What is a "bracket and blend"?
Bracket and blends are composite images...i.e. two or more separate exposures combined to make one final image. Most often, this is done to overcome limitations inherent in digital cameras. You may have seen images on the web where a person takes a picture looking out of a window in a dark building and either the window is all white but you can see what is inside the building, or you are able to see what is outside the window but the inside of the building is completely black. You may have even experienced this on your own when taking pictures...your eye is able to see both what is in the window and what is inside the building at the same time, but when you look at the picture you took one or the other is not visible. This is due to limitations in what is called "dynamic range". The amount of dynamic range the camera can see is significantly less than the human eye can see.
When a photographer decides to shoot a bracket and blend, the intention is to overcome this limitation. The photographer starts by bracketing his or her exposure...taking the same shot at two different shutter speeds, and then blending the two exposures in Photoshop. Who should shoot bracket and blends?
Anyone can shoot a bracket and blend, but they are a type of shot which requires some time and care to create successfully. Some shots look better with blown out windows or inky shadows, and some photographers want more freedom when shooting and just do not want to work so hard to get a single shot. There is nothing wrong with that. This tutorial was created for people who have an interest in this process, not to tell anyone what the "best" way to shoot is.
I have created this tutorial to show you what I consider to be the best and easiest way to create bracket and blends. I am showing you what I think works, and trying to tell you how to create images I think look good. You may discover different ways of creating these images, or find that different things look better to you. This article is simply meant as a starting point for people who don't know how to do this process. Why not just shoot film?
Good question. I shoot film as well as digital. Film, in particular black and white print film, offers much more dynamic range than a digital sensor reducing the need for techniques like this. Film also gives a different more organic look than digital. However, there are people for whom digital is more desirable to shoot for a variety of reasons including long term costs and subjects which benefit from the low noise/grain that digital offers. In addition, this technique allows for the creation of images that capture dynamic range well beyond what even black and white print film offers.
In short, there is room in photography for all types of shooters with all types of equipment and this is just one image making technique in a vast ocean of ways to create photographs. Why not HDR?
HDR is a process with the same goal as bracket and blends, but it relies on your computer to make critical decisions about how to construct the image, whereas bracketing and blending relies on your eye. The simple answer to this question is: control. Bracket and blends give you greater control over how the final image looks. Is this hard? Why is this tutorial so ridiculously long?
Doing bracket and blends is not hard at all. It does require some basic knowledge of how to use your camera, but if you can struggle through this tutorial you may find that you have learned a lot about your camera just from this one exercise. This tutorial is very long because I work in IT with a lot of novice users and when I create documentation I do so for the lowest possible level of knowledge that I can support. I wrote this tutorial to be as close to click-by-click as I possibly could. Please let me know if anything is unclear. What do I do with my camera to create the two exposures that will make up my bracket and blend?
Shooting bracket and blends is not hard. The most important thing to do when trying to shoot a bracket and blend is to shoot off a tripod. The two images you shoot must line up perfectly for the final image to look right. Shooting hand held bracket and blends may be possible, but it will complicate the blending process to a degree that it is probably not worth the time and effort involved.
When shooting, mount the camera to the tripod, ensure that the tripod is in a good stable position, and frame/compose the image how you want it to look. Once the camera is in place, you will need to shoot two images...one image should be exposed for the highlights, the other for the shadows. The best way of knowing when an image is properly exposed for one area or the other is to use your cameras histogram. Using a histogram is beyond the scope of this tutorial, but there are many explanations available online, including this excellent one from Luminous Landscape
Many digital cameras also have a feature that will cause blown highlights (areas which are overexposed and therefore totally white) to flash when reviewed on the LCD screen. This can be used to determine whether the image you shot for the highlights is capturing the detail you want or not. Barring the use of the histogram or flashing highlights, you can always just view the image on your camera's LCD screen and see whether or not you have captured the highlight/shadow detail you are looking for in that particular exposure. Just be sure that you don't bump the camera while doing so...you may even want to increase the amount of time your camera displays the image immediately after shooting it so you can evaluate the picture without even touching the camera.
With the camera mounted to the tripod you can use autofocus to focus your image, after which you may wish to flip the autofocus off to prevent the camera from refocusing before you take the second image. Set the camera to manual exposure mode, choose an aperture (f8 will deliver the sharpest results on most lenses), and then use your cameras meter to select a shutter speed. Start by metering however the camera tells you to. Once you have metered the shot, take a picture and look at the LCD screen.
