Need Some Technical Advice on Erradicating Meta-data. / General Chatting / Forums

Forums

4hv.org :: Forums :: General Chatting

« Previous topic | Next topic »

Need Some Technical Advice on Erradicating Meta-data.

1 2 next

Move Thread

LAN_403

Patrick

Sun Nov 27 2016, 09:02PM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

First, Im not a criminal.
Second, Im not planning any criminal acts.
Third, Im not planning any terrorist attacks.

Background:
So Im a volunteer for a company that does high altitude (+100,000 ft) research. Im allowed to take as many pictures as I want, of anything for personal use. But Im only allowed to publish some of what I know, due to funding partners and intellectual property concerns.

We've also had occasions where well meaning people have followed us into the desert and gotten lost. So were more secretive about locations and dates of flights now.

Question:
When I take pictures with my new camera, I can see all kinds of data in the properties window. But what about hidden data ? I need to obliterate all data except the image pixels themselves. Will going into a photo application of my choice, doing my changes, then saving as a different jpeg (not saving over the original) be enough ? Else how am I to accomplish this need.

Ive seen programs like "EXIF Purge" but dont know if thats a great idea or not.

I may post a secret pic for some of you I trust in a special location for a limited time, youll be able to test my method that way.

Avalanche

Sun Nov 27 2016, 09:12PM

Registered Member #103 Joined: Thu Feb 09 2006, 08:16PM
Location: Derby, UK
Posts: 845

The way i'd do it:

Open the original JPG, save as .PNG (lossless, and has no metadata)
Open the .PNG, save as a new .JPG

That should pretty much guarantee nothing slips through...?

Bjørn

Mon Nov 28 2016, 01:22AM

Registered Member #27 Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058

.PNG has metadata so converting to it is not a 100% safe method since the result will depend on the program you use.

In windows 10 you can right click on an image and go to

Properties/Details tab/Remove Properties and Personal Information

Programs like GIMP and Photoshop can save files without the metadata.

Carbon_Rod

Mon Nov 28 2016, 05:56AM

Registered Member #65 Joined: Thu Feb 09 2006, 06:43AM
Location:
Posts: 1155

"Photoshop can save files without the metadata"

Adobe uses watermarks instead.

Kizmo

Mon Nov 28 2016, 06:37AM

Registered Member #599 Joined: Thu Mar 22 2007, 07:40PM
Location: Northern Finland, Rovaniemi
Posts: 624

Internet is full of Exif metadata removal services but i prefer downloadable solution such as this one:

I can confirm, this one works fine :)

EDIT:

Whatever removal software or website you choose, you can test the success with this website:

Hydron

Mon Nov 28 2016, 09:56AM

Registered Member #30656 Joined: Tue Jul 30 2013, 02:40AM
Location: UK
Posts: 208

Irfanview has some handy options for metadata when you save a file.

The other way to deal with it would be simply to open the file, ctrl+c to copy the image, paste it into another program/window (as raw pixels from the clipboard, no metadata involved), save it as a new .jpg. For the web you're probably going to recompress the image anyway so wouldn't even lose any quality vs working directly with the original.

Dr. Slack

Mon Nov 28 2016, 04:46PM

Registered Member #72 Joined: Thu Feb 09 2006, 08:29AM
Location: UK St. Albans
Posts: 1659

If the image is low enough resolution to fit on the screen, display it and take a screenshot.

You could use something like python's image library which allows you to programmatically read/write/fake/destroy side data to your heart's content.

Patrick

Mon Jan 23 2017, 01:27AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

Ok Ive got quite a few pics up now, I didnt eradicate all the meta data. but for those who want to see here is the site :

If you want to look for errors or other troublesome mistake please do id be grateful.

When "Tech TV" was around here in the US, one of the hosts, (beautiful i will say) uploaded a normal pic, but someone out there went through it a found a low res thumbnail, of an undressed nature she had taken of herself.

I dont know how that could happen, but it did. And if i screw up some intellectual property rights my group will kill me, as we've had others steal our work before.

Bjørn

Mon Jan 23 2017, 05:21AM

Registered Member #27 Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058

JPEG files can contain lower resolution copies to speed up preview and thumbnail generation. If you crop the original picture in a program that does not regenerate the lower resolution picture then you can end up with the full body in one picture and a head in the other. Post it on the internet and it will just take seconds before someone finds out.

Plasma

Mon Jan 23 2017, 05:24AM

Registered Member #61406 Joined: Thu Jan 05 2017, 11:31PM
Location:
Posts: 268

@Patrick
Modern camera put a 4 byte hex value in the file, that is tired to the camera, open photo's from the camera in a hex editor and see what values are the same in different pics, replace with 0x00000000, and then see if you can still see the picture.

1 2 next

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob