Alien Iris Tutorial

This tutorial covers shooting a light object against a black background with two studio lights for illumination. It fixes problems caused by mistakes made while shooting against a black matboard background with the wrong white balance settings.

The digram below shows the shooting setup. The iris was in a vase (red) on a small table about three feet from a wall. A piece of black matboard was stacked against the wall on a couple of cardboard boxes to raise it to the correct height. Two 600 watt tungsten lights (blue) with built-in softboxes were positioned as shown in the diagram below. The light on the right was positioned on its stand so that it was slightly lower than the height of the iris, while the light on the left was positioned slightly higher. The two softlights put out enough illumination that the camera (purple) could be easily handheld for the shot.


The camera was not set for a tungsten light source and the black matboard was not positioned quite properly. The original photo on the left below shows the results - a warm cast and a dark gray area on the left side of the photo. The dark gray can be difficult to see on some monitors, so the slice of the photo in the center shows the area with the contrast and brightness boosted. The first set of corrections are to adjust the color. In Photoshop Elements, Enhance > Auto Levels, Enhance > Auto Color Correction, and Enhance > Auto Contrast were run in succession to remove the warm color cast. The result is the image on the right.

Original	Background Error	Color Cast Removed

Fixing the color error has changed the gray area in the background to blue. The slice of the photo on the left below is from the area in the center photo above where the longest petal crosses the gray area. In addition to the now blue pixels in that area, other blue (originally dark gray) pixels can be seen near the upper edge of the petal. These pixels are caused by "blooming". The brightness of the pixels in the area with the white petal "spilled over" into the pixels in the dark area. (This happens while the photo is being recorded in the camera, when "extra" light spills into neighboring sensors.)

Background Error and Blooming	Selected Area

This problem can be fixed by using Enhance > Adjust Color > Replace Color, but a selection needs to be made first to prevent similar colored areas on the stem and leaves from being replaced at the same time. The photo on the right above shows the selection, which excludes the dark areas on the stem and leaves. The selection was created by using the Magic Wand tool with the "Contiguous" box checked at several different tolerances and using the Selection Brush tool to clean up the result. The eyedropper in the Replace Color was clicked on a blue pixel near a petal. Fuzziness was set to 90, and Hue and Saturation were left at zero. Lightness was set to -100 to completely darken the pixels for the final result at the top of the page.