I'm not sure what validity there is to these statements. Afterall, when I upload the file to a hosting site and have other people download it and open it, the file is not corrupt. I'm not talking about uploading it from the flash card either. It's the copy that is already on my hard drive and is supposedly corrupted by faulty RAM. Which btw is not detectable by any memory testing software I've run.
My thinking is that these images make it to some sort of memory cache when they are loaded, and then this cache is paged out to disk and every time you go to open that file it's retreived from there rather than the original file. Perhaps if I discard my windows page file these so called corruptions will go away.
Another interesting symptom I noticed which makes me think it's some corrupted caching mechanism rather than bad ram is that if I transfer a file over the "corrupted" one from the flash card it is most of the times fixed, but Bridge has a hard time recognizing it. Even after I purge the Bridge cache and regenerate the thumbnails they show up messed up. I actually need to open the file in Camera Raw. It shows up all messed up for about 5 seconds and then clears up. After that I can close it, Bridge will show that it has been edited, then I can purge the Bridge cache, and only then will the thumbnail generate properly.
All this makes me think this is another cache (not the bridge thumbnail one) that isn't quite right.
Does anyone here know what Camera Raw actually does when it shows the raw image on the screen, in terms of whether the original RAW data is rasterized or a JPEG file is generate on the fly and displayed to the user?
You are free to believe what you want, no one would dispute that.
All software RAM tests miss some problem RAM sticks, Photoshop is the ultimate RAM tester.
RAM may not corrupt images, but it can sure go berserk when opening them.
ALL the symptoms you describe point to hardware problems.
The ONLY way to rule out bad or problem RAM is by a process of elimination, taking out the sticks (RAM modules) and putting them back one (or a pair) at a time.
I opened your file, and other than a good amount of totally blown highlights, the image opens without any problems. Others have told you they can also open it. Obviously the image is NOT corrupted. If you open the image in Photoshop and print it, you'll be able to tell whether it's bad RAM when the artifacts print. If they do not print, then suspect a faulty graphics card, but that is less likely.
A failing hard drive would in fact be corrupting the files permanently, but that is not the case here.
No one can guarantee it, but my money is on bad RAM.
>whether the original RAW data is rasterized or a JPEG file is generate on the fly and displayed to the user?
Neither, and most certainly not the latter. That would be ridiculous, ludicrous and absurd.
You need to read on what raw images are.
In a nutshell, a raw image is a very, very dark linear grayscale image, containing no colors at all, not anything that any human being can perceive or interpret as color.
It is the job of the converter (in this case ACR) to demosaic the image, create the color based on the information supplied by the description of the sensor and the filter array according to the algorithms designed by the developer of each individual converter, apply a gamma and tone curve, and put such a demosaiced, nonlinear image in RAM for Photoshop to display. It is not saved in any format until you, the user, chooses to save it, hopefully as a PSD or TIFF, but at that point ACR is not involved, any morejust Photoshop.
While being shown to you in the ACR Preview is also the demosaiced, rendered non-linear conversion of the image in RAM.
There are a few things that can be going on here. The RAW file has an embedded jpg for quick previews. ACR gives the option to use this jpg in Bridge for the thumbnail or to create a high-res thumbnail using the original RAW file. There could be a difference between these two for you. I had the same problem you did and tried all the same stuff you did. The only difference is when others would open the file it would still be corrupt unless they opened the embedded jpg. That was always OK.
What I finally found to be the problem for me was my USB. I installed a PCI-USB card and used that instead of the onboard USB to transfer my files from camera/memory card to my computer and never saw the problem again. I found this out because some images that were not corrupted became corrupted when I transferred them to my USB backup drive.
Just something for you to check out.
YES A POSSIBLE SOLUTION (cut-to-the-chase at the bottom):
iMac - 2.33Ghz core2duo - 4GB RAM - Snow Leopard
External USB 1.5TB+ where the RAW files go
Lexar firewire 800 CF card reader (this was introduced into my workflow... things started to get corrupt when I factored this into the equation)
Genaric USB card reader
16GB Kingston @ 133x (a few of these... could be the problem too)
16GB SanDisk Extreeme III 30MB/s
Lightroom 2.5 (CAMERA RAW 5.5)
back story: I've only been searching for about a few hours (after I discovered the corrupt files). I called Adobe... not the people you want to call when you have a fustrating situation like this... cause you get and indian guys, who is hard to talk to and super slow and pretty much said there is no solution. He didn't see if there where other people who had this problem or ask another support person... just cannot fix it. Shame on Adobe for hiring people who are hard to talk to and don't really understand. Adobe support = F in my books.
Sorry, back to the backstory. I had no problems or any corrupt files until recently. I would get one here and there, but no to the point that ever twenty pictures a few in a series would be corrupt and have white and pink lines and such.
Possible problem: There could be multiple factors it could be, and I'm slowly pining them down. I ultimately think it is combination of equipment I have especially pertaining to the LEXAR Firewire 800 card and the Kingston 133x cards. I'm definitly gonna change up my combination of equipment. My speculation is I think the LEXAR 800 is ripping the files too fast from the card reader.
I faced the fact... this is an project from a month ago and I've used my CF cards numerous of times, so I know the pictures are gone... no way to recover them from the cards again. So I did find a program called FILE JUICER (mac only, sorry) that extracts the JPG from the RAW file. Works great... even better is that the JPGs are all 21 mega pixels, yippie! So thanks File Juicer for saving the day!
I hope the person who ends up with the same problem will find this post.