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I am trying to take some product shots against a green background. The reason is that I need to be able to separate the background so the products can be photoshopped onto any background.

The problem I am having is with lighting, I can't get rid of the shadows completely and it is making it very difficult to find the edges.

I am using two studio lights 45x45 with a softbox and umbrella and the products are directly placed on the greenscreen which has an infinity cove.

I also have a flash gun at the front to provide some fill flash.

Any tips would be appreciated.

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You do not need to photograph on a green background to be able to separate them out later. Green screens are used in video so that the process can be automated since many, many images need to be altered (24 to 30 per second of video).

For still images, it is much higher quality to do manual masking to extract the objects since you only need to do it for each photo and you can adjust for issues that often appear when doing chroma keys, such as colored edge highlights (green fringing from backlighting). When you do manual masking, your can get nice white fringing instead that looks much more natural when the image is extracted.

The best results would be to use typical white softbox lighting to make sure that the background caps out at pure white while the product itself is properly exposed. You can then look at pulling any pure white if you want to try automating the process.

If you really want to stick with a green background, there isn't going to be a good way to completely remove the shadow since any light you use to fill the shadow is going to result in producing a shadow of its own. If you do blow out the background however, you can use a light specifically on the area of shadow to blow it out as well, thus eliminating the shadow. If you want to maintain the green, blowing stuff out isn't an option though.

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  • \$\begingroup\$ The keys to eliminating shadows are to separate the product/subject and the background by enough distance and then place a light that makes the background brighter than the subject. \$\endgroup\$
    – Michael C
    Commented Dec 26, 2013 at 20:42
  • \$\begingroup\$ @MichaelClark - right, but if the object is sitting on something, you are still going to have a shadow on the ground under it unless you put the lights directly even with the floor level. I got the impression we were talking about shadows under the object, not behind it. You can erase those if you are over-exposing the background by clipping it out, but getting exactly even lighting with no shadows anywhere is a near impossibility. \$\endgroup\$
    – AJ Henderson ♦
    Commented Dec 26, 2013 at 20:52
  • \$\begingroup\$ The problem I have is that the products are white (well a sort of off-white) and it is hard to get a good outline. I have to take one shot of a small white jar with it's cap leaning against the side of it and I'm finding it hard to get a good outline in the gap between the two because of the shadow. \$\endgroup\$
    – connersz
    Commented Dec 26, 2013 at 21:41
  • \$\begingroup\$ @AJ Henderson - Which should make the usefulness of a translucent light box that allows a light placed below it rather obvious, as well as placing the camera just above the plane of the floor of the light box. (Or even supporting the product with a pedestal that is smaller than the product itself, so that only a thin support is below the product. Or using clear monofilament lines to hang the product from above.) \$\endgroup\$
    – Michael C
    Commented Dec 26, 2013 at 21:44
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    \$\begingroup\$ @MichaelClark - that's a good point, though the principal that you still need to have the background over-exposed holds true since the color isn't going to be exactly uniform, but the idea of suspending it or lighting from the bottom so that the shadows go out of frame is a good point. \$\endgroup\$
    – AJ Henderson ♦
    Commented Dec 26, 2013 at 21:48
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Light creates shadows but also removes them. The key is simply to illuminate the object from below or lift the object above the background.

For the color, green and blue are often used in video but then most people have to apply the spill-removal tool after the keying tool to cancel the green cast that appears on subjects shot next to a green screen. In either case, it involves lots of manual work except that once it gets done a few times, you can repeat for sequences of frames.

A light tent is a great tool for diffusing light and they often come with interchangeable cloths to use as background. Pick one that is different from your subjects. Most of the time white is easiest because it is easiest to blow out and illuminate through. Then, place the tent over a glass table and place a lamp below but not too close. The shadow will be gone in either case but if too close, there can be a bright halo around your object.

While I use the technique just described for all my product shots, some people shoot the background through the glass. I did try and found it hard to avoid reflections and the glass had to be perfectly clear. In this case, you must illuminate the background with your lamps and make sure to keep the background empty.

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