We have found 3 software records in our database eligible for .pdn to .psd file format conversion.
Both .pdn and .psd files are graphics files, but come from a very specific software, Paint.Net and Adobe Photoshop respectively.
The obvious tool to handle .pdn files is Paint.Net, but it does not support saving to Photoshop's PSD format and Photoshop does not support import of Paint.NET's PDN format, which means you either have to use some exchange format to transfer the graphics or find some graphics editor that supports both of these formats.
Using exchange format seems to be the get go approach how to achieve pdn to psd conversion.
Updated: August 31, 2023
PDN
Files with pdn extension can be usually found as raster graphics files saved in Paint.NET graphics editing tool.
PSD
A psd file extension is traditionally associated with default graphic format of Adobe Photoshop. Adobe psd graphics file is pixel based graphics file format. However some graphic elements can be stored in vector graphics. In default psd graphics file contains layers with masks, color spaces, ICC profiles, transparency, text, alpha channels and spot colors, clipping paths, and duotone settings.