Background Eraser Tool



The background eraser tool lives with the eraser tool and the keyboard shortcut is E.  What it is supposed to do is provide an easy and effective method to remove a background.

It is most suitable for images with a good contrast between the background and the object you want to keep.It works by turning some of the colored pixels transparent and if it is used with care then an object can be removed from a background.

At its simplest, just grab the Background Eraser, zoom in and start removing the unwanted pixels.  With this procedure the Background Layer is turned into a normal layer because you cannot erase on the Background layer - this is just one of the things that Photoshop Elements does ...

Intuitively, this seems like a very useful, very versatile tool that is easy to use and will create great results.  In some cases that is true and in others there are much better methods to remove a background.

It's probably best to spend a bit of time looking at the different options when using the Background Eraser and then try it out with some live images.

Options

Brush Palette

Like a lot of the tools in Photoshop Elements, the Background Eraser has a number of differentbackground eraser options options and it will react to the pressure applied to a Wacom pen (Bamboo or Intuos).

This palette is in the top left corner of the Elements screen (Version 10). 

It allows you to change the ...
  • Diameter
  • Hardness
  • Spacing
  • Tip Shape
  • Angle
At the bottom of the screen there are addional options which allow you to set the size of the brush and the Tolerance to change with Pen Pressure.  There's also a setting for Stylus Wheel if you are using an Airbrush Tool with your Intuos tablet.

In this screen shot (it seems to be the default setting) both the Size of the Eraser and the Tolerance will increase with Pen Pressure and these are the settings I initially started using.  Together they were somewhat problematic, however.

Changing size with pressure is easy to understand - press harder and the size of the area being affected becomes larger.

Tolerance is a different matter.  The Tolerance dictates how similar a color in the circle has to be to the color under the hotspot to be erased.

  • A low Tolerance setting means the color in the circle has to be very similar to the color under the hotspot to be erased.
  • A high Tolerance setting means there will be a much larger range of colors similar to the color under the hotspot erased.

Having both of them react to Pen Pressure resulted in some strange behaviors and I eventually settled on having one or the other set to Pressure but rarely both.


Brush Tip

background eraser tip

When you select the Background eraser and move over the pictue this is what you see.

The cross in the center of the circle is the hotspot and the circle is the area that will be erased when you use the tool.

Pixels that are within the circle that are of similar value (depending on the Tolerance) to the pixels under the hotspot will be removed. 

Straightforward, right?





Options Bar

background eraser options


The last thing to look at is the Limits setting (Contiguous or Discontiguous).
  • Contiguous means that whatever color is under the hotspot and within the circle will be erased but the pixels have to be adjacent or next to one another.  The tool won't jump over things (like strands of hair or tree branches) with the Limits set to Contiguous.

  • When the Limits is set to Discontiguous it instructs Elements to erase a color under the hotspot that is within the circle even if it has to jump over a strand of hair or a tree branch or whatever - as long as the color is under the circle then it will be erased.
The last setting is the Tolerance and as stated earlier, Tolerance dictates how similar a color in the circle has to be to the color under the hotspot to be erased.
  • A low Tolerance setting means the color in the circle has to be very similar to the color under the hotspot to be erased.
  • A high Tolerance setting means there will be a much larger range of colors similar to the color under the hotspot erased.
NOTE:  The Photoshop Help file is short and succint when describing how to use the Background Eraser tool which is something  that Help files tend to do.  In practice the tool doesn't work quite the same as implied by the Help file. 

This tool works best with an image that has moderate to high contrast between the foreground (that which you want to keep) and the background - I've used this eraser with many different images and the only times it works the way I figure it should based on the Help file is when it's a high contrast image - just so you know.

OK - enough theory - let's look at the Background Eraser in action ...

An Simple Example
or is it simple?


Here's a sample that is not suitable for the Magic Eraser but may well work with the Background Eraser ...


background eraser escalade


Its actually a busy background with at least eight different contrast areas betwen the background and the Escalade.  The approach needs to be modified depending on the contrast of an area.

Starting Out

I started the project in the top left corner of the car where the bricks meet the top of the Escalade.  The settings were as follows ...
  • Limits - Contiguous
  • Pen Pressure - changes Tolerance with Pressure
  • Tolerance - maximum 29%
  • After the first pass of the Background Eraser the Background layer was changed to a normal raster layer and re-named Layer 0 - all of this was done automatically by Elements.  At this point a new layer was added above Layer 0, moved to the bottom of the stack and a color was added which is a good way to make sure the eraser is doing what it should (I chose a nice blue).
  • The Undo History Palette was always open and it was used a lot.  I found that the eraser could make mistakes (never me) and it was necessary to go back a few steps.

background eraser close viewThese settings worked quite well.  If the Limits were set to Discontiguous as my Pen entered the dark area at the back of the vehicle and if the pen size extened over the side window this is what happens ...

