Choosing Image File Format for Data Recovery

[viking]

I have a failing hard drive and would like to create an image file that I can use to recover the data from. However, I would like to be able to use this image file with several data recovery programs, including R-studio, Active@ Undelete, GetDataBack, UFS Explorer etc. I believe that the best type of image would be a raw data (binary) image of the whole drive ("raw disk image")?

Thus, I need to find a third party application that can create such an image and can be read by various data recovery programs. However, I am confused about the different formats for disk images (are there different formats for raw disk images??). For example:
R-Studio can read image files with file extensions: rdr, dsk, dat, bin, dfs, fss, hex and arc
Active@ Undelete can read the following image files types: Raw Data (Binary), LSoft, Virtual PC, Virtual Machine (VMWare)
GetDataBack can read image files with file extensions: img, imc, vim
UFS Explorer ???

Which of R-Studio's extension(s) refer to raw disk image files? I assume that R-studio can not create raw disk image files (only a proprietary disk image format)? Any suggestions of a third party application that can create raw disk image files to be used with R-studio (and the other data recovery programs?

[Alt]

R-Studio can create raw (uncompressed) disk images. Just select the Byte to byte image option. See R-Studio's help for details: Images.
The file extension doesn't matter, you may select whatever you like, and change it if necessary. Raw file images are just data from disks, no additional information.