Evaluating the artistic merit of a photograph can be approached from several different perspectives. You can assess an image on its technical merit, solely on its visceral impact or on technique and visual power. A familiarity with the history of photography and its different genres will also enable you to make an informed appraisal.
When assessing a photograph from a technical perspective, you must first consider the composition. Composition is a multifaceted concept involving a focal point, the rule of thirds, leading lines and the use of depth of field. To engage the viewer, every image must have a strong focal point; to create a sense of viewing tension, that focal point should be off-center. Avoid placing your focal point in the center of your shot by employing the rule of thirds. Mentally draw two equidistant vertical lines and two equidistant horizontal lines through your perspective picture. Photo Composition Articles notes, "The intersections of these imaginary lines suggest four options for placing the center of interest for good composition." A strong photo draws the viewer in and moves the eye through the entire shot. Leading lines help create that movement, making every inch of the photograph viable. Finally, depth of field can be used to strengthen the focal point by blurring out any distracting background objects. Every guideline does not have to be employed to create a dynamic image.
An image's exposure is critical. Ideally, the shot will have a broad tonal range including highlights, mid-range tones and dark areas. Additionally, the photographer should capture detail in the extreme light and dark spaces. To better understand exposure, take a look at the photographs of Ansel Adams.
Lighting can make or break a photograph. As the viewer, look for the soft, pure light of early morning or the golden tones of twilight. Unfortunately, mid-day light contributes to harsh shadows and flat colors. However, if the photographer's goal is to capture a gritty or urban feel, then the unflattering mid-day light might be desirable.
As with any piece of art, what is appealing is subjective. The same photo might strike one person as a masterpiece while another person might categorize the shot as a dud. Visceral impact is powerful. If you find an image is compelling, then trust your instincts.
The guidelines delineated for assessing the composition of a photograph may be applied to judging the effectiveness of any type of art.
Even if an image does not adhere to the guidelines noted above, it can still be very successful, as there are exceptions to every rule. For example, when shooting reflections, it is often effective to divide the photo directly down the middle. The top of the photo will display the actual subject, while the bottom captures the reflection. This recipe does not follow the rule of thirds, yet the shot can be extraordinary.