Designed to work on flat, butt-fitting layers, the Despeckle Filter removes stray pixels, or groups of pixels which are surrounded by another colour, and place them on other, more appropriate layers. It is most often used to clean up separations and remove areas of noise on separated layers.
Instructions
- Open the Filter Browser, and add a new filter set using the small + icon located in the middle of the browser. This will create a new ‘untitled’ filter set for you. This will appear in the top section of the Filter Browser. If you already have filter sets created, clicking the + button will duplicate the selected filter set.
- Select Despeckle from the list of available filters in the lower section of the Filter Browser
- Double click on the name of the new filter set in the top section of the browser, and name it appropriately
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Edit the variables to achieve the result you needIn the example below the filter is being used to reduce all tones
Speckle size - the software looks at groups of pixels up to and including the set amount. For example, if you type 20 in the window, the software will look for groups of 20 pixels or less and will change them to the closest, or surrounding colour. Either enter the value needed or use the slider to preview and try out different amounts. The maximum speckle size you can use is 300.
Preserve Diagonals - switching off preserve diagonals makes the despeckle effect more coarse. With preserve diagonals switched on, line detail will remain the same and pixels on the edge of motifs will be kept in tact.
In the snapshot below, the original data is on the left, and the filtered data is on the right.
Applying the filter
There are several ways to apply a filter:
- Click Apply - this will apply the filter to the active layer(s), and within a selection if there is one present in your file
- Click Make Layer - this will make a new layer in your file containing the filtered effect, leaving the original layer untouched
- Apply the filter using the Brush Tool - when you have finished building your filter set, simply close the Filter Browser. Then, open the Brushes Library, and select the filter you have just made from the drop down menu shown in the image below. You can now paint with your filter.
Note: The default setting for the Brush Tool is ‘Brush”, located at the top of this drop down menu. To prevent you from becoming confused between the default setting and a filter setting, do not name any filters ‘Brush’. When you have finished painting with your filter, set the drop down menu back to the Brush setting, otherwise the Brush Tool may not behave as you would expect later on.
Note: This filter does not work on images.
Applying the filter over a repeat join
Some of the filters do not work correctly across repeat joins when used in the normal way. However, the Despeckle Filter, does. All you need to do is use the Repeat Window to put your design into a 2 x 2 repeat prior to applying the filter.
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