If the highlights in the image are overexposed (all white), you will need to take your second shot at a faster shutter speed. Carefully increase your shutter speed without bumping the camera and take another image. Repeat this process until you have the highlight detail you're looking for. If the shadow areas in your image are underexposed (all black) then you will need to make an exposure at a longer shutter speed. Carefully reduce your shutter speed, take another shot, and check the results. Repeat as necessary.
Often, you will find that neither the highlights or the shadows are right in the first image you take. In that case, you will need to make exposures at higher *and* lower shutter speeds in order to get the result you want. Don't worry, as long as you are careful not to bump the camera when changing the exposure your images should line up well. Unless you have a hand held meter or spot meter you will often have to guess at the exposures you need to make up the final bracket and blend. I have taken 10 or more shots before just trying to get perfect exposures for both the highlights and shadows. Just take your time. OK, I have the two images, now what?
Once you have the two images, one exposed for the highlights, the other for the shadows, you must combine the images in Photoshop. Here we have two images in explorer (figure 1).
From here on out, the darker image will be referred to as the highlight image since it has all the highlight detail (figure 2).
The lighter image will be referred to as the shadow image since it contains all the shadow detail (figure 3).
These images are in TIFF format, but they can be jpegs or any other format you choose. Open both images in Photoshop. With both images open, choose the window that has the image that was exposed for the highlights, go to Select -> All
(click on the "Select" menu and then choose "All") and then go to Edit -> Copy
to copy the entire highlight image to the clipboard. (figure 4).
You can now close the highlight image window, leaving you with just the shadow image open.
Click on the window for the shadow image to be sure it's selected, then go to Edit -> Paste
to paste the highlight image into the shadow image as a new layer. You should now see the highlight image in the window instead of the shadow image, and a new layer should have been created in the layers palette named "Layer 1" (figure 5).
What we need to do now is figure out what parts of the highlight image we want to have showing. There are many ways to do this, but there's an easy way to get a good starting point. Look at the layers palette and notice that there is a little eye icon next to "Layer 1" which you just created. Click the eye to turn off the visibility of Layer 1. The shadow image should now be visible again. Look at the left side of the screen where the two little color swatches are. Just above the two swatches there are little black and white swatches and a right angle arrow. Click the little swatches (or just press "d" on your keyboard if you don't understand) and then click the right angle arrow (or just press "x" if you don't understand). You should now have white selected as your foreground color and black selected as your background color (figure 6).
With white selected as your foreground color, go to Select -> Color Range
... and ensure that "Sampled Colors" is in the "Select:" dialog. In the box, you should see a black and white image which is somewhat similar to your image. What you are trying to do in this step is to create a selection containing only the parts of the shadow image which are overexposed. Play with the "Fuziness" slider until it looks like the overexposed highlights are the only parts of the image shown in white in the little preview box. For this image, a very low Fuziness was needed, but this depends entirely on your source images (figure 7).
Click OK. You should now see that the overexposed areas of your image have the little ants crawling around them, meaning they are selected (figure 8).
Now comes the fun part. Remember the eye icon next to the highlight image you clicked to make the highlight image (Layer 1) invisible? Click the empty box next to "Layer 1" to make the highlight image visible again. You should see the highlight image reappear, and if you created your selection accurately, you will see the little ants crawling around the good parts of that image (figure 7).
You must now reselect your highlight layer. In the layers palette, click "Layer 1". Layer 1 should now be highlighted (figure 10).
On the bottom of the layers palette you will see a button that looks like a little box with a white circle in it. It will probably be the third icon from the left between the "fx" button and the black and white circle (figure 11).
Click this button. The image will change, and you will see a little black and white box appear next to layer 1. It is very important to understand what you just did. What you did is create what is called a "Layer Mask". This layer mask tells Photoshop what parts of the highlight image you want to be visible, and what parts of the highlight you want to be invisible, which allows the shadow image to show through. The little black and white box next to "Layer 1" on the layers palette is a representation of the layer mask that you created.
What is important to know is that this layer mask can now be edited. When referring to the little picture next to "Layer 1", black is transparent (allowing the shadow image to show through) and white is opaque, causing the highlight image to be displayed. Layer masks can be composed of black and white, but also of shades of gray, which we will get to in a minute.
In all likelyhood your image now has both shadow and highlight detail, but looks a bit odd (figure 12).
The problem is that the edges of the layer mask are too harsh, and there are probably areas of the highlight image showing which are too dark and simply not needed. You can begin to fix the layer mask by blurring it a bit. Click on the little box containing the black and white picture on "Layer 1" that was created when you clicked the layer mask button (figure 13). You do not want the leftmost box, which represents the image itself, but the middle box...between the left box and the text which says "Layer 1". You can see in figure 13 that there are little bars around the middle box...this means it is selected.
