Unmerging complex shapes drawn with the pen tool

QUESTION:  Can merged shapes be undone after a file has been saved?  If so, how?

 

Background:  I use Photoshop to recreate and draw vector graphics based on renaissance and classical Asian art.  I have grown very comfortable with Photoshop after using it for many many years drawing images that have highly complex shapes ... literally consisting of tens of thousands of individual shapes.  I only use the pen tool adding and subtracting shapes to different layers and then filling them with colors and occassionally adding blending effects to layers.  I do not rasterize the final file choosing to save the master should future edits be necessary. A typical recreation can take up to 400 hours to build using my technique.

 

Unfortunately, I recently discovered a master file that had all of its layers merged into a single shape layer.  The image was a recreation of a woodcut of Albrect Durer ("Samson Rending a Lion").  I know merged shapes can be undone using the "undo" command.  While not a show stopper because the image is still a shape layer, I want to break the image back down into individual components such as Samson, the lion, background buildings and countryside, etc.

By @richard_0249

No, merged vector shapes in Photoshop cannot be directly separated or "undone" back into their individual component layers after the file has been saved, as the merging is a **destructive operation** that discards the original components' path data and clears the undo history. Since your image is still a single **vector shape layer**, you must manually restore the structure by using the **Path Selection Tool (A)** to select, copy, and paste distinct groups of subpaths (representing objects like Samson, the lion, etc.) from the single merged path onto **new shape layers**, and then manually re-applying the correct colors and styles to each new component.

It's not possible to go back once the file is saved and closed - unless you have an older backup.

You should really, really use Illustrator for this! Photoshop is not a vector editor. Photoshop's vector tools are intended as aids for selections and masking. They are not intended for output or archival storage.

In Illustrator, any path or shape can always be expanded into individual components. That's the basic building blocks of an Illustrator file, just as pixels are the basic building blocks of a Photoshop file.