we look at the first in a series on Photoshop Actions.  Steve Everist of King County Sheriff's Office has used this feature of Adobe Photoshop extensively, and will relate some of that knowledge and how it applies to latent print examination over several Details in the coming months.

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Latent Print Photoshop Action Series Part 1: Creating Actions
by Steve Everist, CLPE
King County Sheriff's Office
Seattle, WA

Actions can be a useful tool for creating shortcuts for common procedures when working with digital images in Adobe Photoshop.  Essentially an action is a recording of a group of steps that can be played back for any image. 

In this example, I will create a very basic, simple action to use with Ninhydrin prints.  I will be converting a scanned Ninhydrin print from the RGB color space into the CMYK color space.  Then I will select the Magenta channel.  After selecting the Magenta channel, I will convert the image into Grayscale.

Before I start recording my actions, I will clean up the default actions that come with Adobe Photoshop.  This step is not necessary, but by doing so it will clean out the Actions Palette when in Button Mode.  To do this, I will need to take the Actions Palette out of Button Mode from the Actions Palette Options menu.  This can be accessed by clicking on the arrowhead in the upper right hand corner of the Actions Palette.  Since Button Mode is checked, I will click on the words “Button Mode” to uncheck it.

Now I will delete the default actions.  In the Actions Palette, I will go to Default Actions.atn, grab the set by clicking and holding it, then drag it down to the Delete icon shaped like a garbage can.

Next I will create a new set to put my actions into.  I will go back to the arrowhead in the upper right corner of the Actions Palette and select the option “New Set.”

The New Set window will pop up.

I will type in the name “Forensic Actions” for the set, then click “OK.”

The Forensic Actions set will now appear in the Actions Palette.

Now that I’ve created my Forensic Actions set, I can begin the process of recording my action.  First I open the image that I will be working with.  For creating the action, I can use any image, but to see the steps as I progress, it is best to use an image similar to one where I would find the particular action effective.

In order to record an action, the Actions Palette must not be in Button Mode.  Since I already took it out of Button Mode earlier, I can now create my new action.

On the Actions Palette, I will click on the “Create new action” icon, which looks like a piece of paper with a folded corner.

The New Action box will pop up. 

Here I can give my action a name, specify the set of actions that I would like the action put into, assign a function key, and choose a color for the button for this action.  I have chosen to call this action “Nin – CMYK – Magenta Channel.”  This describes what this action is used for and what steps it consists of.  I put it into the “Forensic Actions” set I created earlier and I chose violet for the button color.  Once the action has been set up, I will click the “Record” button to start recording the steps for my action.

The first step for this action is to convert from RGB to CMYK color.  This is done from Image – Mode – CMYK color.

Now I will click on the Channels Palette.  There are five different channels: CMYK, Cyan, Magenta, Yellow, and Black.

Next I select the Magenta channel, by clicking on it, which will darken the pixels that are in the Magenta channel, while lightening the pixels in the other channels.

Although the image will appear to be in grayscale at this point, it is still in CMYK color.  I will need to convert it to Grayscale.  This is done from Image – Mode – Grayscale.

The Discard other channels window will pop up.  I select OK to discard all of the channels except for the selected Magenta channel, and convert the image to grayscale.

Now I have finished recording the steps for this action.  I will click on the “Stop playing/recording” icon at the bottom of the Actions Palette.  This icon is shaped like a square.

I have now successfully created an action to use on prints developed with Ninhydrin and can return to Button Mode.

Looking at the Actions Palette, my new action will be a button that I can click at any time to take the active image through the steps used in recording this action.

Although this won’t be the ideal process for every print developed with Ninhydrin, it can be used as a good starting point.  From here other adjustments, such as levels, can be performed to further enhance the image. 

Since this action will select any pixels in the magenta channel, Ninhydrin prints on backgrounds with magentas in them may not provide the needed contrast between the print and the background.  In this case other steps may be best suited for isolating the print from the background.

The same techniques shown here can be used to create a variety of actions for tasks that you find yourself doing repetitively.  These include opening, converting, and saving files as well as basic image enhancements.  Also remember that all of the steps you take while recording your own actions will be saved to that action.  So if you make mistakes while recording the action and go back, the action won’t step back along with you.  Instead it will create a new step of selecting a previous state.  You also may not want to record steps like crops, levels adjustments, and other procedures that will be specific to one image but may not apply to another image. 

Actions can be useful time-savers for a variety of tasks that you find yourself repeating.  With a little practice, you can create your own actions to help reduce time and effort.  You can also save your actions to a file and share them with others.  To save a set of actions:

1. Select a set.

2. Choose Save Actions from the Actions palette menu.

3. Type a name for the set, choose a location, and click save.

You can save the set anywhere. However, if you place the file in the Presets/Photoshop Actions folder inside the Photoshop program folder, the set will appear at the bottom of the Actions palette menu after you restart the application.

For more information regarding actions, go to the Photoshop Help window and do a search for actions.

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