Now, go to Filter -> Blur -> Gaussian Blur
. Play with the slider a bit and watch how the image changes. Different images will require different amounts of blurring (figure 14).
The image looks much better now, but it's still not quite right. Most of the bracket and blends I shoot are to capture a particularly special or interesting subject, so we want to take the time to make sure the image really looks good and the illusion is convincing. This step will also show you the real power of layer masks.
See the dark area in the arch over the left window in my example, and the other dark area on the wall? Those don't look quite right, so lets get rid of them. Start by zooming in on the area that doesn't look right. Then, go to the tool palette on the left side of the screen and choose the brush tool. Next, go to the color swatches on the tool palette where we previously selected white, and click the little right angle arrow (or press "x") again so that black is now the foreground color (figure 15).
Now, set the opacity and flow for your brush. In different versions of Photoshop this will be in different places. In CS3 it will be at the top of the screen. For this example I will leave both set to 100%. Now, start using the brush to paint on the image. You will see the dark area disappear where you paint (figure 16).
In figure 16 you can see a clear line where I painted, but you will want to get rid of any harsh transitions like this. Sometimes you may find that the blurring process added a lot more of the highlight image than is necessary...basically you want to paint out any areas where there is still detail in the shadow image.
You will undoubtedly find areas where the shadow image does not have detail, but the highlight image is too dark. In these places, you will want to use the brush in a much more subtle way to edit the layer mask. Most often an opacity of 100% and a flow of between 1% and 10% will give you subtle control over the layer mask. For example, at the end of the woodwork (figure 17.) I went too far painting out the dark areas and lost my highlight detail.
So, what I can do is flip the foreground and background colors again using the little right angle arrow (or just hit the "x" key) so that white is my foreground color again, then reduce the flow of the brush to 1% and paint back in some of the highlight image (figure 18).
This isn't an exact science. In this example, I could really use a third image which isn't quite so dark, but still has some detail on the end of that woodwork. One time I manually combined 5 different images all at different exposure levels (for Sunrise Ward
) to get the look I wanted.
In any case, edit your layer mask using white to bring in the darker highlight image, and black to allow the lighter shadow image to show through. This will take time and practice to perfect. I always tell people that a small 4x5 tablet can make this process MUCH easier to do and give you better control over the brush. I have very little drawing ability, but with a bit of practice the tablet saves me hours over using a mouse to edit layer masks.
There is one more critical factor to consider when creating a bracket and blend. Many times when you view an image created with HDR tools, you will notice that the stuff outside of a window in the bright sun actually appears DARKER than the objects inside the building which are in shadow. If you are going for a lifelike, natural image this is not what you want! Blending images like this is supposed to bring in highlight detail where there was none before, but the highlights should still appear bright. In this example, the windows are clearly the brightest thing in the room, and we want them to look bright, while still maintaining detail.
There are various ways to achieve this look. You can set your paintbrush flow very low and paint black on the layer mask with a big brush to brighten the windows up a bit, but it is hard to get consistent results that way and there is a much simpler way to do it. On the layers palette, with your highlight layer selected, you will notice that there is a setting at the top called "Opacity". Click the arrow next to the opacity slider and you can change the overall opacity of your highlight layer. Mess around with the opacity until the highlights look bright and natural, while still maintaining the level of detail that you want. This step will vary in importance from image to image.
You can see the difference between the before (figure 19) and after (figure 20) images. The after image looks more natural than the original image.
The bracket and blend is essentially complete. You can now edit the image in whatever ways you choose. On this image, I wanted a little more detail on the stained glass above the window, so I created another copy of the highlight layer and masked in just the stained glass to give it a little more punch without affecting the rest of the windows. I also added a curves adjustment layer *between* the original shadow layer and the highlight layer which allowed me to do curves only on the shadow layer without affecting the windows. I am then left with essentially a finished image, needing only a bit of sharpening and cropping (figure 21).
You can now save your image in a couple of ways. If you wish to save the image with the layers and masks in place, so that you can edit them again later, you will need to save them in TIFF or Photoshop format. I recommend doing this, because you will often find (especially at first) that you will feel differently about how the image looks after leaving it and coming back to it. However, both of these formats consume huge amounts of disk space. You can also save the images as jpegs, but you will lose the layer information and be unable to re-edit the layer masks later on. To save as TIFF or Photoshop simply go to File -> Save As. To save as jpeg, click the little menu button at the top of the layers palette and choose "flatten image" (figure 22). You can now save the file as a jpeg if you wish.
This tutorial is just a basic outline of what is possible using multiple exposures and layer masks. Use your imagination and I am sure you can think of other types of images that could be combined in this way. Please let me know how I can improve this tutorial too!