Tonal Ranges
As mentioned in the previous article, Ansel Adams introduced the famous ‘zone system’ to black and white photography. Also, we have seen that photographers try and get both extremes of gray (that is the colors black and white) in their print to make it look attractive. There are about 7 shades in between, the middle shade being ‘the middle gray’. The middle gray shade if often used to calculate the exposure, and in modern studios to compare and calculate white balance effects. More often than not, you will hear of the middle gray shade in reference to black and white photography.
These are the zones of Ansel Adams. If you notice, they are a gradual change from pitch black to paper white. As far as photography goes, one could look at that as totally underexposed to totally overexposed. Remember, you need to select the point in your landscape (or whatever subject you are photographing), from where you take your exposure. THIS point will appear as the middle gray in your image. If you want it to appear darker or lighter you need to under or over expose accordingly. Keep in mind that all other tones in the photograph would be equally affected from your exposure. If you have honed the skill of visualizing then this should be not very difficult. In any case you do get used to it over a period of time. So - when you are photographing a subject, you need to identify the middle gray or the center zone and take your exposure from that area in the scene/subject.
One cannot stress enough on this point - if you follow the camera’s (or hand held meter) meter reading, EVERY image will be similarly exposed. Let us illustrate this with a simple example. Take three cards of black, gray and white shade. Load black and white film into your camera (or shoot using the BW mode). Take meter reading from the different cards and expose accordingly. Every card will appear to be the middle gray in the three images. This is because, speaking in terms of reflected light readings 9which is what the camera does), the meter suggests (+) or (-) depending on the amount of light reflected back to it from the subject. A black subject will obviously reflect less light and that is why it compensates to make it appear the middle gray in your image. So, when you want a black object to appear the same shade in the image, you need to UNDEREXPOSE it adequately. Similarly when you wish for a white subject to appear white, you will need to OVEREXPOSE it accordingly.
Try experimenting with a variety of shades on black and white film (or mode) so as to make them appear the same shade/different shade as per your choice. Also, try and make the same object appear a darker or a lighter shade by controlling exposure. Soon you will begin to feel in control over the tonal range of your black and white photographs.
