Modified date change

[Sudasho]

How can I save pictures without change modified date?

A month ago I purchased Affinity photo and started to edit some pictures and saved as XXX.afphot and JPEG as well.

Then I noticed their modifyied date switched a day when I edit.

Let's say a picture taken last Dec25 and edit today as June 13 saved as JPEG then click "Get info" on Mac, and see modified date is the day not Last Dec25.

Please teach me how to fix the problem.

 

thank you 

[GarryP]

I don’t think this is something you can change as it is an operating system function - not something the Affinity software does - which is used for backups and other things.
If you want to keep the old date on the file then you should save a copy of the file instead of overwriting the original.

[Sudasho]

Hi GarryP

Thank you for your advise. Let me give one more question 

Can you tell me how do you organize edit pictures by Affinity photo by modified date?

[Wosven]

Usually you've got 2 dates per file: the creation date and the modification date. Only thé second should update, unless you save the file in a new format.

[Sudasho]

Hi Wosven 

thank you for your comment

If you don't mind can you tell me your way to save a picture without update modification date?

It will be huge help and appreciation.

Thank you.

[Wosven]

That's not possible, since it's how it's working.

You just need to display and look at the creation date instead.

[v_kyr]

5 hours ago, Sudasho said:

Then I noticed their modifyied date switched a day when I edit.

Let's say a picture taken last Dec25 and edit today as June 13 saved as JPEG then click "Get info" on Mac, and see modified date is the day not Last Dec25.

Please teach me how to fix the problem.

From a terminal (Terminal.app or iTerm etc.) you can change a files “date modified” attribute afterwards this way ...

Quote

touch -mt YYYYMMDDhhmm filename.ext

...and thus...

touch -mt 201912250000 yourfile.jpg

... in order to change both, the “date modified” and “date created” attributes, try instead ...

Quote

touch -t YYYYMMDDhhmm filename.ext

...aka...

touch -t 201912250000 yourfile.jpg

 

[R C-R]

4 hours ago, Sudasho said:

If you don't mind can you tell me your way to save a picture without update modification date?

Like the creation & last opened dates the modification date is metadata stored in the file system of the Mac. (It is not stored anywhere in the file itself.)

It is possible to change those metadata date-related items using advanced techniques but it is not advisable to do so because it can cause a number of problems with backups, version control, & other OS level things that rely on their correctness to work as they should..

[Pšenda]

1 hour ago, R C-R said:

It is not stored anywhere in the file itself

EXIF (JPEG file) has this information. Some editing tools (such as ExifTool) can modify these dates, or they can set file dates accordingly.

[R C-R]

2 hours ago, Pšenda said:

EXIF (JPEG file) has this information. Some editing tools (such as ExifTool) can modify these dates, or they can set file dates accordingly.

True, but the EXIF metadata (optionally) stored in the file itself & the file system metadata stored in the Mac's file system are two different & completely independent things. So changing the date-related EXIF metadata in the file has no effect on the date-related metadata stored in the file system & visa versa.

[Sudasho]

Wolven thank you, So I have to accept modified date is the day when i edit. 

[Sudasho]

V-kry I will try your way. Thank you

 

[Sudasho]

R C-R Hummm so you do not recommend touch EXIF date for modification or creation date.

Thank you

 

[Sudasho]

Psenda I concern to DL EXIF TOOL thank you.

[R C-R]

4 hours ago, Sudasho said:

R C-R Hummm so you do not recommend touch EXIF date for modification or creation date

No! It is the file system metadata that should not be changed. It is perfectly OK to change the EXIF metadata embedded in the file if there is any need for that. In fact, Apple's Photos app provides a way to change some of the EXIF metadata, as do many other apps.

In Finder & 'Get Info' windows, the creation, modification, & other dates you see are file system attributes managed by the macOS. Unlike EXIF metadata, they are not part of the file itself.

[v_kyr]

35 minutes ago, R C-R said:

No! It is the file system metadata that should not be changed.

That's nonsense, especially the above said, since in the context of programming project related tasks and build processes it's deadly needed and common usage. Since an updated access or modification date can be important for a variety of other programs such as a VCS, backup utilities, or the make command-line interface programming utility. Typically these types of programs are only concerned with files which have been created or modified after the program was last run. So there is a good reason why every Unix and Windows system as default usually comes along with a build-in touch command.

