Fireworks Photography: Merging Images

Published July 19th, 2011. Filed in: Fireworks Photography Guides

Fireworks are generally quite easy to photograph but getting the right fireworks in the right part of the frame is another story. In this article I’ll run through a simple but very effective post-production technique which can take a sequence of otherwise poorly balanced images and turn them into a single photograph of breathtaking beauty. It produces the equivalent of a longer exposure shot, ensuring you capture all the fireworks detail you need.


Getting started

This technique relies on one critical assumption: All of the shots to be merged are taken from exactly the same position. The use of a tripod is essential therefore and this won’t work with sequences from hand held shots, or where the camera was moved on the tripod between each shot. Similarly it is of no use with images where the camera focal length (zoom) has changed between shots.


Merging photographs – Why?

Most fireworks displays vary their action from ground level up to hundreds of feet, but annoyingly for us photographers, not all at the same time! The best images are produced when you have a nice balance of effects at various heights. So often in my images I’ll have a sequence where one shot has some low down action but a blank sky and another has lots of aerial shells but nothing below.

You might think that simply using a longer exposure at the time would fix this, but this is not an ideal solution. Why? Not only will it drastically reduce the number of photographs from a shoot but your margin for error is reduced too. And worse still, very bright fireworks in the shot could also ruin it.

What if there was an option to take shorter exposure photographs – exposing for your preferred time – then in post production create the equivalent of longer exposures as required by merging the shots? This would be the best of both worlds. Well, not only can you do this, but it’s really easy too!


Merging your images

In the image below you can see three frames taken from a sequence of fireworks over some water:

I think you can see the problems here. The first shot works well cropped right in to show the house with fireworks crossed over the top but otherwise has too much empty sky. The second image of the very next fireworks sequence has some medium height action (shortened in these fish eye images) but again lots of empty sky. Finally, some shells were launched to complete the sequence and these fill the top of the frame nicely, but the action below has stopped!

Now if I’d kept the shutter open for the entire sequence I may have captured a lovely shot with action at all levels but I could never know in advance it was going to happen in this order. Also, I did not want to risk a huge shutter time and the complications of over exposure.

So, it’s over to Adobe Photoshop and for this run through I’m using Elements, the mainstream version that’s often bundled free these days, so it’s easily accessible for most people.

Choose your shots

I tend to prefer to stick to sequential images since my aim is to enhance work I’ve already done by simply creating the equivalent of a longer exposure. This still accurately reflects the actual display. However for brochure or showcase work there is no reason why you cannot cherry pick images from any part of the display that work well together. It really depends what you are wanting to achieve. An example would be to combine images of fountains (low action), cakes (medium) and the finale (busy sky action). Remember though, this only works if the camera was not moved throughout the whole sequence of shots!

Load and combine the images into Adobe Photoshop Elements

In this example I will be loading all three of the images shown above. Ensure they are all visible in windows so you can drag between them.

Now pick one image, select the move tool, hold the shift button down and click and drag the image into one of the other photographs that are open.You’ll end up in the destination image by creating an image with two layers, the top layer (which you can see) being the image you just dragged onto it, and the bottom layer (which you cannot see now) being the image that was there to start with.

Almost done! Now repeat this by dragging the third and final image onto the dual-layered image you just created. Remember to use the shift button while clicking and dragging because this tells Photoshop to drop it into the frame exactly aligned with the edges so no tweaking of the images positions is required later.

So in this example you will now have ended up with an image that has three layers, with each layer being one of the three images you chose to combine. However you can still only see the last image you dragged, since this is the layer “on top”. You can close the other two images by the way, we don’t need those now.

Changing the layer style

Now the magic part. Ensuring your top layer is selected in the layers window, change the layer style to either screen or lighten. Now select the layer underneath and do the same. Continue until all layers except the bottom layer have been changed – you’ll leave the bottom layer alone.

As you do this you will find that the layers start to merge together! Depending on the images and whether they have much light in, you’ll need to experiment with the layer modes to see which works best. For combining lots of layers I find lighten works best because ironically it doesn’t overexpose so much. For some images with just a few layers, screen can work better. Here is the end result in Elements showing all three layers and the blended result:

In this example I used screen because although the results are brighter this brought the sky up a bit. And here it is, the final version which went from these images:

To this final result:

Boreham Hall Fireworks


Other fireworks applications

Three other fireworks related applications of this technique spring to mind, one serious and two fun. The serious one is creating beautiful brochure or showcase images for your fireworks team by using the best images from a sequence and combining them. Even if you employ a photographer there is no reason why you cannot use this technique providing the images being combined were all taken from exactly the same position.

The first less serious application is to create ultra-long exposures. I started doing these because one day I wondered what a display would look like if I kept the shutter open the whole time. Not wanting to risk taking an eight minute photograph I simply created one afterwards by combining the images. Traditional display shots like the ones above don’t really work for this, but ground level ones do. You will need a fairly powerful computer (or lots of patience) to work with a larger number of images however as it can get very bogged down!

These images for example show every single firework being fired firstly at a wedding show next to water, and secondly a wedding show in a field:

The second fun project to try is painting pictures with sparklers. You can combine separate images to build up a picture, for example the ground, tree and sun as shown in my sparkler painting article.


Non-fireworks applications

I won’t spend too long on this because there are already extensive guides easily available if you Google.

ND110 long exposure daytime shots

The ND110 (or ND1000 / ND400) is a very dark filter that enables you to take long exposures during the day to blur out water, clouds and other movement. Getting the exact exposure time is tricky, so taking a batch of images (each say 10 seconds long) and the combining them afterwards gives you maximum flexibility to build up the exposure in post production.

Star trails photographs

A star trails image like the one shown below requires an exposure time of several hours. Rather than try one single exposure which would be almost impossible on a digital camera you instead take a long succession of 30 second shots and combine them afterwards.

Happy photographing and if you have any questions, I’m always available in the UKFR Fireworks Forum or contact me.

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