Photoshop CS6: HDR Workflow

This post is intended to cover two topics:
1) what is HDR
and 2) how to create HDR photos through Photoshop CS6.

Key Terms :
HDR/HDRI : High Dynamic Range Imagining.
EV : exposure value, (referring to a combination of the camera's shutter speed and aperture),
commonly referred to as 'stop'.
Ghost Artifacts : duplicated objects in the frame that appear right next to one another.


So what is HDR? If you have been just dabbling in photography or a long time photographer you may have noticed the hype surrounding the word HDR in smart phone ads and point and shoot cameras. (Although the practice itself originates from the 19th century!) It stands for High Dynamic Range, or High Dynamic Range Imagining, in which multiple exposures of the same shot in varying EVs are taken to allow a greater range of darker and lighter intensities. It essentially is a way to compensate for the cameras inability to capture the full range of intensities by intellectually stitching together different exposures.

Why is this ideal? Well HDR photos are better able to preserve and depict the diversity of luminance that more accurately reflect the real world. While this might not always be ones desired effect, it is great knowledge to know.

Many inexperienced photographers/editors (including myself at one point) tried to imitate this look by slamming the saturation, adjusting the curves to strengthen the dark and light spectrums and calling it good. This is not the same.

The good news is that creating HDR photos doesn't have to be an impossible or difficult process. Using merge to HDR pro built in to photoshop CS6 I will show you the simple steps to achieving HDR quality.

Step 1: Choose your images!

Ideally choose three images with varying EV values. It is encouraged so that each photo is near identical that you use a tripod or some sort of stabilizer when you take the photos (this is not an absolute). The three EV values should reflect a darker, a mid range and a highly exposed image to cover the range. You may find with practice this becomes easier. Another tip is if your computer you are using is a little older (or just doesn't have the ideal RAM) you can use two images so the process isn't as dreadfully slow as a slug.

Another thing to note is that differing HDR software will have different processing settings. In this format do not tweak the photos before doing this! It will make it harder for the three photos to look the same. The most you would want to do is maybe adjust the white balance and noise but make sure this is consistent with all three photos!

Step 2: Open Photoshop and begin 'merge to HDR pro'.

Go to 'file', then 'automate' then click 'merge to HDR pro'. It will ask you to either choose the files or folders. Choose accordingly the three exposures you want to work will.

Once those files are selected and added to the dialogue box make sure that 'attempt to automatically align source images' is checked. This will be particularly helpful if you did not have a tripod to stabilize your shots.

Click 'ok'.

Photoshop will get to work and create layers for each exposure selected. When done a dialogue box will open. You will likely have to realign the box a bit but what you should see is your composited image in the center, three thumbnails of the images below and a preset bar on the right side.

Step 3: Use 16 bit mode to get the most out of the UI settings.

You may notice on the right hand side it has chosen 32 bit mode for the UI settings. To get the most control choose 16 bit in the 'local adaptation' and you will notice edge glow, tone and detail and advanced options appear.

You may notice a preset bar at the top. Go ahead and play with it, but like any plug in or preset don't just pick a preset and call it good. Each photo will be different and require a customization of these presets. Don't be lazy- unless you have to...

Step 4: Get rid of those ghosts! (Ghost artifacts that is).

It will be inevitable, especially as more and more images are used that ghost artifacts will emerge. Ghost artifacts can occur when movement of objects between exposures happens. For example the breeze blows a branch slightly in a different place, or the flow of water, or movement of anything in general causes what appears like duplication. It will create this blurry messy artifact that you will want to be rid of. So be rid of it!

You will want to choose anyone of the thumbnail exposures below. It is usually recommended that you choose EV 0 as the base exposure for removing ghosts. Go ahead and choose it and check 'remove ghosts' on the right hand corner. It will take photoshop a second to process and viola! If it doesn't look right you can uncheck and try a different exposure.

Step 5: Use Edge Glow, Tone and Detail and Advanced to edit the final product.

I can not tell you exactly what setting you will need for each. What I can tell you is how each setting is designed to function. If you forget any of this remember that hovering your cursor over each setting will give you a general description and you will always get a preview!

Edge Glow: identifies high contrast areas in the photos and allows you to boost the glow while still maintaining detail to the photo. It is measured by radius which is essentially the boundaries of the glow effect. The strength would therefore be an intensity setting for the radius. (Warning: too much strength can blow out the photo). Experiment with edge smoothness to counter this.

Tone and Detail: controls the global brightness and the overall detail of the HDR look. Too much gamma can flatten out the image.

Advanced: gives you shadow, vibrance, highlight and saturation controls.

Step 6: Hit 'ok'

And there is your HDR image.


***photos to come!