The concept of authenticity is familiar from the world of music - musicians trying to perform a piece the way the composer intended it. Also of course from paintings  - is it a real Michelangelo or a fake ? The term is less often applied to photography because we tend to assume the camera doesn't lie. Well, maybe the camera doesn't lie, but photographers can.  There is plenty than can happen between the RAW file and the print. If you see a picture of Stonehenge with mountains in the background then you know the image is not authentic - Wiltshire is flat.  I won't dwell on this because I define this sort of thing as digital art and not photography. I am concerned with the more subtle issues for photographers who process their images for effect, but who want to retain the essential quality of photography - that is it real - and links us authentically to a time and place. We must have authenticity - but we have fidelity in degrees.

Let's look at some of these issues in practical examples. 

* if you move the mouse over the images below, the unedited version is shown *

This picture of the skater is obviously a favourite of mine, being used frequently on my home page. Simple images are often the most effective. I have cropped the top and left and brought the skater into the corner opposite the trees. More controversially, I have edited out the legs of the second skater. I stood for some time as the skaters circled round, trying to get the elegant one in the frame on her own. It was freezing cold that day and I couldn't wait much longer. Through the viewfinder I saw the subject was well placed, took the shot, and didn't pay much attention to the edges of the frame, until I got home and realised the shot looked a mess. The changes remove unwanted elements but they don't add anything artificial. You may also notice that the blues are different hues. I think the final image was processed with Canon's RAW converter whereas the original is from Adobe Camera Raw.

skater in Central Park


The second example is simply an auto-levels adjustment. This image was taken on a dull overcast winter's day in Canada. The original image ( see it by moving the mouse over the picture ) is probably an accurate recording of the subject. The adjusted image has substantially different color and contrast - now we have a dark grey-blue background that contrasts nicely with the brown teagles. I routinely make adjustments of that type and I don't agonise over it. But I acknowledge there is an issue here. If the blue background wasn't in the original scene, and is now a key element in the image, then is this really still a photograph ?



from RAW to print

To get some perspective on this, let's consider the RAW file that came out of the camera - that is the most authentic record a digital photographer has. A RAW file is the output from a device that measures light - for a 12-bit RAW file it's just a set of numbers from 0 to 4095. The device measured light levels at different points, through red, green and blue filters. Those numbers don't have any absolute significance. They are certainly no use on their own. They need to interpreted and adjusted for a number of reasons :

exposure - the level of brightness is a function of the scene you photographed and the exposure setting of the camera. You may decide that the camera over- or under-exposed the shot and adjust it accordingly.

tone curve - if you map the RAW file data proportionally onto an RGB value for your computer screen, you get something that doesn't look much like the original scene. This is because you have two devices here - the camera and the screen - and they relate light levels to numbers in different ways. You need a mapping to ensure that the input to the camera matches the output from the screen - that mapping is called a tone curve. It takes the general form of a S-curve but there are subtleties, not least because the curves can be different for each color channel.

color temperature - we adjust images for white balance. The camera is usually recording reflected light, and the color balance of the image depends on whether there was direct sunlight, cloud or artificial light. Now you might reasonably ask, that if the camera captures a scene with blue color balance in cloudy conditions, or a red balance in evening sunlight, isn't that just how it looked at the time ? Isn't that a faithful representation ? The answer to that, as to most questions in photography, is yes and no. Your eyes adjust to the lighting conditions after a while - they adjust to the color of incident light and to the overall light levels. So you don't really notice quite how red everything is in evening sunlight. If you capture that color with the camera, print the shot without any white-balance adjustment, and view the print in ordinary light, your eyes are not adjusted now, so the print looks like it has a red color cast. The purpose of the white balance adjustment is to remove the perceived color cast in the final print.

These processing techniques are necessary to achieve fidelity in the final print. However the same techniques can also be used to modify an image to increase its impact or artistic qualities, at the expense of fidelity.

drawing the line

Coming back to the teagles, I was talking about that blue background being artificial. However color is a relative concept. The background is blue relative to the teagles. The auto-levels adjustment does not invert the color and tone relationships in an image, it only stretches them. So I'm comfortable with this and regard the adjusted image as authentic. There are other image processing techniques that I employ regularly. For example perspective correction; changes to aspect ratio - stretching all or part of an image horizontally or vertically; and levels applied to selections. This last technique is especially important.

Churchyard at Long Melford, Suffolk

The next example is a photo taken in the churchyard at Long Melford in Suffolk. There are number of distinct changes made here ( move the mouse over the image to see the original ). First I have altered the balance between the sky and the rest of the image. A grey-grad filter would not have worked in this instance, I have drawn a selection around the stone figure - I want to keep the figure bright.  I have removed the intruding branches on the right, and reduced saturation a little - the sky is desaturated more than the ground. The reason for that last step is not obvious. Sometimes I feel a change in color representation is needed to get across the right atmosphere. Occasionally I may convert to black and white, but color is subtle and there are many possibilities. I sometimes edit images in stages over time. I will review changes at each stage to see if the picture is improving. The original conversion from RAW will get overwritten and I don't generally make a comparison back to the original to assess the total cumulative change made. In the case of the Long Melford image, I went back to the RAW file to compare and was quite surprised how different it looks.  I think there is a clear artistic purpose to what I have been doing. I had a view of the picture I wanted and set about achieving that with the RAW file as a starting point.

These examples have been chosen to show how far I take photo editing, and are not typical. I think I've stayed on the right side of the line and preserved the essential quality of the photographs as authentic records. But I'll keep trying to get perfect shots straight out of the camera. for photography