Photo Stacking is a post-processing technic, which allows us to blend several shots together. It has some advantages, some disadvantages, it is seen by many photographers as a way to “cheat” your photos, but it can also be useful! …and creative!

When can it be useful?
Imagine that you want to do a lot of light painting – lets say you need a couple of minutes to do all your stuff – on a place with some ambient light. If you shoot it with a long exposure maybe you will get a blown-out photo from all that ambient light coming through your lens and if you shoot a shorter exposure maybe you won’t have time for all your light painting.
You can try to fiddle with your camera settings – and I advise you to – and maybe you will be able to find a good compromise, which will allow you to keep the ambient light dim while still having time for your Light Painting. This would be maybe the best solution. But, still, sometimes it doesn’t work, so Photo Stacking is a very useful technic to know!

How do you go about doing it?
The easiest way is to think in layers. Imagine that want to take a photo on a street with 4 Ball of Light. You will have 5 layers:

  • – ambient / background exposure;
  • – ball of light #1
  • – ball of light #2
  • – ball of light #3
  • – ball of light #4

Then you just need to go to the computer and blend them all together. And to explain you that part I thought it would be better to use an example.

The other day I went out with my friend Thomas to the forest to take some photos. For some creative reasons we decided to use photo stacking to make this photo:

Light Painting Photo by Luis Pato and Thomas Lange

Ghost, by Luis Pato and Thomas Lange

Lets see how we did it.

We discussed the idea and planned it out in layers like this:

  • – Ambient Exposure (we used this exposure also for the Ball of Light and the smoke);
  • – Person 1 (right side);
  • – Cloud over person 1;
  • – Person 2 (left side);
  • – Ghost over Person 2;

We took for each layer several shots, but after some selection we ended up with this ones:

Light Painting Photo by Luis Pato and Thomas Lange

5 shots to stack together

Back home I uploaded them to my computer. Then it was time to put them together.
Open all the photos in photoshop, in one document, each photo as a separate layer and organize them to your liking.
I like to name them, to have the Ambient Exposure as bottom layer and, when necessary, to group layers (maybe you have several layers for the room, several layers with smoke, several layers painting trees,…). This will help to keep things simple.

layers in photoshop

organized layers

Select all layers and go to Edit > Auto-Align Layers. Even using a tripod sometimes there are some little movements, so it is always good to align the photos.

auto-align layers

Auto-Align Layers

Now it’s time to see some magic.
Select the top layer and on the Layer’s Blending Mode choose: Lighten! Voilá!

Now Photoshop will show from that top layer only the pixels which are brighter as the corresponding pixels on the layers below.

Lighten blending mode

set Layer Blending Mode to LIGHTEN

Do the same with all the other layers (you don’t need to do it to the bottom layer) and you’re done!

5 photos stacked

all 5 photos stacked using Lighten Blending Mode

Look at the photo carefully (the best is using 100% zoom), in some places you might want to use masks to mask out some part that you don’t want on the photo, to make something more visible or even to hide it, like here:

person masked body

sloppy masking of Person 1

And that’s it!

The stacking process is done. If you want you can either flatten your image or use some adjustment layers to make it more accurate to what you were looking for…

stacked photos

the whole thing

You can also download the free PDF Tutorial here:
Photostacking tutorial

We would love to see any images that you have made using this creative technic. Maybe you can post some here on our comments…




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