There is a very fine line that exists in the photographic community when it comes to post processing, this line is the line that separates an image from being a photograph from an image which is manipulated and can no longer be classified as a photograph.
But before I discuss the above, let me delve a little in the technical side of photography.
Lets start with the eye. The human eye is an extremely powerful organ capable of defining features and structures in extremely low light. The human eye is so powerful that nothing in both film and digital comes close to capturing the detail, the colours, the mood or even the range of light you are able to see and as a result we have always found the need to manipulate (perhaps not the right word) an image to return some sort of reality to the image. The human eye is capable of seeing a far greater range of light and tonal variances then the digital sensor or film.
Secondly, capturing images in RAW. RAW images are pretty easy to understand. RAW files are unprocessed, uncompressed image data which in order for it to become a photo needs to be processed correctly (within limitation) using lightroom or photoshop or whatever other programs you may use.
Now where is the line that defines a photo and an image that has been manipulated.
This line varies from person to person and is a very subjective idea but to me, a photograph is an image which has been captured in RAW, JPEG or any other file format, imported onto a computer and once brought into post processing only minor post production is applied to the image (similar to what you could do in the darkroom with film, (ie. exposure, contrast, white balance etc)), whereas photoshop manipulations is where an image has been edited to create a unrealistic and unnatural image as well as where certain elements are either cloned out or replaced.
Black and white photographs are still classified as photographs because you make the decision to convert an image to black and white, in the days of film, you would shot onto black and white film, but in today's age it is a far easier process in lightroom or photoshop.
The excess of good post production is to edit and bring back a photo to what your eyes saw in a specific scene or to edit for a specific purpose and to create an iconic and unique image.
Let me show two examples of images and I will explain what I did to them individually.
This is an image I captured in Botswana. I would classify this image as a photoshop manipulation.
Original on the left, edit on the right.
I have blown out the highlights, lifted my shadows, increased clarity, increased contrast, lowered exposure and sharpening the image.
Exported to photoshop, luminosity layers added to bring a little more detail into both highlights and shows, and further increase in sharpness and contrast.
All stuff you could do in a darkroom but for this image I edited for a purpose and made the image quite unnatural looking.
Cropped to get rid of the distracting car parts that where present when I took the image. Converted to black and white. Slight increase in contrast, exposure, white balance, slight amount of dodging and burning.
Image seems like a natural scene you would find in Kruger, editing is not over the top and does not change the mood of the image.
I hope this clarify's a few things for you as this is the basic editing theory I put into place and I think it is a theory quite a few photographers have when it comes to post production.
Left me know what you think and what your thoughts are.