luisrrjjcc wrote:I am going to use the HDD Raw Copy tool to create a copy of a hard drive and mess up with it to see what can I recover.
You haven't described the state of that disk, or whether this is just a test, for anyone to advise you about your plan. Assuming that you have accepted the risks and are going ahead anyway, then...
luisrrjjcc wrote:What format should I use for the output, img or imgc?
If you are creating a clone file for subsequent recovery, as you seem to be doing, I recommend using
img - that is a standard uncompressed file, which several recovery programs can read (unlike the compressed imgc format, which is more appropriate for other uses).
luisrrjjcc wrote:After creating it, what program do I use to open it?
There are many recovery programs which can read uncompressed disk image files - your choice of recovery program depends on many variables.