EXIF/ IPTC removal

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davidh
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Joined: June 9th, 2009, 2:16 am

EXIF/ IPTC removal

Post by davidh »

Sometimes I need to remove EXIF/IPTC data such as date, exposure info, camera manufacturer and model, but I have not found a way to do it in PWP.
I used a few times a simple application called Stripper, which does it with a single click, at least from JPEGs and PNGs .
Anyway , since it is possible to add some user EXIF/IPTC data using PWP Image Properties window, why is it not possible to remove those mentioned above from the same window? Or is it more complicated than it seems? Thanks.

David

ksinkel
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Re: EXIF/ IPTC removal

Post by ksinkel »

When you save a file as jpeg, you have the option to include comments. If you uncheck the option, the saved file will be stripped of comments. This option is also available in workflow. This allows you to save a separate copy for use on the web, for instance.

This is a sticky setting, so make sure to check it again, of you generally want to preserve comments.

Kiril
Kiril Sinkel
Digital Light & Color

davidh
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Re: EXIF/ IPTC removal

Post by davidh »

Kiril, thank you for a very fast reaction. I wonder how I could have overlooked this option.
One more question. There are two possibilities to include or exclude comments: one is in the common Save dialog and another is in the PWP Save File gray pop-up window where it is possible to change the settings and resave using the Save Again button. Does this Save Again step only edit the metadata or is it eqal to opening the image and resaving with the inevitable degradation of the jpeg image? Thanks.

David

ksinkel
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Re: EXIF/ IPTC removal

Post by ksinkel »

The operation is the same in both cases -- Save and Save As both recompress the image. However unless you are using a very low jpeg quality setting, the effect of this is minimal. You can determine the impact of this recompression by comparing the before and after images using Special Effects/Difference or just looking at images side by side and judging the difference for yourself.

Kiril
Kiril Sinkel
Digital Light & Color

davidh
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Re: EXIF/ IPTC removal

Post by davidh »

Saving an image as jpeg always compresses and more or less degrades the image, that is clear. Let me put it this way. When I save a tif image with Show statistics unchecked I get a compressed jpeg image. But when I save it with Show statistics checked, I can then not only specify in the File Save (JPEG) dialog what information I want to include but also change the Color Sampling and Quality. My question is, what happens after I change someting and click the Save Again button? Is the jpeg image already saved by the Save dialog saved again at the background and thus recompressed or is the original tif image still kept in memory and saved only now as ipeg and compressed only once? Thanks.

David

ksinkel
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Re: EXIF/ IPTC removal

Post by ksinkel »

Formats like Tiff and Jpeg only apply to image when they are stored as files. Once an image is read into picture Window it is represented in memory in uncompressed form. Thus if you save that image twice, say once with and once without comments, each save is made directly from the memory representation. Thus each save would only be compressed once and there would be no accumulation of artifacts. In other words, saving an image does not affect its memory representation -- compression is applied to the image in the file not to its format in memory.

Kiril
Kiril Sinkel
Digital Light & Color

ksinkel
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Re: EXIF/ IPTC removal

Post by ksinkel »

I glossed over your point on Show Statistics in the JPEG options portion of the File Save dialog.

Show Statistics refers to the pop-up that is displayed after the file is saved. This popup reports the actual size of the saved file after compression. If you need more compression (or have more room and therefore can go for more quality) the dialog lets you change Jpeg parameters and save the file again until you get the level of compression you want. Unchecking Show Statistics simply suppresses this dialog.

Note that the jpeg quality, pixel depth, and include comments/profile parameters are available on the main File Save dialog regardless of whether Show Statistics is checked or not.

Kiril
Kiril Sinkel
Digital Light & Color

davidh
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Joined: June 9th, 2009, 2:16 am

Re: EXIF/ IPTC removal

Post by davidh »

Kiril, thanks for the explanation. My post is all about an attempt to keep in the jpeg image Statistics, Profile and User comments and get rid of the rest of metadata such as camera model exposure settings etc.