As you can see the Discontiguos setting will jump over things and in the situation we don't really want that do we?

After all the Background Eraser has now removed part of the back window.

As you are working with this eraser keep evaluating the areas that will be done next so the settings can be changed if necessary.

With the Limits set at Contiguous this won't happen.


background hose vacuum


The next challenge occurred right below this area where the red hose of the vacuum cleaner in the background can be seen immediately above the bright red taillight (as you can see from this close up).

This took a lot of very close work with the Tolerance in single digits and Pen Pressure changed from Tolerance to Size - and even then I had to go back to it a bunch of times to get it right.  It also helped to be using an Intuos tablet for this project.

It was good to have the Undo History readily available on screen.

These are the kinds of difficulties you will face when using this method of background removal.  It looks easy but there can be a lot of fiddly work involved and here's and idea - only use the Background Eraser to outline the part of the image you want to keep and then use the normal Eraser to do the rest of the job.

Here'show it looks after the first go round with the Background Eraser ...


background eraser first through


background eraser holesA closer look at the outline of the Escalade shows some holes in the part that was erased with the Background Eraser.

This will be cleaned up in the final phase - the clean up of the image.

Getting to this point took a few hours each day for three days which seems to be different from what is implied in the Help file.


Escalade Clean Up

The clean up was done with the normal eraser and the clone tool.

The normal eraser was used to remove the big bits that were not really involved with the outline of the Escalad and to fix any bits that were not removed by the Background Eraser

The Clone Tool was used to get rid of that unsightly pole that is visible through the front windshield that is behind the dirvers door window.

Clean up took about 20 minutes and as I was working at it, it occurred to me that it would probably have been just as easy to promote the Background layer to a normal layer at the start and simply use the normal Eraser and Clone Tool to do the job right up front - or ... 

simply grab the Selection Brush Tool and make a good selection of the Escalade and promote it to its own layer.  After all, if it takes a lot of effort then the effort may as well work easily the first time rather than having to do a lot of clean up.

In addition, any mistakes made with the Selection Brush Tool can be easily fixed.

Either one of thse alternate steps would, of course, bypass the Background Eraser entirely which, after using it for a few evenings, does not seem to be a bad thig.  I found the Background Eraser to be frustrating, unpredictable and really slow.  Maybe with more use my opinion would change but at this point ...

Maybe it will work better with a more challenging picture.

A Challenging Job


This is a more challenging job for the Background Eraser ...


background eraser challenge


One look at this image and you will immediately notice all of the little areas around the hair that need to be removed - and it would be a nightmare to complete with the normal selection tools.

After some initial experimentation these are the setting I ended up using with this picture ...
  1. Brush size was in the 80 to 120 pixel size.  The image was 1478 X 2000 pixels so a large brush worked well, especially around the hair.

  2. Pen Pressure (with my Intuos5 tablet) was set to change the Size with Pressure.  The Background Eraser is ideally used with a Pen and Tablet  especially in tight areas where a lot of precision is required.

  3. The Limits were set to Discontiguous (to allow the Background Eraser to jump over the stray bits of hair).

  4. The Tolerance setting was lowered to 6% and that was based on multiple practise sessions with the tool and this image.

  5. Before starting I created a new Levels Adjustment Layer and moved up the middle adjustmet to create a bit more contrast in the wispy bits of hair.  The Levels layer will be eliminated after the erasing is complete.

  6. After making the first pass on the background layer with the Background Eraser the Background layer became a normal layer (called Layer 0).


background eraser tool
backgtound eraser tool
After Adjusting Levels
Layers Palette


If there was a technique that is perfect for creating a new image for and watching the results then this is it

New Window For ...

Select View > New Window For > Your file name.... and then Window > Images > Tile to get the following screen (the Window on the right is zoomed in at 500% and the left is at 25%).  As I work on the right image whatever changes I make there are also seen on the left image.

The advantage is this - what is happening on the right image looks awful because of the little bits of hair that refuse to pay attention to what I want but in the big picture (on the left) it looks fine.  If you like to work at full screen then ignore this step - I tend to zoom in a lot.


background eraser tool new window for ...


Some of those stray bits of hair on the right certainly look awful but have no fear - we'll get them where we want them ...

