A few weeks ago, I wrote an article comparing Exposure Blending to HDR. In that article, I wrote about how exposure blending does not always have to be complicated.
In this article, I wanted to look at how you can blend multiple exposures using Photoshop. We will look at techniques ranging from easy to more advanced ones.
Why do you want to blend multiple exposures in Photoshop?
Simply put, our cameras are not always capable of capturing the entire dynamic range of a scene. In these instances, you can shoot a set of bracketed exposures. You can then blend those exposures in photoshop, using one of these techniques. Doing this should result in a correctly exposed image, with the complete dynamic range.
How To Shoot For Exposure Blending?
To create an exposure blended image in photoshop, you are going to need a set of bracketed exposures. These images should cover your scene’s entire dynamic range, from underexposed ones that cover the highlights to overexposed ones for the shadows.
The most common way of bracketing is to set your aperture and ISO to the appropriate settings. You can then change your shutter speed to create the brackets.
Most cameras will have an auto-exposure bracketing feature that you can use to do this. However, you can create them manually if your camera does not have this feature.
Auto Exposure Bracketing
Most digital cameras will have this function, and it is typically called AEB in the menus. In the settings for AEB, you can select the number of exposures that you want to bracket. You can also choose the number of stops between each step and the order of those brackets. The brackets’ order does not matter, but my preference is to capture from underexposed to overexposed. That allows me to see the images in a logical order once imported into Lightroom.
When doing it manually, you can use the exposure compensation function in the camera. If your camera does not have exposure compensation, you can set your camera to manual mode. You can then set aperture and ISO, and then adjust the shutter speed to under and overexposure the image.
How Many Brackets Do You Need?
The number of brackets required will depend on the dynamic range of the scene. The higher the dynamic range, the more brackets you are going to need. Sometimes you might need more under or overexposed brackets to cover the entire dynamic range.
The best way to ensure that you cover the entire dynamic range is by looking at each image histogram. You are looking for your most underexposed image covering the highlights, and that there is no clipping. You also want to ensure that your most overexposed image covers the shadows.
In most cases, you will be able to use only two brackets in your blend. But if the dynamic range is too large, you might need some more brackets when blending. Make sure you have an even distribution of exposures that covers the entire dynamic range. My preference is to bracket by either one or two stops at most between each image. That allows me to achieve a smooth exposure blend in photoshop.
Use Your Tripod
You can shoot handheld and align your images in photoshop. However, I would always recommend using a tripod when shooting multiple exposures. Not only will a tripod help you to line up your images better, but it will also help ensure that they are all sharp.
How To Blend Exposures In Photoshop?
For the sake of this tutorial, we are going to be using two images for all the blending. It is worth noting, though, that you will need more than two images in some instances. In those cases, the process is the same, though. You will have to blend one image at a time to achieve your final result.
It is also worth noting that I chose this scene because it is possible to blend it using all these techniques. That will not always be the case for all your images. Some methods will not work on all your photographs, and in some cases, there will be an obvious standout method.
Before starting, you want to make sure you have both images layered in photoshop. You also want to ensure that you align them, even if you used a tripod while shooting. Although my preference is to always have the dark layer on top, the layers’ order is not important.
Freehand blending is the easiest method for blending two exposures in photoshop. You can successfully use it on images that have a clear transition between light and dark areas. Or on images where there are no delicate, subtle, or complicated differences in light.
This process involves you freely painting with a brush on a layer mask. By painting, you will either hide or reveal details of the masked layer. You will get the best results by taking your time and making multiple brush stokes with a low opacity.
Steps for Freehand Blending:
- This first thing is to create a black layer mask on the top layer in photoshop.
- Select the brush tool and set the opacity to something low, like 20%. Also, ensure that your brush has a hardness value of 0%. That ensures that you will get a feathered brush stroke.
- Set the brush color to white.
- Select the layer mask we created and start to paint to reveal the highlights.
- Because we set the opacity to 20%, you will have to make multiple passes to reveal more details. You can adjust the opacity up or down to help control the amount of detail exposed with each pass.
- If you have gone too far or you have made a mistake, you can switch to a black brush and paint some of the mask back in.
A gradient mask will produce the same results as a graduated neutral density filter. The difference is that you can control the position in photoshop after taking the image. You can also apply multiple gradients at different places or angles. That is something that is not easy to do with actual filters.
