Photo Technique – Seperating a low key image from background

In this exercise we are going to enhance the contrast of this image and separate the product from the background.

Open the RAW file in Camera RAW, the image of a Pure Delicacy Night-Time revitalising Cream has a limited tonal range.

We’ll leave the White Balance As Shot.

Zoom in, move the recovery slider to 50 to reduce the highlight clipping (red), move the Clarity slider to 100 to get best contrast

Before After – already looks much better!

Use the RAW Straighten tool to level the top of the bottle. Use the Crop tool to cut out the unwanted background.

Because you are doing this in RAW, your original image is not affected!

Use a linear adjustment curve to improve contrast

Move the top of the curve down to cut back the clipped highlights

Sharpen the image 150

Now save the image as a 16 bit TIFF with Adobe RGB 1998 profile and click Done

Load the TIFF file into Photoshop

Open the layers and channels pallettes, click on each colour channel, the Blue channel has the best contrast in the bottom part.

We will make two selections:

One selection of the bottle outline using the pen tool, as the bottle has nice clean edges.

Another selection at the bottom based on luminosity as the border is too rough for the pen tool.

Mark the outline then close the path and use the path selection tool to select it.

Choose the path pallette and Load Path As selection

Ctrl-Shift-I to select the inverse (backdrop)

Menu>Select>Save Selection and save the selection as a new Channel

Leaving the selection active, add a Levels adjustment layer and move the points in to get maximum contrast between the backdrop and the bottle at the bottom. Note that the unselected part of the bottle is not affected as it is masked.

Now we want to remove the bottom black strip of the bottle from the elected part.

Click on the levels 1 mask and load as selection

Use the Quick Selection tool and hold down the Alt key to remove the bottom of the bottle from the selection.

Now only the backdrop and none of the bottle is selected

Switch off the levels adjustment layer, we don’t need it anymore. Now we have smooth selection of the backdrop around the top part of the bottle and a furry one around the bottom.

Save this selection as Backdrop – full

Discard the Levels adjustment layer and the old Backdrop channel

Ctrl-C to copy and Ctrl-V to paste the backdrop as a new layer above the background.

Now select the backdrop layer and apply an Adjustment layer, for example Levels.

Alt-Ctrl-G to apply this adjustment only to the Backdrop layer, not the bottle.

Adjust the levels until the backdrop looks OK

You can use other adjustment layers eg Hue to control the backdrop.

Now apply an adjsutment layer to the Bottle (Background layer) for example Vibrance

Now you have independent control of the bottle and background and can adjsut to your heart’s content.

Posted by Barney on 3/8/2011

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