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Leap ahead with these five quick tips for using the Urban Lightscape Photoshop plugin to correct exposure and balance lighting in your pictures.

Figure 1: Placing control points close together relative to the Spread setting can cause stark contrast in lighting.

Tip #1: Know when to use the smoothness slider

Placing two or more control points close together with respect to the setting of the Spread slider can trigger a sharp contrast in light and dark (see Figure 1). Increase the Smoothness slider to fix the problem while keeping the overall effect faithful to your intent.

Tip #2: Sharpen after, not before

Urban Lightscape relies on edge information to propagate and interpolate adjustments between control points. The purpose of sharpening is to exaggerate edges, but this interferes with Urban Lightscape too. The end result is more grain than you may like, so sharpen after using the plugin, rather than before, if this isn’t what you want.

Tip #3: Save contrast adjustments for later

Contrast adjustment is what Urban Lightscape achieves, but spatially rather than pixel-by-pixel. Increasing the contrast of an image may darken areas that you will later lighten with Urban Lightscape, amplifying noise. Consider deferring your final contrast adjustments until after you have used Urban Lightscape to get the spatial balance right.

Tip #4: Avoid JPEG images if you can

JPEG compression artifacts that are imperceptible to the human eye can still mislead the edge detection used by Urban Lightscape, and degrade its output. Within Photoshop, prefer using the RAW files produced by your camera, if available, rather than compressed JPEG images.

Tip #5: Use the sRGB colour space

The Urban Lightscape Photoshop plugin uses the sRGB colour space internally. Elsewhere in Photoshop, you may be using a different colour space, such as Adobe RGB. This mismatch will degrade the faithfulness of the preview image in Urban Lightscape, usually producing noticeably dull colours. To ensure that you are using sRGB, use the Edit > Convert to Profile menu item in Photoshop, and select "sRGB IEC61966-2.1".

Following the above tips should get you well on the way to getting the most out of the Urban Lightscape Photoshop plugin!

Urban Lightscape 1.1.1 and Tintii 2.6.2 are now available for download. These new updates fix plugin support for 32-bit versions of Photoshop CS4 and earlier on Mac OS X.

Urban Lightscape 1.1.0 is now available, with significant performance improvements on all platforms, most noticeable when dragging control points around a photo. Download the new version here.

Looking at the promotional screenshots for Urban Lightscape, the astute, well-travelled and Vietnamese will have no trouble guessing where I’ve been most recently. As I develop some of the photos from the trip, I thought it an opportune time to share some of the ways I’m putting Urban Lightscape to use in my own workflow, and provide a few tips for getting the most out of it.

Take this photo (Figure 1) from the Reunification Palace in Ho Chi Minh city. The vase in the foreground is meant to be the focal point of the capture, but it’s also the dullest part of the piece. Global adjustments to brightness, contrast and curves in Adobe Photoshop’s Camera Raw only get me so far (Figure 2). I need to actually enhance brightness locally around the vase, and it is for this sort of adjustment that Urban Lightscape shines.

Figure 1: Original photo as taken off the camera, lighting is dull.

Figure 2: Global adjustments only get so far, the foreground vase is still dull.

Bringing up the Urban Lightscape filter plugin from within Photoshop, I begin by adding the first control point on the vase itself (Figure 3). Double-clicking on the vase and dragging the mouse cursor up increases the light in this area. The adjustment bleeds somewhat beyond the vase into the adjoining carpet on the left, and control points 2 and 3 are placed to smooth the effect, the bright yellow carpet producing a nice contrast with the greens in the vase. The effect around control point 1 is halted at the sharp edge that rings the neck of the vase; control point 4 above lightens its top. Finally, the painting in the background has some nice colour, and control point 5 brightens that up. The spread slider is increased a little to fill the adjustments throughout the picture, giving the final product (Figure 4).

Figure 3: Control points placed on the image to make local brightness adjustments.

Figure 4: The final result after Urban Lightscape adjustments.

A brief parting in an overcast sky set the scene for this shot at Tu Doc tomb outside Hue. While natural light pops the subject (Figure 6) compared to a photo taken just moments before (Figure 5), a dimness creeps in from the right, and in total the foreground has been underexposed, so as not to bleach the sky. Urban Lightscape can be used here to accentuate this spatial contrast of light.

Figure 5: Original snapshot, natural light is poor.

Figure 6: A lucky break in the clouds casts the sun onto the summer house!

A few carefully placed control points achieve this and correct the balance of light to the right for a better composition. The image has been sharpened, and blues and greens further saturated, to finish up (Figure 7).

Figure 7: The enhanced picture after local lightness adjustments.

These two simple examples show three of the main uses of Urban Lightscape: correcting exposure, introducing artificial light sources, and exaggerating contrast in natural light.

See the two photographs in this tutorial on Flickr: The Yellow Room and Emperors and Poetry.