Stopping an action when the bottom-most layer is reached

[lena_segan]

Hello all, 

I'm looking to get assistance on creating an action in Ps to automatically remove background from images, but the problem I'm running into is when I stack all those images as layers, and run the action (remove background quick action, select backward layer, and then loop back to remove background, and so on), I have no clue how to make it stop after it's selected the bottom most layer in the stack, it just switches to the topmost one and continues going.

In essence I'm making GIF animations from green screen footage, and needed a way to automate it somehow, because removing the BG on 50+ stacked GIF layers is a bit tedious.

Any assistance with this would be greatly appreciated.

[Chuck Uebele]

I'm a bit confused as to what you're doing. As far as I know, an action can't loop, so are you using a script? Do you just want to delete the bottom layer? You can just select the bottom layer with the shortcut alt/opt-,

[JJMack · Accepted solution]

In an action you can start at the top or buttom of visible layer  and process visible layers relative the the starting position. However there is no action conditional you can user to know when to stop. You can come close if yout start at the top and the is a  visible background layer but then you can not remove the background in a photoshop background layer and many documents do not have a background layer

[lena_segan]

JJMack, you are a saviour! I wasn't aware that you could set conditional actions, so what I did was stacked all my to-be-GIF layers, created a locked layer at the very bottom of the stack, just a dummy one, and added that conditional action for the loop to trigger a stop action if it detects a locked layer. Worked like a charm! Thank you

[lena_segan]

In essence I'm making GIF animations from green screen footage, and needed a way to automate it somehow, because removing the BG on 50+ stacked GIF layers is a bit tedious.

[Stephen_A_Marsh]

Please post a screenshot of the action will all steps expanded.

[lena_segan]

Here's what I've got after adding the conditional action JJ Mack mentioned, see above.

It works well like this now.

[Chuck Uebele]

A script can easily detect the last layer:

var doc = activeDocument;
if(doc.activeLayer == doc.layers[doc.layers.length-1]){alert('this is the last layer')}

[Stephen_A_Marsh]

/* 
Lena wrote:
In essence I'm making GIF animations from green screen footage, and needed a way to automate it somehow, because removing the BG on 50+ stacked GIF layers is a bit tedious.
*/

FYI, there are numerous scripts that will iterate/loop an action over all layers in a file.

[lena_segan]

I was good on how to create a loop, may not have worded it well, but I was trying to add a way to stop it. Sorry 'bout the confusion, I'm a bit new to all this.

[Stephen_A_Marsh]

Actions can have problems doing this as you found, a script doesn't, it knows when to stop without having to be explicictly told to do so.