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Photographic manipulation

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It's easy to start up a lively discussion among photographers, on the ethics of manipulating photographs.  Modern photography incorporates digital techniques now as standard tools.  In my work I encounter photographs that range from straight calibrated photochemical film images to megaprocessed hyper-composited barely-recognizable-as-a-photograph technical and artistic tours-de-force.

There are many who would object to the latter as not being "real" photographs, but this is to deny the amazing breadth of photography as a scientific tool, a communication mechanism, and as art. In all of these it is the information in the image that is important, and image-workers will do whatever they can to bring out the information they are after.

As a result there is a continuous spectrum of techniques that are applied to photographs, digital and otherwise. Many of us confine ourselves to one region of this spectrum, for reasons of personal taste or aesthetic and ethical sense. My own sense of where to draw the line falls somewhere between making overall "global" corrections to an image and making localized edits to it (with the exception of removing dust and scratches). But my rules will bend depending on the purpose of the picture. I will leave the airplane trail in pictures like Deep Zumbra Sky and Platte Lake Trails. I consider them to add an artistic, or at least intriguing, element. But I will (usually) remove them when I combine frames for my Milky Way panoramas.

Consider another of my self-imposed restrictions: there is a challenge in obtaining a composition by being at the right time and place. Some compositions can be obtained by cutting and pasting the elements, and this would certainly be an easier and less expensive way to obtain the result. (Be careful if you do this: I have seen too many full moons placed in positions that are astonomically not possible).

But the final image is not the only purpose. This would be the equivalent of bringing a fish home from the market. If the purpose is to eat fish, this is a fine thing to do. But if it is to enjoy the process of finding and catching a fish (a process which far exceeds its caloric content), then this is a failed effort. I find that there is actually quite a bit in common between the amateur astronomer and the avid fisherman!

So here is my list of photographic manipulation techniques arranged in the order that they fall in my personal spectrum. The rank in this list is an indication of how much "editorial" component is included in the final result.

None

There really isn't such an item as "none". It is not possible to make an image without some attribute that could have been different. The type of film, the chemical processing used, the paper type it was printed upon or the response of the scanner that digitized it are all examples of implicit choices that impact the appearance of the picture. But I include it here to serve as a baseline reference for the items that follow.

Retouching dust and scratches.

Most people find this a highly acceptable thing to do. The dust was certainly not an element of the original scene, and scratches are distractions that are artifacts of the physical medium embodying the image.

Adjusting contrast and color balance

This has always been a standard tool for photographers through their choices of film, paper types and processing chemistry. What many people don't realize is that modern color negative film requires a judgement to be made about the lighting in the original scene. Variations in C41 film development causes a loss of this information, which must be restored when the negative is printed.

(Global) histogram and arbitrary color curve adjustments

This is an extension of the simple contrast and color balance control that is made possible by digital image tools. Wild changes in image appearance can be made in this way bringing out detail or colors that could not otherwise be obtained by photochemical methods. The judicious application of these adjustments yield great gains in overall image appearance.

Superposing multiple frames of same image

This is a noise reduction technique, clearly with the intent of increasing the information "signal"

Localized color adjustments, vignette compensation

These are intended to bring the dynamic range of a scene within the range of the photograph. Sometimes by varying the exposure over different areas a better view can be obtained. Your eye and brain do this automatically when looking at a scene. Photographers have long done this by "dodging and burning" during the printmaking process.

Global image processing methods, sharpening, smoothing, filtering

Sophisticated techniques are made possible by digital means. Some people find these a bit scary, or perhaps "artificial". Highly processed images can start to look unnatural by introducing digital artifacts. When used in appropriate ways however, these methods can correct for many ills of the original picture and bring out details that would otherwise not be possible.

I make a distinction in using these methods for the whole picture (globally) versus local applications of them.

Retouching or enhancing individual objects or areas in the image

Applying sophisticated methods to localized areas or objects in a scene is the border between capturing a view of an objective reality, and providing editorial emphasis on part of it. This is the point in the scale where artistic license is invoked.

Repositioning objects

Here we have definitely crossed over into altering the geometric reality of a scene. It is easy to do this using modern digital methods without it looking obvious. The main purpose is to enhance the compositional appearance or focus of a scene.

Superposing separate images

A common example of this is to place a subject in front of a different background. Since it is not possible to properly expose the full moon within a nightlit scene, separate pictures, each with correct exposure, are frequently combined.

Painting in objects that didn't exist in the original scene.

For adding artistic or informational elements. Usually they are obvious, but it is not difficult for a skilled artist to make them look natural.

Digital painting, inspired by, or using elements of an original photograph.

This is the gateway to a different branch of art.