Photoshop - Recover an overexposed image

Blog reader Mark Mayer approached me recently to ask what he could do with some images which are overexposed. He asked “I am a point and shoot camera user and like many of my friends we often take pictures that have too much sun. Although I know taking a picture facing towards the sun isn’t ideal, it’s hard to always line up the right shot”.

Mark is right. Not all of us have great digital SLRs with us all the time and we’re not always able to move into the right place to take a shot. So, if you’ve got a less than well exposed image that you like, how will you fix it?

Here is a simple fix. Depending on how much time you’re willing to spend on the image you can stop after step 2 or go on. Even if you go all the way through the fix it will take you less than five minutes. So, in my book, that’s worth the effort.

Step 1


The simplest place to start salvaging an image like this is to make a duplicate of the background layer by right clicking the layer and choose Duplicate Layer. Set the layer blend mode to Multiply.

Step 2


If the fix is too much you can adjust the opacity of this top layer downwards to get the result you like.

However, you can get even better results with a mask. Read on…

Step 3


While the duplicate a layer and set the blend mode to Multiply method is a good way to salvage an overexposed image it doesn't work perfectly on this image because the overexposure is more obvious in the areas where the sun’s rays are. If you're prepared to do a little more work you can adjust the fix to suit the image. To do this, adjust the Opacity of the top layer back to 100%.

Set the foreground color to Black and hold the Alt key as you click on the Add Layer Mask icon at the foot of the Layers palette. This adds a black filled layer mask to the layer essentially removing the fix entirely.

Switch and make white your foreground color, select a very large very soft edge brush and click on the Mask in the Layers palette and begin to brush on the fix. You’ll want the fix to be less apparent around the edges of the image and more in the area where the sunbeam is.

Step 4


You can duplicate this layer again to make a slightly more intense fix but again limiting it to where the sun’s rays are most apparent. You can also adjust the opacity of the top layer downwards if you’re getting too much of a fix.

Step 5


Once you’ve done this, you can create a flattened version of the image by clicking on the topmost layer of the image and press Ctrl + Alt + Shift + E to create a new layer containing the image data. Duplicate this layer so that you have two identical layers at the top of the document.

Select the topmost layer and choose Filter > Other > High Pass. We will use the High Pass Filter to sharpen the image because the image has a lot of color noise in it. Using this tool we can limit the sharpening to just the edges in the image and avoid sharpening the noisy areas.

Watch the image in the Preview dialog and adjust the Radius down until you see a greyscale image and so you cannot see any color. A Radius value of around 1.5 is sufficient for this image. Click Ok.

Step 6


Set the layer blend mode of this top layer to Soft Light to complete the sharpening.

Next time you’re taking a photo like this in strong sunlight, consider removing your sunglasses and place them over the camera lens. This lets you use the polarizing sunglasses as a filter over the camera lens and should cut the glare. You can do this with a point and shoot camera and with a camera phone. If you’re getting results like these with a digital SLR you should purchase a polarizing filter to use as you will get much better results with it.

Thank you to Mark Mayer for the images and this question! If you have questions, send me your question and a problem image with permission to use it as an example on my blog and I’ll see what I can do.

Note: Original photos are © Mark Mayer.

Smarter sharpening with the High Pass filter

In previous posts I have introduced the basics of sharpening in Photoshop and I also looked at a way to spot sharpen an image in Photoshop Elements using faux layer masks. In this post I want to show you the benefits of using high pass sharpening in Photoshop as an alternative to using the Unsharp mask.

The Unsharp mask has historically been the sharpening tool that most Photoshop users start out using. There are, however, different and better tools to use and one of these is the High Pass filter. One reason for this is that the Unsharp mask operates on the actual image pixels and it makes changes to those pixels. The sharpening process that makes use of the High Pass filter doesn't operate on the original image so it does not destroy the image pixels – this is particularly useful if you’re using Photoshop CS2 or earlier which doesn't offer the Smart Objects for Filters option for applying the Unsharp mask filter.

In addition, instead of sharpening the entire image as the Unsharp Mask does, using this High Pass filter process limits sharpening to the edges in the image which is where the most value can be obtained from sharpening the image.

Step 1
To see the process at work, open an image and duplicate the background layer of the image. If your image has multiple layers, add a new layer at the top of the layer stack, click it to select it and press Ctrl + Alt + Shift + E (Command + Option + Shift + E on the Mac) to fill the top layer with a flattened version of the image – without affecting the other layers.

Step 2
In the Layers palette set the blend mode of the new top layer to Overlay. This will let you see the sharpening results in place on the image in the next step.

Step 3
With the topmost layer still selected, choose Filter > Other > High Pass. This filter has one slider to adjust the Radius value. Drag the slider until you see a pretty much gray image in the preview window with the only detail being around the edges of objects in the image. If you can see color in the preview image then the radius is set too high. Typically a Radius value of well under 10 pixels should be sufficient – we used 2. Click Ok.

Step 4
The image is now sharpened – check the original against the sharpened version by clicking the Layer Visibility Icon for the top layer on and off to compare the result.

To finish the effect, adjust the Opacity of the top layer to 0 and then move it back up stopping when you have a good sharpening result. The ideal Opacity will depend on your personal preference.

If desired you can use blend modes other than Overlay, for example Soft Light and Hard Light can be equally as effective depending on the result that you are looking for.

Tip
When you are sharpening an image, adjust the image to the way you want it to look if you're planning to display the image on the web. If you're printing it you can (and should), sharpen more aggressively.

Tip

If you are using Photoshop CS3 or CS4, before you apply the High Pass filter to the top layer of the image, convert it to a Smart Object by selecting the layer and choose Filter > Convert for Smart Filters. Then apply the High Pass filter to the new smart object in the same way as I have outlined above. When you apply a filter to a Smart Object you can return later on to edit it – simply double click the filter name in the layer palette and the filter dialog opens allowing you to change the Radius value.

If you're new to sharpening, check out these recent posts:

Sharpening 101 - Understanding the basics of Sharpening

Sharpening in Lightroom 2

Photoshop Elements, Spot sharpening with a faux layer mask