I hope I can serve you ... create a folder where you want, I recommend the desktop so you can visualize it quickly
then open your Photoshop file the PSD with your 100 scanned layers
Then you export all the layers as a separate file in the folder you created previously using File / Sequence Command / Export Layers to file.
After having all the images in a separate folder, you will create an action in photoshop. Window / Actions or [F9]
and you give the option to record, you will do everything you are going to do with a single image, so that later it is done by batch before you have to finish the recording and close all the images.
the entire combination will be processed.
This is done without problems with photoshop 6.0
I hope it serves you ...
Greetings ....