NOTE:  if you're doing this with either a Wacom Intuos4 or Intuos5 professional pen tablet then give the Precision Mode setting a try.  What it does is scrunch the active area of the tablet into a small space so a lot of pen movement only goes a small distance on the image.  It is great for working in tiny, confined spaces.  It takes longer but the end results are better and those tiny little details ultimately determine how successfully the background erasing has been completed.


Moving Forward

Now the job is to move around the picture, specifically the hair and eliminate the background.  This can take quite a bit of time depending on how precise you want to be.  With my project it took me about 105 to 2.0 hours just to move around the hair.

When it seemed like it was done correctly I erased the rest of the background much more quickly - now its time to check my work.

The first thing I did was turn off the Levels Adjustment layer which returned the picture to its normal contrast. 

The second thing was to add a layer above Layer 0. fill it with a sold color (blue in my case) and drag it below layer 0  What this does is tell you just how effective all your work has been to this point and here's how effective mine was ...


background eraser blue layer

Well - yikes - that doesn't look particularly good, does it?  Zoomin in makes it look even worse but don't loose the faith - we can fix it up quite nicely.

If this is going on a light background then maybe nothing needs to be done.  If, howver, it will end  up on a background that has a strong contrast with the primary image then we need to get in there and clean up the hair.

Incidentally - things like hair and tree branches and bushes - they are probably the toughest to isolate.  To do it effectively requires patience and time.

Clean Up

background eraser detailThis is a screen shot of one part of the hair.

It's easy to see that the Background Eraser did well in some areas and not so well in in others.

To clean this up I used a combination of the Background Eraser, the normal Eraser and finally, the Burn Tool

In areas that were outside of the hair area I used the normal Eraser to get rid of anything that needed eliminating.

In the hair area I zoomed in, selected the Background Eraser and carefully selected the whitest pixels to eliminate.  The pen was set to get larger with pressure so I ended up putting the pen tip on a white pixel and then pressing the pen into the tablet to get as many of the lighter pixels as I could with one shot.

After working around the hair once again and getting it the best I could with the Background Eraser there was still some fringing which need repair.  This was a job best completed with the Burn tool which did an acceptable job.

The settings for the Burn Tool were ...
  • Size:  Small (and will depend on the size of the image).
  • Range:  Highlights.
  • Exposure:  60%.
The unsightly white part on the edges of her hair were darkened nicely with the Burn Tool but the hair still didn't look nice or natural.  In this case there were some areas that were still a bit too light.

This can be addressed with the brush tool, with black as the foreground color and the brush blend mode set to Overlay.

Maybe this is a situation where the Background Eraser just isn't up to the job.  It just seemed that the more that was done to separate the foreground and background the more was needed - a never ending project!

background eraser hairSelection Brush

Out of frustration I decided to pull out the Selection Brush Tool and make a quick selection of some of the hair.  It seemed to go quite well and if necessary I could have done the whole project over again with this selection tool.

Here is a screen capture of just a small part of the hair captured this way ....

You can easily see that this would work but it would also be a lot of work probably spanning a few sessions.


Another Point Of View

Gettin perfect hair strands and all of that is difficult but it may not be necessary depending on the new background for the picture - when the background is busy enough the angst of not having a perfect cut out can be avoided.

Here are three examples of the last image on different backgrounds.

In The Park


background eraser park


The less than perfect selection of her hair really doesn't matter with this particular background.

Tattoo


background eraser tat


The cut out was dragged onto another image, resized, rotated, text added and the Blend Mode of the cut out and text layers changed to Overlay - now we've got a nice little tat on this guys arm and the imperfect removal of the background from her hair doesn't really matter, does it?

From The Window


background eraser window


And now here's our friend watching from a window.

Summary

When I started writing this I figured it would be quick and to the point - wrong.  The Background Eraser sounds wonderful in theory but in practise it has proven to be a rather difficult tool to master.

From my point of view I will probably stick with the Seletion Brush Tool to make a precise selection, move it to a new layer and then deal with the background.

Users who have access to a later version of Photoshop will have even more options as there are some really great masking and extracting tools available.

There still is, however one more method to remove a background in Photoshop Elements - the Magic Extractor (at least in versions 9 and 10).  So far it seems to do the job and any clean up required with this method has all the tools included in the technique.

You may want to check it out here - Magic Eraser.




Page Links

Options
A Simple Example
A Challenging Job
  1. The Park
  2. Tattoo
  3. From The Window
Summary








Enjoy This Site?
Then why not use the button below, to add us to your favorite bookmarking service?



Return to top

Site build It!

Use the Contact Form to ask questions, provide feedback or comments.

Questions are good - so are comments - or requests!

Return to Background Removal from Background Eraser
Copyright© 2009-2012.