Checking Profile and Comments checkboxes in the Save Image dialog includes also all the unwanted information. Unchecking them removes also both User Comments and Profile.
The electronic manual does not diferentiate various parts of the metadata, so perhaps separating User Comments, Profile and
Statistics metadata from the rest is not possible using the options of the Save Image dialog.

Fortunately it can be achieved by using Copy and Paste which reliably removes all information except Profile and Statistics from the new copy of the image. Only User comments have to be reentered manually.

Anyway, while I was trying to separate the metadata I have discovered a kind of relation between the Save Image and the Save File (JPEG) dialogs that I do not quite understand and wonder if it is intended. Let me describe it.

I used a tif image with all the metadata including some user comments.
With the Statistics option checked - to bring about the Save File (JPEG) window - in the Save Image dialog:

A.
1.check Profile and Comments checkboxes in the Save Image dialog then Save image
2.in the Save File (JPEG) window select the "Neither Profile nor Comments" option then click Save Again.
3.look into the image properties: the Profile and Comments info is still there
4.reopen the Save Image dialog: the Profile and Comments checkboxes will be red and unchecked - set according to "Neither Profile nor Comments" - next saving of an image will remove them.

B. the opposite scenario
1.uncheck Profile and Comments checkboxes in the Save Image dialog then Save image
2.in the Save File (JPEG) window select the "Profile & Comments" option then click Save Again.
3.look into the image properties: the Profile and Comments info are missing
4.reopen the Save Image dialog: the Profile and Comments checkboxes will be checked - set according to "Profile & Comments" - next saving of an image will include them

It looks as if the Save Again button in the Save File (JPEG) window does not change the metadata nor overwrites the saved image but sets instead next new values for the Profile and Comments checkboxes of the Save Image dialog.
However, if for example, the Quality value is changed using the slider in the Save File (JPEG) window, the image already saved is evidently overwritten - its size changes once the Save Again button is pressed.

David

ksinkel
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Re: EXIF/ IPTC removal

Post by ksinkel »

David,

If your intention is to save the file without comments, you should uncheck 'Include Comments' in the Save As dialog. There is no reason to wait for the little statistics popup (i.e. Save File - JPEG).

That said, I can confirm that there is a bug in the Save File (JPEG) dialog in that comments are saved even when the setting is to not save them. However, as you point out if you =change other parameters like quality or depth, you do get the expected behavior.

Kiril
Kiril Sinkel
Digital Light & Color

davidh
Posts: 748
Joined: June 9th, 2009, 2:16 am

Re: EXIF/ IPTC removal

Post by davidh »

I was trying to save a file without the redundant properties listed under the Original Exposure label in the User Comments dialog box, see the attachment. But it cannot be achieved with the Save Image dialog box. There is no checkbox "Include Only User Comments". Unchecking Include Comments removes not only Original Exposure properties but also User Comments. To get the User Comments back it needs reopen the already saved jpeg image, reenter the User Comments and resave, which might increas image degradation depending on the Quality and Sampling setting.

The other method already mentioned, Copy and Paste, also removes both Original Exposure data and User Comments, but enables reentering the User Comments and save only then therefore once. A question is how big image fits into the Windows Clipboard and what else happens to the image inside the Clipboard besides stripping some of the its metadata. Also it is not a nice method since it happens outside the Picture Window, or at least I have such feeling.

PWP Copy tranformation under Geometry also creates copy of the image but does not strip the properties like the Windows Clibboard, so it evidently works differently. Perhaps it might offer a simple box with a list of options similar to the one in Save File (JPEG) that would enable preserving User Comments together with the Profile, Statistics etc. This copy feature would prepare the image for saving later in whatever format. Just an idea.

David
Attachments
Redundant Properties.JPG
Redundant Properties.JPG (15.3 KiB) Viewed 3054 times

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