Cameras and cards · partial corruption · ADR-2025-3667
The Preview Opens. The Photograph Does Not.
He could view the thumbnails but he could not view the full-size photos. His raw files appear to be corrupt
, he stated, even though he could still see the thumbnail images In preview
, and when viewed normally, they would come up white, with coloured lines across them
. All images displayed this same behaviour. He had the CompactFlash card that contained the original photos, along with a set of identical copies stored on a hard drive, and he wished to determine whether he should work with the card or the hard drive.
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What failed, and why.
RAW files are two pictures in one wrapper: There is a small preview written to allow a camera to display something immediately. There is full resolution data, which is much larger and located elsewhere within the file. When viewing the RAW data, a viewer will show you the first part (preview), but fail on the second (full size image). This is exactly what he described. Therefore, the corruption does not exist everywhere. It has reached the larger section of data and spared the smaller section. Since we can eliminate general corruption, we have only two options left: either the full data was never completely written out, or the full data exists but the card is returning incorrect information when asked to read it. These two possibilities would lead to different results. And thus determining between them is the entire diagnosis process.
What the bench did with it.
The order of the job →| Equipment used | Its work on this job | The reason for it |
|---|---|---|
| PC-3000 Flash | One controlled read of the card made in full prior to any analysis of images | Directly reads the flash off the chips, going around the controller, with a maker-ID library kept updated here |
| R-Studio Technician | Then both sources were compared file by file, and the cleaner of the pair was selected each time. | Constructs an array from the images, and reads nearly every file system |
| UFS Explorer Professional Recovery | The card’s own file system was accessed via the copy, and then each frame was retrieved from it and shown on screen. | When other applications will not open it, this application will open APFS, ReFS, XFS, ZFS and Btrfs. |
What the bench did with it.
Copy both sources before reading either
Duplicate copies were made of both sources. Before either could be examined, both versions were copied: the card behind a write blocker on a controlled reader, and the drive containing his copies. All following actions took place using these copies. Having two versions of identical photographs is helpful in nature, but only if neither version can be altered during the comparison period.
Find where in the file the damage sits
Instead of opening each file in a viewer, they were opened at byte level. The boundary between the intact preview and the damaged full resolution data was identified within each file. This is what separates frames that were never completed from frames that are complete on the card and being returned incorrectly. The first option is limited by what exists. The second option is a reading problem and reading problems can be worked on.
Then read the card again
When the error appeared to be a read error rather than a write error, the card was reviewed again at a lower level and cleaner full-resolution data returned for a number of the frames. When the data had never been fully written, regardless of how much re-reading is done, no additional data is added, so these frames are what they are. He was informed which of his files belonged to which category.
What went home.
The images were returned at their highest resolution based upon what each individual file supported. For most files, this means the entire frame. For the remaining files, it means the preview size and no more. No recovery description was given to an image until after it had been opened and viewed. A card or memory stick carries the published price of £250 + VAT. The examination determines whether your fault is due to a reading issue or a writing issue. It costs nothing.
Begin here if yours is doing the same thing.
More jobs where files would not show and volumes would not read.
Yours doing something similar? Power it down first.
Published prices are fixed. Memory cards and USB sticks are £250 + VAT. Any stand-alone drive is £300 + VAT. Drive configurations containing multiple disks (RAID, NAS or server) start at £500 + VAT. First assessments are always complimentary. Thereafter, data recovery charges are also fixed in advance and in writing, so you'll always know how much you owe before paying any money. Shut it down, get a quote first (by phone or with the form), then send it in or drop it off at our Guildford intake laboratory, Monday to Friday, 9am to 5:30pm (no appointment needed). On most jobs you only pay if we recover your data.