Q. I used a data recovery program to recover lost images from my digital camera. Unfortunately some of them came out grey. Meaning, when I look at the picture as a thumbnail, I can see the entire picture, but when I open the image, a large portion of it completely greyed out. Any idea of how I can fix these images? I've tried recovering them twice and both times the same images came out damaged.
A. The photos are damaged. The embedded thumbnails appear fine because they were pre-generated. Think about it like a lock and key: if one tooth of a key is missing, it'll still fit but it won't unlock the door. Recovery may be possible but only if you know what you're doing.
Here's how one person capable of preforming these recoveries describes the condition:
" - Grey Areas in your Image
In various forums on the internet, people have incorrectly stated that photos are unrecoverable if they contain gray areas. This is not usually true. Some JPEG decoders are very picky with how they recover from errors and simply report Drawing Failed (in Windows Picture and Fax Viewer), while others might draw a middle-gray region or just display a "Red X". In some cases the gray area is in fact completely damaged (overwritten by unrelated data), but this is not always the case.
- Why do JPEGs get damaged?
There are many sources of damage to photo files, but the most common reasons are:
- Photos were deleted or formatted & a "recovery" utility was used
- Memory card / hard drive error (logical or physical error)
- RAM failure
- File transfer / interface error (memory coherency issues, buffer over/underrun, etc.)
- What Happens when you Open / Decode a Corrupted JPEG?
Even a single byte changed in a JPEG file can cause an image to be unrecognizable (or not open at all). Why? Because of the way JPEG compression is designed, images are stored in tightly-packed streams of binary bits (not bytes). Each pixel can be represented by as few as 2 bits to as many as 26 bits (dictated by the variable-length Huffman Coding scheme). To make matters worse, in an effort to keep the compression as efficient as possible, there is virtually nothing to indicate where you are in the stream of bits (unless Restart Markers are used). Therefore, as soon as a single bit is encountered wrong, the millions of bits that follow will be decoded incorrectly as well. The manner in which DC and AC coefficients are arranged in MCUs means that this corruption often shows up in shearing, wild color shifts and many other visual phenomena."
- http://www.impulseadventure.com/photo/fix-corrupt-jpeg-photo.html
It appears from the examples and comments that he or she is fully capable of preforming JPEG recovery when such operation is possible. Unfortunately, the author no longer accepts recovery requests.
There are similar JPEG recovery services available but your photos should be worth the cost. Here's one example (I don't know the reputation of the company so I can't recommend it):
http://www.jpeg-repair.org/
The company above seems to recover a small number of JPEG submissions for free for their own analysis and your benefit.
There are a number of recovery tools available too, but unless those pictures are very important they aren't worth the money; you don't know for sure if the files are recoverable, but mostly because you'll only have the programmers word that it even works.
http://www.google.com/search?client=opera&rls=en&q=jpeg+recovery&sourceid=opera&ie=utf-8&oe=utf-8
Here's how one person capable of preforming these recoveries describes the condition:
" - Grey Areas in your Image
In various forums on the internet, people have incorrectly stated that photos are unrecoverable if they contain gray areas. This is not usually true. Some JPEG decoders are very picky with how they recover from errors and simply report Drawing Failed (in Windows Picture and Fax Viewer), while others might draw a middle-gray region or just display a "Red X". In some cases the gray area is in fact completely damaged (overwritten by unrelated data), but this is not always the case.
- Why do JPEGs get damaged?
There are many sources of damage to photo files, but the most common reasons are:
- Photos were deleted or formatted & a "recovery" utility was used
- Memory card / hard drive error (logical or physical error)
- RAM failure
- File transfer / interface error (memory coherency issues, buffer over/underrun, etc.)
- What Happens when you Open / Decode a Corrupted JPEG?
Even a single byte changed in a JPEG file can cause an image to be unrecognizable (or not open at all). Why? Because of the way JPEG compression is designed, images are stored in tightly-packed streams of binary bits (not bytes). Each pixel can be represented by as few as 2 bits to as many as 26 bits (dictated by the variable-length Huffman Coding scheme). To make matters worse, in an effort to keep the compression as efficient as possible, there is virtually nothing to indicate where you are in the stream of bits (unless Restart Markers are used). Therefore, as soon as a single bit is encountered wrong, the millions of bits that follow will be decoded incorrectly as well. The manner in which DC and AC coefficients are arranged in MCUs means that this corruption often shows up in shearing, wild color shifts and many other visual phenomena."
