Sep
7

Exposure blending in Photoshop

by
Matt Bennett

Learn how to maximise the dynamic range of your images without resorting to automated HDR plug-ins.

Before shot 1 - overexposed
Before shot 1 - overexposed
Before shot 2 - underexposed
Before shot 2 - underexposed
Final blended image
Final blended image

Exposure blending is a fantastic way to create and extend the tonal range of  an image. Often confused with HDR, exposure blending is popular with pro landscape photographers as it is a more subtle post production technique that doesn’t produce garish halos or odd colour tones.

Shooting on location, you will need a steady tripod to achieve two captures that can correctly align in Photoshop. Using your camera’s manual settings and focus, set a small aperture of around f16, this will ensure thaat both images are sharp and in focus. It is only your shutter speed that you will alter as you shoot, with one image being overexposed and one underexposed. Check your histogram at the back of your camera to ensure that one capture spikes in the shadows and the other in the highlights.

Exposing for the highlights in the scene will mean you need to underexpose your image, this will then preserve the details in the highlight areas by blowing out the shadow details. This works the exact same way in reverse when exposing for the shadows by capturing an over exposed image.

Once you have shot your two steady captures you can then open them in Photoshop where they will essentially be blended to create one image.

Step 1: Layering

Step 1
Step 1

Begin by opening both your overexposed and underexposed image in Photoshop. Using the move tool (Tools menu on the left hand side) select the underexposed image and drag it on top of the overexposed one (background layer), creating a layer.

Step 2: Add a mask

Step 2
Step 2

Ensure both images are correctly aligned on top of one another. Select the overexposed image that should be ontop and click on the ‘Add vector mask’ symbol (located along the bottom bar of the layer menu palette). A white box should appear next to the image.

Step 3: Masking out

Step 3
Step 3

Click on the white box and Select the paint bucket tool from the tools manu and ensure the foreground colour is set to black. Click on the image, this will fill the white box black and hide the underexposed image.

Step 4: Preparing the paintbrush

Step 4
Step 4

Select the paint brush tool from the tools palette and adjust the brush size and softness. To begin with you will need a bigger brush to bring back the sky. Set the foreground colour to white and set the brush opacity to around 24%.

Step 5: Painting back in

Step 5
Step 5

Ensure your selection in the layers palette is on the black box and begin painting on the image, bringing back the details and darker tones. You can adjust the brush opacity and size as you go to suit smaller areas where you don’t want to bring too much through.

Step 6: Curving to contrast

Step 6
Step 6

Once you are pleased with the exposure blend add in some punchier contrast using curves. Click on the adjustments icon (located on the adjustment layers panel) and select curves. Create an ‘S’ shape bend through the base line to add in contrast.

Step 7: Levels

Step 7
Step 7

You can add contrast to the midtones in the image using levels. Create a levels dedicated layer by clicking on the adjustments icon and selecting levels in the menu bar, move the midtone slider between the shadows and highlights until you are happy to create more realistic contrast results.

Step 8: Colour corrections

Step 8
Step 8

Correct colour casts or intensify the colour tones by adjusting the image using Colour balance. Click on the adjustments icon and select colour balance from the menu. You can work your way through the shadows, midtones and highlights and adjust the colour balance sliders.

Step 9: Flatten layers

Step 9
Step 9

Once you are happy with the final results save your image as photoshop file, this way you will retain the layers should you wish to go back and re-edit. Now flatten the layers in order to get one image layer, go to, Layer>Flatten image.

Step 10: Cropping in

Step 10
Step 10

Now you have compressed the layers it will be easier to crop in and create a cleaner composition. Select the crop tool from the tools pallette, click on the top left hand corner of the image dragging the cursor diagonally down to the bottom corner. Hold down the shift key to retain the image size and slowly bring up the corners until you are happy.

Step 11: Cloning

Step 11
Step 11

Duplicate the background layer so you don’t make any adjustments to the orignal image. Clone out the distracting elements from the image using the clone stamp tool. Selct the clone stamp from the tools palette and adjust the brush size to suit what you want to remove, keep the edges soft with the opacity high. Hold down the alt key and select the area next to the mark you want to remove then place the cursor over the mark and brush it away.

Step 12: Sharpen Up

Step 12
Step 12

Once you have made all the final adjustments to your image sharpen it to give a cleaner more professional finish. Go to, Filters>Sahrpen>Un sharp mask and put the amount up to 100% slowly bringing up the radius to around 1.8 or until happy with the results

Step 13: Flatten, resize and save

Step 13
Step 13

You can flatten the last few layers, the same way as before and resize the image to suit its intended out put. Go to, Image>Image size> Resolution, type in 300 pixels/inch if you want to print or 72 pixel/per inch for web upload. Now save your final image as a Jpeg.

TOP SHOOTING TIP – USE YOUR HISTOGRAM!

When shooting your two exposures, keep an eye on your histogram at the back of the camera. You will want your underexposed image to spike in the shadows (left hand side of the histogram) whilst your overexposed image should spike at the opposite end in the highlights.

You don’t want to loose too much midtone detail either so ensure that there is enough mountainous range in the middle of each. Once compressed in photoshop your final image histogram will display a more even range.

Histogram
Histogram
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