During a recent photography course in South Africa I was strongly advised to download and use free Raw Processing Software before editing in Aperture 3. As a relative newcomer to working in Raw, I had not previously been conscious of the difference between Raw Processing and editing and have been processing and editing Raw files in Aperture 3 (on an iMac with OS X Lion).
By way of rationale, I was told that unprocessed Raw files contain separate layers of colour whereas files opened in Aperture 3 will already have had those layers compressed into one layer, presumably meaning that any alteration to green would also alter blue and red etc and vice versa. Shooting on a Canon 7D, I have tried on returning to London to download and use the DPP software for Raw processing but have immediately encountered a block indicating that it is not suitable for use with my iMac software (though the DPP software does claim to be compatible with MAc OS X version 10.2-10.8.)
I fear that I may have misunderstood what I was advised in South Africa as, even if I could could get it to function, this workflow pattern of using Canon's raw processing software prior to using Aperture 3 does seems inordinately complex and time-consuming. What (if any) harm would I be doing to my Raw images and/or what would I be foregoing if I simply reverted to my previous practice of downloading my Raw images straight into Aperture 3 and processing / editing them there?