You will, however, have the same problems you will with a GND filter. The gradient will affect anything protruding above the horizon. Depending on the complexity of the object, you can combine a gradient with freehand blending. You can then paint out some of the gradient on those objects.
Steps for Gradient Mask Blending:
- Create a white layer mask on the top layer in photoshop.
- Select the gradient tool, set it to a linear gradient.
- Set your foreground color to white and the background color to black.
- Make sure you have the layer mask selected. Then draw a line from the top to the bottom where you want the gradient transition to appear. The longer the line you draw, the bigger the transition. You can hold shift while drawing to ensure your line is straight.
The basic premise of Apply Image is that it applies a blend mode to a target from a source. The target can be a Layer, Layer Mask or a Channel.
There are many settings for Apply Image in photoshop, but to blend these two exposures, we will keep it simple.
Steps for Apply Image Blending:
- First, create a white mask on the top layer.
- Secondly, select the mask and hide the top layer.
- The next thing is to select Apply Image from the Image menu. Apply the settings in the popup according to the settings in the screenshot below.
- If you have a darker image on top, ensure that Invert is not selected. However, if you have a lighter image on top, you can select Invert to blend in the shadow details.
- If you feel that the effect is not strong enough, you can rerun Apply Image to increase the mask.
Blend If is a tool that allows you to blend two layers based on the information in either layer. It uses the channels in your image to do the blending. It is one of the most straightforward tools to use for sky replacements, and hence it is also great for exposure blending.
You may find that you can’t complete the entire blend with the Blend If tool in some cases. In those cases, it should put you in an excellent position to complete the blend using freehand blending.
Steps for Blend If Blending:
- Double click the top layer to open up the layer styles and select blending options from the top.
- At the bottom, you will see the Blend If controls. Make sure to select “Grey” in the dropdown. That ensures that we are using the layer’s luminosity channel to do the blending.
- Start by moving the black selector under “This Layer” to the right. As you move the selector, you should start seeing the shadow detail disappear from the layer.
- To make a more gradual selection, you can “alt+Click(Win) or option+click(Mac)” to break the selector in two. That will give a more natural blend.
The beauty of using luminosity masks for exposure blending in photoshop, is that you can use them in so many ways. You can apply the entire selection to a mask, like Apply Image. On the other hand you can use the mask as a selection and then use it as a template to freehand paint in only the areas you want. You are also able to alter the mask and refine it the way you want before applying or selecting it.
Another benefit of luminosity masks is that you can use them to mask anything in your image, whether that is a pixel layer or an adjustment layer. You have fine control over any adjustments you make in your image by applying a luminosity mask to a layer.
Steps for Luminosity Mask Blending:
- Create a black mask on the top layer.
- Generate your luminosity masks. Read this article if you need to learn how to create luminosity masks in photoshop.
- Next, select an appropriate mask by “cntr+clicking(Win) or cmd+clicking(Mac)” to select your mask.
- With a white brush and low opacity, you can start to paint in the areas of the layer you want to reveal. Depending on the type of mask you have selected, this could either be highlight or shadow details.
When Not To Use These Exposure Blending Techniques
It is essential to realize that you should not blend all your images. If your photo covers the entire dynamic range, you will not increase it through exposure blending.
There might still be quality benefits from using exposure blending, though. So it is essential to understand your camera and both your highlight and shadow details. If your camera is prone to noise in the shadows, you will be able to remove it by blending in an overexposed image. Doing this will replace the shadow details with the clean shadows from the overexposed image.
As you can see, there are multiple techniques in photoshop for blending exposures. Getting started does not have to be complicated. Knowing what you are capable of in photoshop will also help you when you are taking photographs. If you are new to blending, photographing less complicated scenes will allow you to achieve a smoother blend once you are editing in photoshop.
Exposure blending is not a one size fits all approach. You will be best served by learning many techniques, as this will allow you to pick the best methods for a given image. Sometimes the most obvious solution is not the best, but be careful not to over complicate things. You should always choose the right approach for the situation.
An important thing to remember is that exposure blend is only the beginning and not the final result. You will still need to process your image the same as you would any other. It will only give you a base to start from for your creative editing.
Over To You
How many of these techniques have you tried, and which is your favorite? Let me know in the comments below?