August 11, 2010

Aug 11: White Balance

Actually, 'light balance' is more appropriate.
Here's how I balanced the lighting to photograph a white-on-white-on-white subject.

The 2 important features of the subject are the quilting (stitching) and the piecework (shapes).

To capture the quilting, I need a dramatic side light to generate contrast.

The quilting pops, but the colors and shapes are invisible.

I can soften the contrast by swinging the light towards the front.

The light balance is not very good yet: bright on the left, dark on the right, too many shadows.
A softbox fill from the front right (opposite the first light) improves the balance. (please ignore the slight exposure error)

Now, I can see the shapes and the stitching. But, notice the subtle white lines (aka Seam Allowances) that criss-cross the image. These are the overlapping areas between the pieces. The quilt is double-thick in these areas, so more light is reflected.

To compensate for this, because I don't want to see the seam allowances, I need to add a backlight. I used an umbrella as a wide directional source.

From the front, the backlight produces the desired counteracting effect. The seam allowances now appear darker, as less light passes through the double-thick areas.

Balancing this backlight with the first two lights, I come up with a better image. The seam allowances are now very subtle, but remain visible enough to help define the piece work boundaries.

This final light balance produces an image that fully captures the important elements of the quilt. Both the quilting and the piece work are displayed effectively.

The set-up was about like this, exposed to include the ambient scene, (my living room), using a 70mm focal length to minimize distortion. I also used PhotoShop to square the corners and etc.

I shot this second quilt too, much more easily.

The w-o-w-o-w quilt was very difficult to photograph, but it was a rewarding challenge.

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