- http://www.impulseadventure.com/photo/fix-corrupt-jpeg-photo.html
It appears from the examples and comments that he or she is fully capable of preforming JPEG recovery when such operation is possible. Unfortunately, the author no longer accepts recovery requests.
There are similar JPEG recovery services available but your photos should be worth the cost. Here's one example (I don't know the reputation of the company so I can't recommend it):
http://www.jpeg-repair.org/
The company above seems to recover a small number of JPEG submissions for free for their own analysis and your benefit.
There are a number of recovery tools available too, but unless those pictures are very important they aren't worth the money; you don't know for sure if the files are recoverable, but mostly because you'll only have the programmers word that it even works.
http://www.google.com/search?client=opera&rls=en&q=jpeg+recovery&sourceid=opera&ie=utf-8&oe=utf-8
How to recover data after partitioning Mac hard drive?
Q. I re-partitioned an external hard drive that had both Windows and Mac partitions. Is there a way to undo this to get the data back?
A. If you want to ba able to recover anything from it, do not install/write anything else to that drive.
Testdisk / photorec can be used to recover almost any recoverable data.
http://www.cgsecurity.org/wiki/TestDisk
There are plenty of other programs out there to do this as well, and quite a few that are open source (like TestDisk) or otherwise free. Though most of them are commercial proprietary programs ($$$).
I use Testdisk and PhotoRec mostly for data recovery.
A bootable CD that includes testdisk/photorec and other similar forensic programs is Knoppix STD.
http://s-t-d.org/
http://en.wikipedia.org/wiki/Knoppix_STD
One issue with most such programs, at least of the free/open source variety, is that you need more of a technical knowledge of computers to use them properly.
Usually Windows partitions are relatively easy to restore as long as all that was done was a relatively minor change. Meaning, no new data files written to the disk. I'm not that familiar with Mac partitioning though.
Your alternative is to pay someone or a company that specializes in data recovery. For an idea on cost for this option, my rates for such start at $100/hr.
Testdisk / photorec can be used to recover almost any recoverable data.
http://www.cgsecurity.org/wiki/TestDisk
There are plenty of other programs out there to do this as well, and quite a few that are open source (like TestDisk) or otherwise free. Though most of them are commercial proprietary programs ($$$).
I use Testdisk and PhotoRec mostly for data recovery.
A bootable CD that includes testdisk/photorec and other similar forensic programs is Knoppix STD.
http://s-t-d.org/
http://en.wikipedia.org/wiki/Knoppix_STD
One issue with most such programs, at least of the free/open source variety, is that you need more of a technical knowledge of computers to use them properly.
Usually Windows partitions are relatively easy to restore as long as all that was done was a relatively minor change. Meaning, no new data files written to the disk. I'm not that familiar with Mac partitioning though.
Your alternative is to pay someone or a company that specializes in data recovery. For an idea on cost for this option, my rates for such start at $100/hr.
How Do I make my Laptop Safe to Sell?
Q. I want to buy a new laptop and sell my old one. But I want to make sure that the next owner can't tap into my personal info, like my web browsing, emails, and such. How can I do that? Should I run the recovery disk on it a lot of times?
PS- any good laptop recommendations as well? I want something fast and that has wifi.
PS- any good laptop recommendations as well? I want something fast and that has wifi.
A. If you want to be extra careful, you can do a sanitization of the disk before re-installing the OS. A good open source program for this is Eraser:
http://www.heidi.ie/node/6
You can make a boot disk that will allow you to do a repetitive format of your drive, which will overwrite each section of your drive with ones, then zeros, then random white noise. It will do this several times (35 is recommended by DoD standards), and will probably take a long time, maybe even a few days depending on the speed of the drive.
Once this format series is done, you can re-load the OS with the OEM disks and be sure that your personal data is completely gone.
I usually do this with Hard Disks before I sell them or give them away.
http://www.heidi.ie/node/6
You can make a boot disk that will allow you to do a repetitive format of your drive, which will overwrite each section of your drive with ones, then zeros, then random white noise. It will do this several times (35 is recommended by DoD standards), and will probably take a long time, maybe even a few days depending on the speed of the drive.
Once this format series is done, you can re-load the OS with the OEM disks and be sure that your personal data is completely gone.
I usually do this with Hard Disks before I sell them or give them away.
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