted only into the area of the gradient selection. Immediately the image will look very low-contrast and flary. You now have several options. If the overall flare level is too much, reduce the opacity of the top layer containing the flare. You can adjust it precisely to taste. Better yet, you can selectively reduce or eliminate flare in parts of the image by partially erasing the flare layer with the eraser tool. Another approach is to flatten the flare layer onto the image layer, and then use the brush tool (set to color burn) to selectively increase contrast in some areas while retaining the overall flare level.

Creating dark flare:

Once again, open the image and perform a gradient selection as described above.

Next, invert the selection ( Select > Inverse ).

Feather the selection, create an empty layer above the image layer, and use the paint bucket to fill the empty layer with black (with the gradient selection still active).

Once again, the overall level of black flare can be adjusted by changing the opacity of the flare layer. For black flare, once the overall level has been adjusted to taste, I like to flatten the image and then use the brush tool (set to color dodge) to brighten and increase the contrast of selected areas. Color dodge will cause parts of the image to simply glow against an otherwise somber background.

I used both light flare and dark flare in the Timeless Kyoto portfolio to create the feeling of dreamy antiquity that I wanted these images to express. As far as I can tell, creating flare by digital means produces an effect that is indistinguishable from that produced with a camera or enlarger lens. This allows me to capture a non-flared primary image and then decide whether or not to use flare at my leisure.