maintaining corrected photo dates
I currently have all my photos in iCloud Photos & locally in my Photos library on my MacBook. I was looking into other options for my cloud backup in case I decide not to buy another iPhone or Mac computer.
Many years ago, I encountered some problems copying photos between old phones & computers, resulting in many photos having incorrect dates attached to them. (This was pre-cloud backup days, so the local copy was the only copy and had to be copied & backed up manually). I spent a long time painstakingly correcting the dates on hundreds, maybe even thousands of photos, but I did it. Everything is correct in the Apple Photos world.
However, it seems the dates I changed are only some kind of reference date for the Photos program, and do not actually change the metadata on the picture. So, if these photos are exported, or uploaded to another cloud like Google, the date reverts back to that incorrect date, making a huge mess of my photos all over again.
Has anyone else solved this issue when crossing between platforms? Is there an easy way to make the EXIF data match the date I assigned to the photo?
Thanks for any help you can offer.
MacBook Pro 13″, OS X 10.11