Sweep & Float
8 Dec 2006

One common technique for still life and product photography is floating the subject on a background, usually a single color and often white or black. These images are then easily placed in catalogs or websites without having a whole square photo look. They seem to simply float on the page. (Somewhat ironically, my floating photo here doesn't float, since my background isn't white!) To achieve the look, you need a simple tool called a sweep. It's really not even much of a tool... it's just something that you can hang a piece of paper (or cloth) from so that it has a very gentle curve where it shifts from vertical to horizontal, which "erases" the horizon line you get with a table and a wall. You can make a sweep yourself in about 2 minutes with a good sized cardboard box. Just cut it down so that there are two perpendicular sides that are large enough to meet your needs. Then, you can prop it against books or cans to hold the one side upright, and simply tape the paper along the top.

Easy enough to make... but I actually went out and bought one. Why? Well, it's not just because I seem to get an itch around the holidays to buy stuff when technically my husband and I are on a "buying ban." It's because the sweep that I bought has some nice features and came with a whole mess of sweep paper, for a fairly reasonable price. I got the Lowel EGO Sweep, which is a slightly translucent white material. Unlike cardboard, the sweep actually lets a bit of light through the back... just enough to minimize the shadow that can happen on the vertical surface area. When shooting on white, this is particularly helpful as it saves much Photoshop clean up work.
Lowel EGO Sweep Table-top Background Support Stand & Colored Paper Backgrounds

The trick when floating a product on white is that pure white, the one that actually matches #FFFFFF, the background color of most websites, is really hard to get right out of the camera. Shadows creep in where you least expect them... and then when the image appears on real white, you see the edges of the photo and your whole floatiness goes away. When you put white paper that has some translucence to it on a dark surface... you are going to end up with shadows, and your white background is going to be darker than the white highlight on your subject. The Lowel EGO sweep doesn't completely eliminate this, but it does help.

Plus, it has a cute little "tail" on the back, so it stands up by itself and little clips to hang the paper or cloth without using tape. For $30 (US), it's a good buy. To get the whites as close to pure white in the camera as possible, I do a couple of things. First, I set my white balance. If you are using the any of the presets on your camera, then you are probably not getting neutral whites. To ensure that you are getting the cleanest white possible, it's best to shoot a test shot of a white card (I use a piece of photo paper for this) and use it to set your camera's custom white balance. By doing this, you should be able to get great white balance even in mixed lighting conditions. If you are dealing with natural light, be aware that as the light changes because the sun moves or a cloud goes by, your white balance will change. This is unavoidable and means that there will be some adjustments you'll have to do after the fact, else you will be constantly shooting a white card and resetting your WB. The other important step is checking the image histogram, if your camera can display it, to make sure that the exposure is looking good. The far right represents whites, so if there is nothing on that side of the graph, then the whites are coming out as grey. On the flip side, you don't want too much towards the right or you'll be blowing out the highlights. (more on exposure here) Once I've taken my shots, and gotten the background as close to pure white in the camera as possible, it's time for some fine tuning in Photoshop.

First, I clean up any dust/scratch kind of stuff and get the exposure and color as close to accurate on the main part of the image as I can (#2). I don't worry about the background white at this point... I just fix the subject. Then, I create a new layer with a mask. I fill the layer with 100% white (#FFFFFF) and the mask with 100% black (#000000). Filling the mask with black makes the layer 100% transparent, and the original images shows through. Then, painting on the mask, I start slowly paining white around the edges with a fairly large, very soft brush, getting as close to the subject as I can without painting over it (#3). This lets the real white show through. Then I go back and forth painting (#4) with white and black on the mask, using smaller and smaller brushes, until the subject is completely showing from the original image, but the floating area is pure white. The subject's shadow is always the trickiest part, and will always turn out best if you are close to true white in the camera. If you can't get the edge completely right, it's usually better to be a bit to light than have a darker or color casted halo.

It takes a bit of practice to get the hang of this, but the good news is that since you are working on the mask, it's easy to make corrections. In the end, you want a subject that is on pure white, but that doesn't have ugly halos of gray (#4) or blue or yellow around it. The mask should look something like a flat black shape of the image. I typically keep a TIFF version or a PSD version of the file with the layers preserved in case I need it later. It is quite a bit of work to have to repeat it all!

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(In case you were wondering, I am an Amazon affiliate, and purchases from links in this post to Amazon may earn me a nickel or two... so thanks!).

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