How do you layer transparency?

[nabsltd]

The title isn't good, but I really don't know how to describe what I want to do.

 

Basically, I have an object (text letters) that I want to create an "engraved" effect, using a separated drop shadow.  Here's a sample image:  This was created by having 3 layers:

the blue text: 

a small gray (RGB 200,200,200) shadow (using the "Object Shadow" plugin) with Blending mode "Additive": 

and a larger gray shadow: 

This looks good on a white background, but I want the effect to work regardless of the background, so that the pixels that overlap between the mask and the shadow become transparent.  In other words, what's green in this picture should have no color, just alpha information: 

 

How can I do this?

[BoltBait]

Type your text on a transparent layer, then try this plugin on that layer:

DisconnectedObjectShadow.zip

 

EDIT: This is just a quick hack, so it could probably be improved.  Feedback?

 

[nabsltd]

4 hours ago, BoltBait said:

EDIT: This is just a quick hack, so it could probably be improved.  Feedback?

 

Add in the ability to move the shadow and keep shadow only (I like to keep shadows on a separate layer so I can go back and change later), and it definitely solves my problem.  

 

Perhaps it could just be merged into your original Object Shadow as an optional parameter for how fat the "disconnect" gap is.  I like the fact that you have added finer control for the movement.  I ran into some issues where a single step on the current one got rounded down, and the next step was too much.

 

It still doesn't answer my more general question of how to do the masking, and I'd really like to know the general solution.

[IRON67]

5 hours ago, nabsltd said:

It still doesn't answer my more general question of how to do the masking, and I'd really like to know the general solution.

 

If you want a shadow layer that REACT different on different backgrounds, then you have to make it manually because a layer can't know, what you want and what you like. Use different blend modes.

[nabsltd]

OK, I've figured out how to do this easily.

 

1. Start with the object layer.

2. Duplicate it twice.

3. Create the dark shadow on the second duplicate using BoltBait's Object Shadow.

4. Create a smaller white shadow on the first duplicate.  Now, the picture looks right, how a disconnected shadow would appear on a white background.

5. Duplicate each of the shadow layers, and then merge them together, with white on top of dark.

6. Select all on this combined shadow layer, and copy to clipboard.

7. Move to the dark shadow layer, and use the Paste Alpha plugin with alpha source set to "Clipboard shades of gray", "Invert Calculation" checked, and paste method of "Minimum of alpha and clipboard alpha".

8. Delete the white shadow layer and the combined shadow layer.

9. Now, the disconnected shadow is separated by transparency, instead of white.