Dummy made a fault: saved scans as RAW

[Homer-j-s]

Hey.
Hopefully somebody can help me ....
I scanned some photos with my CANON multifuntional scanner using IrfanView. Then I saved them as Raw files by fault. Now I don't have the original photos anymore. No matter which program I use, everytime I open oine of the scans I only see a gray fuzzy stuff. I tried some raw converters, but I always had to tell the image size, channels and stuff like that. I don#t have these informations.

Does one of you know how I can convert these files to a readable / viewable file like tif or jpg?

Thanks.

[Bhikkhu Pesala]

Since I don't have a camera I've never seen a RAW image. What does File, Open as, RAW do if you open your files from there?

[Laurent]

Hi Homer-j-s,

Why RAW? RAW means brute data. Nothing to do with DSC's RAWs which contain brute data AND infos about image size, and so on.

IrfanView needs these info to be able to display the image correctly.



So, if you don't remember them, you need to "guess" them. Or retrieve them. It may be a long work...

Let's be clever

One info is the image size (width w, height h). Get the exact file size (Windows Explorer, Properties, Size on disk). Divide by 3 if it is a 24 bpp image. If the result isn't an integer, . But if it is an integer, it is equal to w * h. Search possible values of w and h. Almost certainly several pairs are possible. Try the couple that might match the format of your image.

Another info is the BPP. It is probably 3 for a 24 BPP color image. But other values are possible according to what you choosed when you saved your image.

For the rest, try, as I tried. I had to use
- File header size: 0
- 24 BPP (no YUV)
- Color order: RGB
- Interleaved (RGB RGB)

Good luck.

Just a tip : just after you save an image (especially if you are not accustomed with that format) open it to check

Laurent

[Homer-j-s]

Thanks for the fast replies.
I feared your answer. I tried it yesterday, and of course it's not an integer. I tried to divide through 2, 3 and 4 (16, 24,32). I also tried it with 1 byte header to have an integer for 24 bpp. I used the results in excel and divided through all possible values amd tested to open the file with the integer values that came out- without success. Is there no other way to get the picture out of it? Thanks again for your help.
File size is 9445376 bytes, it was scanned with 300 dpi and 24 bpp. Image was originally 15*20 centimeters.

[Laurent]

Hi Homer-j-s,

Well, here is a new "game", like Sudoku
What about a header of 32768 bytes (2^15) and 1532 * 2048?
Other combinations possible.

Tip: scan a new document and save it as RAW, but note the default values IrfanView uses. Maybe they are the values for the other files.

Laurent

[Laurent]

Better tip: scan a very very little portion of an image (some pixels) just to have a rough idea of the header size.

[Homer-j-s]

Thanks Laurent, you're the man

Okay, shame on me. Better not to tell in which sector I'm working ....

If you look at the properties of a file, there are two fields that show different sizes: the real one and the size on the disk. Laurents way to get the pictures back were fully right but I choosed the size value on the disk instead of the real size. This is why I never got the integer value after dividing the size by 3.

With the real size it was a piece of cake to get the h/w value and get the pictures back. Finally I was able to save them in a "better format".

Laurent, thanks a lot for your help.

Cheers

[Laurent]

Really happy you succeeded

Laurent

[Sam_Zen]

A suggestion to place this thread in the TechDoc department, because this has a valid solution for a technical problem.
A sidenote : I don't think centimeters are relevant in this proces.

[matera]

Hooray for Homer! Now that's what I call an educational experience - and I'm glad we could all share it here.