 

[R C-R]

53 minutes ago, v_kyr said:

That's nonsense, especially the above said, since in the context of programming project related tasks and build processes it's deadly needed and common usage.

Please do not take what I said out of context. I am not talking about programming an app, a CLI utility, or any build-related process. That is not what is being discussed here.

Among other things, it is well known that changing the creation or modified date of user document files can play havoc with Time Machine backups & with clone utilities like SuperDuper!

[v_kyr]

12 minutes ago, R C-R said:

Please do not take what I said out of context. I am not talking about programming an app, a CLI utility, or any build-related process.

...because it can cause a number of problems with backups, version control, & other OS level things...

All that is part of your above sketched context, namely the common OS level things, aka the timestamps (i.e., dates and times of the most recent access and modification) on existing files and directories in a file system . Creation & update of the date and time attributes of files/dirs on file systems has always been a common task since the early beginnings of Unix systems. - What you name now is solely due to Apple specific idiosyncrasies and only related to TimeMachine (and tools which have to deal with that), where you have to go the Apple specific way then with tmutil.

[Sudasho]

R C-R thank you for your warning. I will not touch and I use Photo app to organize my pictures afterward.

 

 

[Sudasho]

v_kyr I am not that far about computer system, so I will use Photo app on Mac,  thank you so much.

 

[R C-R]

8 hours ago, v_kyr said:

Creation & update of the date and time attributes of files/dirs on file systems has always been a common task since the early beginnings of Unix systems. - What you name now is solely due to Apple specific idiosyncrasies and only related to TimeMachine (and tools which have to deal with that), where you have to go the Apple specific way then with tmutil.

I do not think it serves any useful purpose to comment on the early days of Unix systems here but I must point out that the macOS is not simply a 'pure' Unix OS so we do have to consider its "idiosyncrasies," including for anything related to making manual changes in the file system timestamps.

[v_kyr]

Those are pretty essentiells of any OS filesystem, aka making possibly manual changes to files time attributes, same as changing access rights etc., thus that's all nothing special here. And macOS behaves overall like a common BSD Unix system here in regard to these things.  Thus all the common Unix filesystem commands should work, especially for any certified Unix system.

[markw]

If I want to change dates on standard image formats like jpeg, png etc… after editing them in AP,  I use 'XnConvert' or 'Photos Exif Editor'. A word of warning though, never use either of these apps to change meta data on images contained in Apple Photo’s ‘Photos Library’. They will mess it up and stop Photos from working properly!
So if it’s an image that’s in Apple Photos who's date you want to change then always use Apple Photos built in ‘Adjust Date & Time’ function.

[R C-R]

2 minutes ago, v_kyr said:

Those are pretty essentiells of any OS filesystem, aka making possibly manual changes to files time attributes, same as changing access rights etc., thus that's all nothing special here.

In what situation(s) would you consider it essential to make any manual changes to file system date/time attributes?

When would it be something typical Mac users would need to do, & for what purpose? Same question for changing access rights.

9 minutes ago, v_kyr said:

And macOS behaves overall like a common BSD Unix system here in regard to these things.  Thus all the common Unix filesystem commands should work, especially for any certified Unix system.

While overall that might be true, it does not mean that just because most common UNIX command should work that it is safe to use them without knowing exactly what they do or how they could affect normal system or app operations.

[v_kyr]

14 minutes ago, R C-R said:

In what situation(s) would you consider it essential to make any manual changes to file system date/time attributes?

Distribute and release versions of a projects stand, update github, Bitbucket etc. repositories with local code, rebuilding stuff with make,  fixing wrong file and directory settings from your cams transfer, the cloud or external drive, ... etc. There are many different workflows where the consideration of files with older timestamps, which are otherwise ignored, are commonly needed.

25 minutes ago, R C-R said:

When would it be something typical Mac users would need to do, & for what purpose? Same question for changing access rights.

Team work, shared access, prevention of overwrite of important things, giving access to groups and other individuals, make scripts executable, setup system services ... and so on. - Also very important if you have to setup and administrate your own local webserver, database, CMS, VCS, VPN ... and certain other services. - Why do you think there do exist serveral user roles and there is a root aka superuser, plain or guest users etc.? - So what would you do if you couldn't do that stuff at all?