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Files with the extension .gp4 are known as "GTX Group IV format /CALS picture".

This file format was added to our database by a visitor to this site, but no additional information was provided.

We have yet to investigate the gp4 file extension any further, or there was simply not enough information available at the time to report accurately on the format. If you know how to open gp4 files or even how to convert or edit them, please use the form below.

However, it is possible that other file formats exist which also use the gp4 extension, so please let us know if you do not think the gp4 extension matches the file format you are looking for.