Changing background of a photo

Recently, I completed photographing a party event. This was indoors and I had to use flash. Unfortunately, I didn’t have my diffuser and ended up with quite a many photos with shadows in the background. It was an effort to remove the shadows of the photos. Typically professional photographers use a software such as Adobe Photoshop CS5 or equivalent to get this job done which can be an expensive piece of software. However, we have help in the form of Opensource. Opensource is an effort to develop freely available software. Efforts to develop and maintain the software is put in by volunteers. It is crowd-sourcing effort, but it is all free – you can say that.

So how do you go about doing this – i.e., replacing background. I had explained this in one of the previous posts, but I am doing it again. However, we will use the opensource software called The concepts are still the same. Here are the main steps:

capture11) You have to open the photo in Figure 1.

What I want to do here is to replace the background behind the person standing in front of the microphone. We will remove the curtain part of the background, while retaining the banner.





2) The next step is to use the Magic Wand tool. You will find this in the Tools palette, standing at fourth from the top, in the first column. You can get to the Tools palette by Capture2click the first icon on the icon tool bar near the top right. The Magic Wand tool is used to select areas on the image. Once you click on this, the cursor changes to a ‘+’ sign. Also you will notice a Tolerance drop down pop up in the tool bar above the photo. The tolerance level specifies how tolerant the selection will be once you click on an area. Say you click on the black region besides the subject, the will select all adjacent area of the same color, but the tolerance will limit how much the color varies for selections. The higher the limit/number, the more of the variations in the black colored area the tool will select. In the picture below, you will see the selected area as highlighted by the white, when I clicked on the area below the banner.


Capture33) The next step is to select as much of the area excluding the subject as possible. You do this so that the Magic Wand tool ‘adds’ to the already selected area. This is done by holding down the Ctrl key. This is referred to as additive selection. Just click away on different spots while holding down the control key and you will see the selected area expanding. This is how it will look after most of the curtain behind the subject is selected.




4) Now hit the Delete key. It will expose some of the black areas not selected. You can keep clicking with the tool till you select all the area you want erased and hit the Delete key again. Another way of speeding up the process is to increase the tolerance level, but this can eat away areas of the subject that are adjacent, like the belt which is also black in color. This is where the Eraser tool comes in handy.


Capture45) Select the Eraser tool from the palette. This tool looks exactly like an eraser and is two below the Magic Wand in the second column. Once you select the Eraser, you will see a Brush Width drop down popping up on the tool bar. By increasing the number in the drop down, you increase the width of the eraser. This makes it easier to erase a larger area. Just clicking on the image, will erase area enclosed by the eraser. This shows up as checkered area on the image. As you get closer to the subject, you will want to zoom in (View-Zoom in from the menu) and/or reduce the brush width. In the figure below, you will see the result so far of most of the background – the curtain – removed.


Capture66) Now to replace the background.  What we need to do is to add a Layer to our work. A layer is nothing but just that – a surface where one object can sit. In our case, we will have two layers, one with the edited photo and another with our choice of background. First, make sure you also click the layers icon on the tool bar near the top right. This icon is next to the clock in our examples (click on the images to see a larger picture). We then select an available image as a background as our layer. From the Layers menu, select Import from file and select the image file. We now see the layers panel in the adjacent image and the imported image on a different layer. However, the imported image is overlapping or sitting over our subject image.


Capture77) Next step we do is grab the handle at the bottom right corner of our background image and drag it down and to the right with the mouse so as to overlap with our edited image so that the sizes are equal. Wait! What happened to our edited image? It just went to the behind and has disappeared from our view.







8)   To get it back, make sure the background image is highlighted in the layers menu and click the down arrow below. What this does is to ‘push’ the background layer behind.







Finally, we have the background replaced as we wanted to!!

This is the essence of the idea of replacing a background on one of your photos. Our finished photo isn’t perfect, but we can work on it more to make it more perfect using the Magic Tool, it’s tolerance level, additive selections, the Eraser tool and layers functionality. Here are more, much clear examples

IMG_7519- AshBGReplaced2 IMG_7519- AshBGReplaced3 IMG_7519- AshBGReplaced4

Thank you for your comments. Comments are moderated before they are published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.