Preserve all the highlight and shadow detail in a shot

• Exposureblend.psd
• Exposureblend image one
• Exposureblend image two

An evening at the coast getting coated in seaspray and mopping up my camera with restaurant serviettes.  The final exposure blended shot preserving all the highlight and shadow detail by combining two shots.

Overview
This tutorial is designed to stop the sale of filters world wide an unlock your mind. Grad rhymes with bad and anything that is bad goes in the bin, you should know this. Grads are responsible for shoddy substandard work by computer-phobic photographers who call there pictures ‘Serene Light’ and other total self indulgent pap. I want this tutorial to turn you into a photo-bot, a data collector; an artist in the field and a technician at the PC. No more fiddling trying to line up grad lines whilst the light and action passes you by, throw you holders in the sea and come with me.

Lets Get Cracking
1. Set camera up at a high contrast scene, lets imagine a coastal sunset, no in fact have one of my shots and do this yourself (see very bottom), inky rock foreground elements and bright magenta evening sun beginning its fade into dark. Set the camera to Manual Mode (forget Av Tv etc you will soon find all these are obsolete for blending), set to evaluative metering f16 for maximum edge to edge sharpness and large depth of field, preferably focused hyperfocally (that’s another tutorial!). A tripod goes without saying, you don’t move it unless you are about to lose all your kit in freak Cornish waves AND THEN YOU RUN!!!

A straight shot.	Blown highlights and shadows, go home!

2. From now we are only going to pay attention to the histogram, forget everything else, this will be hard, but its time to use the force Luke. By pressing your shutter half way set the shutter speed so the exposure pointer is at 0 in the viewfinder lets say for theoretical sake 1 sec...

3. Lets take a photo and check the histogram.

4. The highlights are blown and the shadows have lost all detail, this is no good except I will say there are well exposed mid tones.

This wont be of much use to us as the shadows and the highlights have lost detail, the range of light is too great for the camera to capture so using a graduated ND filter to hold back the sky is an answer, but just look at the composition, how can we control the bright water with a grad? The horizon level rocks will go black in these conditions.

Take two photos and expose one for the sky and another for the black rocks, skimming the now useless grad like a flat rock into the ocean and taking a leap of faith into the world of the blend.

Ignore this shot and lets take another...

Shoot for the highlights

Highlights Image.	Featureless shadow details and preserved highlights.

5. Turn the shutter dial so the pointer now registers -2. This is the shot for the highlights, the colours / detail are all retained in the sky but the shadows are all black a featureless.

You can see the image holds all the detail in the sky, but it’s a horrible looking shot. We don’t care because it’s a beautiful looking histogram, perfectly balanced for the upper areas of the image…

See how the shadow detail is completely featureless. Have you ever seen excessive noise in the shadow details of posted shots on forums, where the photographer has used shadow recovery tools and lifted the detail on an underexposed shot similar to this? I am certain you have.

Its this type of scientific thinking that dissolves photographers into a pool of nervousness. Onwards….

Shoot for the shadows

Shadows Image.	Blown highlight details and preserved shadows. Beautiful.

6. Now take a second shot this time put the pointer at 2 by slowing the shutter speed and you should get a shot like this, detail in sky blown out but all the shadow detail in the foreground is retained

This image will look utterly horrible on your LCD too, and it will leave a sense of despair as that's the second shot you have taken that looks like crap! Well I would be patting you on the back for this one as this holds all the shadow detail.

With blown highlights, the ultimate sin will make you a saint. This shot holds all we need to stop the image blocking out in the shadows, all we have to do now is combine them when you get home.

A Quick summing up
Sometimes you may need to go even more than 2 or -2 depending on how severe the contrast range is. Using AEB (auto exposure bracketing) is a great way to start you off but can sometimes be restrictive or too severe if the light is not that extreme. If you do set to AEB, use 2 to -2. I personally think it is far better to just shoot using the histogram as the guide, altering the shutter speed to increase and decrease the exposure to suit.

By taking photos in this way (or collecting data as I sometimes feel it is) you will never see the end result in camera, and it is this that freaks people into spending £100s on grad sets. You may find it worrying, unsatisfying and therefore prefer to use grads, but the magic is nearing so leave that phone alone. Put your technician cap on, you are done with being an artist.

RAW Software
In your RAW software you should have to do very little to the images. If the histogram now reveals that the shadows / highlights were very slightly blown you can make a minor adjustment with the Exposure slider to ensure the developed TIFFs (16bit 300dpi of course) are perfect as you import them into Photoshop.

It is also vitally important that the imported files have the same white balance otherwise you will be trying to blend images with different hues, very depressing if you discover this at the end! This can also be a very useful technique, when trying to blend images that contain artificial lighting, but that’s another article in itself.

The Big Blend
Import both images into PS and sip your tea. Look at them both carefully; look at the areas of brightness and darkness and plan what you would like to see happen. Look where the water is and the highlights, look where the brightest patches of sky are. These elements are going to have to be manually blended so your approach needs to be planned.

In this image I see the sky and foreground pool must balance with the rocks. The water must always reflect the tones of the sky so a harmonious balance between these two is vital for a successful image or something will look odd. If I had used a grad, the rocks closest to the horizon would be much darker than the foreground, I would have had to use a 0.9ND or even more perhaps, as the horizon was very bright but the result would be unacceptable. Whatever you do the balance of the shadows must not be interrupted or obvious tampering will be evident. Lets begin -

1. Click on the Highlights image and press CTRL A (copy all). Flashing line around the edges will appear and the press CTRL C to copy the image to the computers clipboard (or memory if you like).

