Saved digital images go bad

[keiththirgood]

I've run the surface scan (It took 15 hours). All sectors are fine. No bad bits were detected. So what else could make photo files go bad?

 

[Garbz]

When you ask if my computer is rock solid, it gets a bit complicated. The files are stored on my server, and my partner and I access the files from any of four other computers. These are all Macs, so they fundamentally run on the Mac version of Unix, which makes them very solid.

I'm not talking about instabilities due to software bugs, I'm talking about instabilities due to an unstable system performing incorrect calculations or getting random corruption issues in memory. In any case the answer sounds like your system is stable.

What about software? What software do you use to copy, edit, view, etc?

 

[keiththirgood]

Hi Garbz
As it's a Mac, most of the software I use is built in, and the damage to the files can be see without opening the file. I can see it in the icon that the Mac shows when I select an image, before the image is even launched. So I'm not sure what relevance things like Photoshop will have, when they are not yet in the equation.

This is why I'm really puzzled. The image file is copied from the camera's chip to the hard drive. I check all images after transfer using the preview function of the Mac. (They are not being opened, only previewed while they remain on the desktop.) The files might be untouched for days, weeks, years even. Then we decide to look for interesting images from a trip, and begin quickly previewing them. (This is much quicker than actually opening them.) That's when we discover the bad images. So no software has been interacting with the files since they were put on the hard drive. Yet the hard drive checks out as having no bad sectors.

 

[ClickAddict]

.... I access the files from any of four other computers...

Did you run the memory scan on the other computers. Perhaps one of them is opening the files and corrupting them and then saving to the Raid drives.

 

[keiththirgood]

Hi ClickAddict,

I didn't, however, it's only my partner and I in the shop and I know what she is doing at all times, so I know she has not been at the files. (For the most part, she doesn't know where the files reside, and is constantly asking me to find files. She's an artist and isn't much on organization.)

 

[banderson]

Keith, command+shift+4 should allow you to select and do a screen shot. Unless there is some block not allowing you to do it. Just my two cents

 

[keiththirgood]

Hi Banderson,

I'm not sure what you're referring to. I have no difficulty taking a screen shot. Remind me what your answer is for.

 

[banderson]

Hi Banderson,

I'm not sure what you're referring to. I have no difficulty taking a screen shot. Remind me what your answer is for.

You said your system wouldn't allow. I thought you meant that you couldnt take a screenshot- when you meant that you couldn't post it here. Lol

 

[Austin Greene]

Over the years I've found a number of saved digital images go "bad". They acquire stripes and other defects, sometimes minor, often major. These defects occasionally happen right at transfer from the card to my hard drive, at other times they have been opened at least once (often many times) and suddenly they are bad. This happens with jpegs and with Raw files as well.

I would upload a screen shot to show you what I mean, however, the system will not let me do so.

Any idea what might be going wrong and how to prevent it?
Keith

Its a symptom of how anything digital works. Your constantly writing, copying, and rewriting data.While the error rate is incredibly small, you do on occasion get mistakes that happen. As has already been stated, the best thing to do is to backup your images. I personally never touch any of my original images. If I am going to do any PP, its always on a duplicate so I will always have the original to go back to.

 

[keiththirgood]

Togalive, I agree.

However, these images are in RAW format and have never been touched since they were first copied to the hard drive and checked in preview to ensure they copied cleanly from the camera to the hard drive. Long after the original copying is when the problem was discovered. It was discovered by looking at them in preview, not opening them. So the files have not been copied and re-copied for small errors to have crept in. Most of the degradation has been in untouched files. Only after I discover a damaged file do I open it in photoshop to see if it's the shot or the preview that's damaged. It's always the shot.