These are the settings used and no resizing has been done on the image just a few colour tweaks. I see there is a conversion from 16 bit to 8 bit too, which I don't understand? While I am very familiar with the arty side of Photoshop and ACR I am new to these technicalities so kindly explain. I do understand that there is a substantial drop in file size when converting to jpg and I understand the reasons why, but I just need to check that I am not inadvertently doing something to make that even worse. I am wanting to eventually resize this image to print as A2 size hence the concerns.
Working as intended. JPEG is a compressed, "lossy" format hence why the JPEG is much smaller as compared to your original RAW image, which is as "lossless" as it gets. (JPEG doesn't support 16-bit also unless someone can correct me on this.)
It goes without saying but don't get rid of your RAW images.
Thank you very much that was exactly what I wanted to know.