2. Click on the Shadows image and CTRL V (paste) This will paste the layer onto the Shadows file, you can now close this file to stop eating valuable memory if you wish. The highlights layer is on top. I have double clicked it in the layers palette and named it.

3. What we are going to do now is hide the pasted Highlights layer and reveal it with the Brush tool. So do the following -

4. Click on the Highlights layer. Now go to the Layers menu bar - Layer > Layer Mask > Hide All.

You will now see the top layer disappears, but its still there, just hidden. Notice in the Layers palette there is a black box next to the Highlights layer, this is your layer mask. We are now going to reveal this layer using the brush tool. Also notice the black layer has a white edge, this means layer mask is selected. If you click off this layer mask at any time (by selecting another layer for instance) you must reclick the layer mask or you will just paint colour all over your lovely picture!)

5. Select the Brush tool. Put the brush on top of the image and use the [ ] square brackets on the keypad to size the brush so it is the same width as the gap between the horizon to the top of the image. Right click on the image and ensure the Hardness is on 0, we want a soft brush as we don’t want any nasty edges to our blend.

As you have selected a layer mask the colour picker has automatically gone to black and white. This is normal as you can only use these two colours, or shades of grey. Make sure the foreground colour is set to white

	6. Now set the brush opacity to 30% and left click, making a big sweep across the picture starting in the upper right hand corner sweeping horizontally to the left. You will see the hidden image will start to reveal, but only a little. This is good, we want to work slowly and methodically. In the layers palette that sweep will show up as a grey mark across the black box. Sweep again and again and you will notice every time you do the other layer is revealed more and more, the grey becomes whiter and whiter.
	Look at what is happening to the histogram, you are lowering the levels of the bright sky and pulling back the exposure, making an image that captures light far outside the range of what the camera is capable of.
	7. Now do another sweep and this time go in and around the foreground pool. The light levels are being brought together more and more. Don’t worry if the brush clips the rocks, its got a soft edge so it wont cause any excessive darkening.

Rectifying Mistakes

Simple reverse the colour picker and make it black and go over the area you with to reverse. Simple.  Or CTRL ALT Z, keep pressing Z to go backwards through the history.

But what of the pool in the upper left hand corner, this is still too bright?

Make the brush smaller using the [ ] keys, change the brush opacity to 15% or less and carefully increase the layer mask in this area to naturally compliment the rest of the water. It's that easy. 

Adding some polish
If this is your first experience into using layers to make non permanent adjustments to images then it will cetainly open up doorways into how to process images without destruction to the image at any stage. By adding a few more totally felxible and non destructive layers, the sheen can be added tot he image even further.

Adjustment Layer to finish
Now with the image blended together you can make further standard adjustments using you own prefered methods. I personally use adjustment layers and to finish the image. Layers > Adjustment Layers > Curves

I made a very gentle ‘S’ curve in Curves. This brought in some need punch.

Then I used a Levels adjustment layer to add some mid tone lift by dragging the pointer in the centre very slightly to the left.

What's the beauty of adjustment layers? You guessed it… layer masks. You can convert adjustment layers into layer masks too and paint in the effects with the brush tool. It’s genius. When you are happy, go flatten it.

Some closing thoughts
Also realistic blending is an art, using grads is an art, many love them, I want to chuck all mine in the sea as they make me fiddle around all the time, measuring light, swinging from artist to technician, when I could simply use the histogram method alone and concentrate on my composition. In no way am I a purist with all this. I just collect data to get the desired result in any way I can, BUT respecting the overall light in the image is vital before starting the blend, think and plan what you want to see or you will overcook and make obvious errors that to the trained eye will look false.

Effectively you are doing the same as using grads but applying the grad where you want instead of working to some plastic / glass straight line. Be subtle. Remember the scene you are trying to capture is there in your head, so when you get home you can think “hang on the rocks weren’t that light, ease off.” Etc etc. It’s the key to a realistic picture, go by your judgement. Examine the scene at the time and see how things appear before you leave. Recreate the sense of emotion and grandeur.

Take regular breaks, go down stairs and speak to your wife who you will be ignoring even more than usual, have a yoghurt and watch X-Factor for 42secs before shouting at the set and returning to see whether the blend has gone way over the top. It’s a great way stop mistakes. Also, if you cant nail it that night, save a working file as a PSD and you can carry on the following day.

I spend hours on a single image, sometimes minutes like this one. It can be far more complex than this, with crazy methods of making selections and some really excellent alpha masking techniques.

YOU ARE THE ONLY PERSON WHO CAN JUDGE THIS FOR YOURSELF!

Realise the photographic world sees blending and HDR as alchemy or cheating.  When will they catch up? Photographers used to scoff at using grads many years ago. History repeats itself, ah well. Well until the EOS 1DsATOM comes out, a 40mp camera with a dynamic range of 14stops to match the pocket size 17-800 f2.8L IS, I firmly believe blending is the best technique for the job.

Another example.

Here's a shot taken with a 0.9ND Soft Step, this is the grad needed to hold back the sunshine, but just look at the end result, I didnt even bother to process it. The darkened cliffsides have lost all detail.

Here's the same shot processed (slightly different crop), exposure blended and finalised. Notice the images were taken three stops apart omn purpose, the same effect the ND grad would achieve but manually blended where it was needed. All theshadow detail is preserved through the image rendering the scene as it looked.

Further Reading

• Infomative and simple, including using Camera Raw for combining exposures.
• Layers Magazine Tutorial on Exposure Blending.
• Blending using two slides, an old approach but with the same message Michael Reichmann's Luminous Landscape Tutorial on Exposure Blending.
• Top exposure blenders - Guy Edwardes, David Noton, Darwin Wigget, Royce Howland.

(Royce and Darwin also use HDR extensively.)

Visit David Clapp's website for more information.