Please gener7 do not answer this!
I have posted this looking for help and have gotten some really sketchy answers. I am hoping to find someone who actually know this and can help.
I have in the past opened a file with the dimensions of 5184X3456 @72ppi. This metafata would show in bridge and then when file size was checked in Photoshop. Now when I open a file, any file, it will show in PS for image size 5184X3456 but at 200ppi. I am guessing this is a preference that has somehow gotten changed but I do not know where. The only update I have done is a recent update to lightroom.
I am using Photoshop CS6 and Adobe Bridge for my work flow. When I view the metadata in Bridge it shows a file size of 5184X3456 @ 72ppi. When I open that same image in CS6 and check the image size without altering it the size is 5184X3456 @ 200ppi. What preference has been changed to change the ppi size? This is a new situation for me as I have used PS for many years without this problem. I am using Windows 10 and Photoshop CS6.
Is the file opened through ACR? It has its own settings for resolution, and this is how the file will open into Photoshop, regardless of any previous ppi setting reported by Bridge.
And just as general background, apologies if you already know this: Pixels per inch is metadata, it's not a property of the file. It can be arbitrarily assigned without affecting image data.
A file without any resolution metadata at all, will open into Photoshop at 72 ppi. This is because Photoshop has to assign something, and the default is just set at 72. Other applications may have other defaults. In Bridge missing resolution metadata will just leave that field blank.