Error in docs about "file creation date"

[Wilhelm Sanke]

I am not intending to continue this thread endlessly, but I think the 
last contributions and questions of Ian Wood and Jacqueline deserve 
another response.

I had written:

> When a photo is taken, it gets a modification date at the same time, 
> although it is - as it were - only modified out of non-existence.
> The creation date is generated when the image arrives on the computer, 
> and a new creation date is generated each time the image is saved or 
> copied. Simply "moving" an image to another folder does *not* change 
> the creation date.


This holds for Windows and Ian had pointed out that the situation might 
be different for MacOS. I had responded that for various reasons I am in 
the habit of *copying" the files from the memory card to the computer. 
For that purpose I use an USB card reader.
I have now tested simply "moving" the files from the memory card, and in 
this case the creation dates are indeed preserved.
But copying/pasting of files to another folder or volume changes the 
creation date, as does "save as" under a different name, but in all 
these cases the EXIF-creation date - which is not taken into account by 
the detailed files function - remains unchanged.

Jacqueline had commented:

> I know the Mac doesn't change creation
> dates when just saving a file, and I haven't noticed it on XP either --
> though I admit I do very little editing on that OS. Most of my image
> editors are on the Mac.

What about "saved as"?-

As I don't have a card reader for the Mac (or could not get it 
configured for lack of a drivers disk) today I imported images directly 
from the camera via USB,

once transferring the images directly from the camera by "dragging" the 
files from the memory card folder to a folder on the Mac desktop.
The detailed files show the "phantastic" date of "Jan 18, 2038" as the 
creation date, whereas the modification date is correct.
When I open the folder in "column" view and click on a file name, I get 
the information that the creation date is "empty".
However, the correct EXIF creation date is still connected with the file 
and can be inspected with EXIF tools like Alex's "libEXIF" stack.

Then I used "iPhoto" to *import" the same files into the iPhoto Library: 
Now the detailed files show May 22 (today) both for the creation and the 
modification date.
The information directly from the library folder in "column" view is the 
same. Apparently the iPhoto import function works in the same way I copy 
the images from the memory card to the computer on WindowsXP.

Jaqueline again:

> >> But this does not explain the "phantastic" date of "Jan 18, 2038" 
> which
> >> I got for the creation date - item four of the detailed files - when I
> >> transferred files to my Powerbook with an USB stick.--
>
> Oops, forgot to address this point. It would be interesting to see what
> the creation date is on the USB stick, before the transfer. I wonder if
> something about USB is munging the date somehow when the file is copied
> (I think you suspected this too at some point.) After you've copied the
> file to the hard drive, does the creation date listed in the properties
> dialog on XP match the unusual year as well?


The creation date on the USB stick - after having copied the images 
there from my Windows computer and inspecting them there still from 
WindowsXP - show the "actualized" creation dates because they have been 
copied at the same date.
But read from the Mac with the detailed files, we get "Jan 18, 2038", 
and "empty" for the creation date when looking at the file information 
in the Mac folder.
The EXIF data are intact in this case, too, which read May 5th as the 
correct creation date in this case.

I tried three other USB sticks and always get the same phantastic 
creation date. When I connect an old Mac harddisk via USB with my 
Powerbook, the phantastic date does *not* appear.--

I repeat my recommendation to add the ability to read EXIF data with the 
detailed files function:
EXIFdata seem to be really reliable data, survive most transfer 
procedures, and spare you the trouble to remember in which way you have 
transferred image files from one volume or folder to another or which 
special photo tool you used to transfer the images. And they survive 
even when the image file is "saved as" under a different name. They will 
disappear only when you make major changes to the image contents - like 
manipulating the imagedata.

Regards,
Wilhelm Sanke

<http://www.sanke.org/MetaMedia>