Filter Introduction

Filters are an amazingly easy way to change your image in original and unique ways.  What are filters?  Filters are effects that can be applied to single layers, group layers, shape layers, and selections.  With a little bit of fiddling, filters can create things you never even imagined! 

To get started, select the layer you wish to work with in the layers list. This example will use an image of a sunflower. 

Bring up the filter window by either picking a filter from the Filter menu item or clicking the 'fx' button in the lower left hand corner of the inspector palette.  You can also use keyboard shortcut ⇧⌘F.  

In the example below to the right, Filter ▸ Tile Effect ▸ Kaleidoscope was chosen.  Acorn shows the effect the filter has on your image immediately.

Once you have chosen a filter, you will see 'fx' on the right-hand side of the layer in the layers list.  

If you need to change the values of the filter later, just return to the filters window by double clicking the 'fx'.  If you wish to make a filter effect permanent, select 'Flatten' in the filters window.  Once you have flattened a filter, you will no longer have the ability to modify it and the 'fx' will disappear from that layer in the layers list.  

The power of the filter window comes in stacking filters together to make workflows.  In this image, the 'hue adjust' filter has been added on top of the kaleidoscope filter.  Play around with adding, deleting, and moving filters around in your filters window to create endless effects! 

Filter Basics

Adding Filters:   Once you have selected a filter, you can add more filters to the same layer by clicking on the '+' button in the lower left hand corner of the filter window.  

Removing Filters: To remove any filter, click on the 'X' in the upper right hand corner of that filter's parameters. 

Moving Filters:  To move a filter up or down in the filters list, just drag and drop it to the location you desire.

Search Filters:  The first time you click the 'fx' button, the filter search field will appear.  Once you've added a filter, you can click the '+' button again to access filter search.

Copying Filters: To copy a filter, click on the cogwheel in the lower lefthand side of the filter window and choose 'Copy Filter'.  You can then select a different layer in your layers list and paste the filter in (⌘V or Edit ▸ Paste). 

Committing Filters: To make the filter effect permanent on your layer, click the 'Flatten' button at the bottom righthand side of the filter window.  You can also choose Layer ▸ Flatten Layer Filters.  You can leave your filter effects open to further modification in the future if you don't click 'Flatten'.  

Visibility:  Click on the eye next to the filter in the filter window to toggle its visibility.  If you wish to toggle the visibility of all the filters in your list you can hold down the option key while clicking the 'fx' in the layers list.  

Enable/Disable Layer Filters: Control click (or right click) on the layer in the layers list to bring up a contextual menu with these options.  You can also navigate to Layer ▸ Enable/Disable Layer Filter.

Filter Description:  If you select a filter in the filters window, a brief description will appear at the bottom of the window.

Last Filter:  The Filter ▸ Last Filter menu item is enabled when when you hit the "Flatten" button in the filter window. You can then use keyboard shortcut Command-F to add the last filter chain to another layer.

Adjusting Filter Parameters  

Many filters have values you can adjust in the filters window through sliders or number entry.  Some filters contain options that can be manipulated directly on your image such as the 'Center' and 'Radius' options for the radial gradient filter.  To toggle the visibility of 'on image' filter controls, click the button to the right of the cogwheel in the lower left hand corner of the filter window.

You can also see how this works in the filters video tutorial: Filters Basics.  

What are Quartz Compositions?

Quartz Compositions are filters created using Quartz Composer, which is a visual programming language and IDE provided by Apple.  Anyone can create their own compositions, which can then be downloaded and installed.

Acorn will list your Quartz Composition filters under the Filter ▸ Quartz Compositions menu.

To install a Quartz Composition, you can either place the composition file (which will have a file extension of "qtz") into your ~/Library/Compositions folder or you can drag and drop the file into Acorn.  If Acorn is running, you will need to restart Acorn for your filter to show up.

Using the Compositions

Most compositions require some sort of input, such as the Film Stock composition to the right.  Other compositions, such as "Color Pencil" do not require input.

When a composition requires a location for the filter, such as the Kaleidoscope filter shown above, Acorn will provide a thumbnail of the image on the left side of the composition parameter window.  You can then click and drag to adjust the x/y coordinates of the filter location.

Adjusting the Time Parameter

Some compositions, such as "Swing", provide a Time parameter.  Adjusting the time value will tell the composition where in its virtual timeline it should hold stationary.  In the Swing example to the right, adjusting the time will place the two selected images at different locations from foreground to background.  The time is currently set to .4, which places the selected source image at 60% along its "swing", and the selected destination image to 40%.