Part 1 - using the Background Eraser Tool
Extracting images from our photos needs some precision and detailed work to look good; it’s not something that can be rushed through if you want your extraction to look great. There are a number of ways in Photoshop CS3 this can be done, for this tutorial I’ve chosen to show you a method more suited to simpler images, like this flower.
Extracting an image from a photo using the Background Eraser Tool
In Photoshop CS3, open the photo that has the image that you want to extract.
Next you will need to manipulate the photo a little to create a better contrast between image and background, If your photo already has a strong contrast between the background and the image you can skip this part. For this tutorial I’ve used a photo of a yellow Hibiscus, it has a relatively easy edge to extract the background from. Remember the more complex the image the longer you’ll need to spend on the extraction.
- Right click on the layer image and choose 'Layer From Background'. At this point I save the file to the appropriate folder. Click on
the 'Create new fill or adjustment layer' icon and select 'Levels'. Adjust the input levels by dragging the sliders until you achieve the desired contrast between background and image. The levels will vary from photo to photo.
It doesn't matter that our flower has become darker as the levels are on their own separate layer and can be deleted when the flower has been extracted to our satisfaction.
The Background Eraser Tool erases the pixels on a layer to make it transparent by dragging the tool. But first you have to tell the tool how it's to interact with the background and image. The background eraser tool samples the colour in the centre of the brush by means of a crosshair, this is called the 'hot spot'. The colour is deleted inside the diameter of the brush.
Make sure you are on the level that you want to erase the background from as this brush overrides the lock transparency setting.
- Select the 'Background Eraser Tool' as shown below.
- Choose your brush sample on the options bar (as above) and decide what options you wish to use, for this tutorial I used a Diameter of 95px at 100% Hardness, the default 1% Spacing, 0% Angle and 100% Roundness. If you are using a tablet you can also change the setting for these, I switched both the size and tolerance off.
- Next set the limits mode for your background eraser brush
Discontigous erases the sampled colour wherever it appears under the brush.
Contiguous erases areas that contain the sample colour that are connected to one another.
Find Edges erases the sampled colours that are connected while at the same time preserving the sharpness of shape edges.
I chose 'Find Edges' for better definition of the shape.
- Setting the Tolerance to erase a higher or lower range of sampled colour, I chose a higher limit because the flower being yellow was very different in colour from the background which allowed the sampled colours to be greater.
- Check 'protect the foreground colour' box if you want to prevent erasure of areas that match the foreground colours.
- The final choice we have to make is the sampling options; choose Contiguous to sample colours continuously as you drag the tool, Once to erase only areas of the colour you first clicked on and Background Swatch to erase only the current background colour. I chose Contiguous (the two little eyedroppers).
- After selecting your options you can start to erase the background, any stray pixel will be cleaned up in our final actions, for now concentrate on cleaning the edges only. Zoom in to your image and change the eraser tool size as often as you feel necessary. I generally erase close to the edge all around the object first, then resize the tool smaller and zoom in some more and go around again.
- Next wee want to get rid of all the background and for this we can do a couple of things, first we might crop our image close to the partly extracted image or we can just change to our regular erase tool to clean it up.
- After the background has been cleaned up we need to get those stray pixels, to do this create a new layer below the image. Flood this layer with a bright’ish colour, I find a bright colour shows more strays than say white.
- Using our regular eraser tool set to about 20px to 30px and 100% opacity, you need to be able to get in to those small areas and a smaller brush size gives you better control. Clean up all around the edge of your image, zooming and resizing your eraser as needed. To see you finished results turn off the colour background layer and the Levels layer.
Here's a closer look at the finished results.
I hope you enjoyed this tutorial and look for Part 2 - Using the Lasso Tool.