A written copy of the presentation given at the weekly meeting on 20th September 2016 by James Charlick.

This tutorial focuses on combining elements from different images, the most obvious example of which is adding a new sky to a landscape or architecture photograph.

It covers three main topics:

  1. How to create a selection in Photoshop using the magic wand tool.
  2. Layer masking and non-destructive editing using your new selection.
  3. Using these techniques to combine multiple photographs into a single image.

If at any point you would like to edit along to get an idea how things work for yourself right click the starting images and Save As, then open in your copy of Photoshop. The sample architecture photograph is by James Charlick, and the blue sky and clouds image is a free stock photograph from pexels.com. Don’t worry about getting perfect selections in the low-res .JPG files here though, it will be trickier than in a high-res raw file, just concentrate on what I’m doing and why, and then how you can apply the techniques to your own images. After all, this is an imperfect tutorial using imperfect images, edited in a rush for your amusement.

Screenshots of tool panels and so on are taken from Photoshop CS5, but the icons, tool names, and techniques should all be the same across Elements and other versions of Photoshop – but may be in slightly different places within the program. For example Photoshop tools are typically displayed in the top left of the program vertically and with more options horizontally also in the top right, whereas Elements has a vertical bar in the top left and then adds more options along the bottom from left to right.

Open up a new document and open these two images so that the bottom layer is the architecture photograph, and add the clouds layer above. Now hide the clouds layer and select the layer containing the architecture photograph. Your layers panel should look like this:

Firstly I will explain how to make a selection using the Magic Wand Tool. This tool allows you to make fairly detailed selections with a sensible amount of control just by clicking on an area of the photograph, which Photoshop will then assess and make a selection of the surrounding area which shares similarities with the part you clicked. For example if you click on a blue sky it should make a pretty good go at selecting that blue area but not including the land on the horizon boundary or any white clouds.

All this, however, depends on how flexible you let Photoshop be with the selection. In the tool options area there is an option called Tolerance – this is how much give and take Photoshop can use to create your selection on a scale of 0 – 255, where 0 is super precise and 255 is loose enough to probably select your whole photo.

So let’s make a selection. Set your Tolerance to ~75 and in the photo of the building click on the sky to the right of the building. You should get a selection similar to this:

Now this selection has selected the sky, but it has also gone too far and selected some of the building. This is due to the building being silver and reflecting the blue of the sky, so we need to tighten up our selection tolerance to avoid this. You can cancel your selection by going to Select / Deselect or using the keyboard shortcut Ctrl+D, and then change your Magic Wand tolerance to 10 for a much more controlled selection. Now clicking in the same area gives you this:

Great, you’ve got a nice boundary between the sky and the building. But now you’ve not selected the whole sky, so we will continue by adding to this selection with the same parameters as before – 10 tolerance. You can add to this selection by simply holding shift and then clicking where you would like to add your next selection.

All Photoshop shortcuts use Ctrl, Shift, or Alt, or a combination of these, so if in doubt there’s nothing wrong with trying them out. In this case, different selection shortcuts are:

  • Shift Click to add to current selection.
  • Alt Click to subtract from current selection.
  • Alt Shift Click to intersect with current selection (not often required).

Anyway, so using a tolerance of 10 and by Shift+Clicking across the sky we can get a nice accurate selection of the sky without any building. Click across the blue area until everything is selected.

Now I assume you’ve noticed I didn’t clean my lens. Or possibly sensor. Or both. Those little dust specs have created lovely blobs in the sky and some have not been covered by my selection. To add these areas you can use any selection tool, my preference is for the Rectangular Marquee Tool or the Polygon Lasso Tool, just make sure you hold shift to add these new selections to the current one!

As a brief aside, if you find that you’ve selected the wrong half of the image – if it’s easier to cut out the space around your object rather than the object itself for example, you can invert your selection by goring to Select / Inverse or with the shortcut Ctrl I.

Next we will un-hide the clouds layer in the layers panel, select that layer, and click on the Layer Mask button (in the layers panel there’s a small icon that is a grey rectangle with a white circle inside). This automatically creates a mask on that layer based on your current selection, so in this case it shows the clouds in the sky portion of the photograph while hiding the part that overlaps the building – all based on the selection we created. Here is my image, with the layers panel overlayed:

So let’s talk a little about layer masks. Why didn’t you just make your selection, click on the clouds layer, and hit Delete to remove the part you didn’t want?

Well for a start, who says you won’t want that back later? Masks are a way of non-destructively hiding parts of a photo without permanently deleting them. They work using greyscale alpha transparency values, which probably won’t mean much to you, but simply put that means is that anything pure black is hidden (0% opaque) and anything pure white on the mask will show through the mask (100% opaque). Grey will make things semi-transparent depending on how dark the grey is, where the darker the grey, the less information is shown through.

Now what’s left to do is to balance the image by editing the two layers so that they match a little better. Because these two elements – the sky and the building – are on separate layers I can edit them independently and quite easily.

My first thought is that the building needs a contrast boost, because the sky has some very dark areas as well as some white areas, and the building only goes from dark grey to light grey. To match I’ll boost up the blacks and lower the white point a bit using layers.

So when I talked about masks I also talked about non-destructive editing. We can do this again now while editing the files using adjustment layers, which will give us the ability to come back later and change the values and tweak the image without permanently changing the original photos.

A new layer will always be added just above the one you have selected, and in this case I want to effect only the building layer so I will click on that in the layers panel, and then click on the little black and white circle icon next to the layer mask one that looks a little like an over-simplified ying-yang. This will effect only the building because this layer is above the building, but below the sky layer. For this change you can use a Levels adjustment, a Curves adjustment, or to keep things really simple a Brightness/Contrast adjustment. They all allow different amounts of control, and my preference is Levels.

Here is a before and after of my Levels adjustment, showing both the Layers and Adjustment panels and the image itself:

So I have adjusted the levels of the image by dragging the little triangles at the bottom of the graph into different places along the histogram. The blacks  (the far left) I have brought along further into the contrast range so that the dark colours are darker, and the whites (the far right) I have brought down so that the bright areas are brighter as well.

By moving the central triangle (midtones) to the left I have brightened those too, thus overall I have added contrast and also brightened the building as a whole. This should be a closer match for the sky we’ve added.

If you wish to make changes to just the sky rather than just the building you will need to add adjustment layers above the sky layer. However this will also be above the building layer, so you will need to use masks once more to only apply to the sky portion of the image.

At any time you can select the contents of a layer or a mask by Ctrl+Clicking on that layer thumbnail in the layers panel, so Ctrl+Click on the sky layer mask thumbnail to reselect your sky. Then create your new adjustment layer above the sky layer and it will automatically mask your new adjustment layer with your current selection.

 

I hope this tutorial will show some of the basic techniques to creating a simple selection in Photoshop and what you can do with it, as well as explaining the strengths of masks and adjustment layers. I’m not going to go into much more detail here, but some of the other things presented that you may wish to look up are:

  • Using the Lassoo Tools.
  • Refining your selection by going to Select / Refine Edge, Select / Modify / Contract, and Select / Modify / Expand.
  • Advanced: Select / Colour Range (Photoshop CS1-6 and CC only)
  • Advanced: Using Channels to create selections (Photoshop CS1-6 and CC only)

If you have any questions or clarifications please ask in the contact form or in one of our weekly meetings!