Friday, February 3, 2012

Home On the (Tonal) Range

Greetings, volks. Welcome to Hohenfels Volks, THE place for our place! I hope you’re staying warm; this cold can be a killer.

Today we’re introducing a new concept. We’re going to discuss tonal range. Usually tonal range is a term used in monochrome photography. But it can also be used in color, with a slightly expanded meaning.

Tonal range in B&W photography refers to the range from darkest black to whitest white. This is a vague definition; so let’s get more detailed here.

First, tonal range is limited by 3 factors. The first is your camera or film, the second is your monitor in digital photography, and the third is the printer or paper selected.

A film or image sensor can have wide tonal range, allowing for many levels between zone transitions. Though it has a wide range, it may not be capable of recording more than a few ranges at a time, which gives it more contrast. If you remember, there are 11 zones and that we generally want to get the bulk of our image in zones 2 through 8, with our true blacks in zone 0 and whites in zone 10. Zones 0 and 10 have no tone or texture; therefore convey no usable information to the image. This means we should be placing our extremes in zones 1 and 9 if we want any kind of detail. Tonal range in this context allows for more gradual shift between the extremes of each zone. As in the image “A Shot in the Dark,” narrow tonal range can increase the visual impact of an image immensely. Wider tonal range can be flat and lacking in impact if consideration isn’t given to the ranges you want to emphasize. You can use a wide tonal range, while limiting most of your imagery to one end of that range for more impact.

In film, light is recorded on a strip of film and silver halides. Where the light hits, the silver halides are concentrated, creating a thicker negative. This is referred to as your density. The greater your density, the greater the light recorded. A film's tonal range often corresponds to its density. A wide range of densities in a shot means a wider tonal range.

Your monitor also has a limited tonal range. The more modern LCDs have an incredible range, perhaps more than your camera or film. This will have an impact on your presentation and editing when using different monitors. This is part of the reason for calibrations for monitors and printers. We won’t discuss that here beyond this.

Your printer and paper also are limiting factors. As with monitors, papers and in digital, inks have different tonal ranges. One type of paper may have a wider tonal range and be capable of allowing the entire range of your image to be printed beautifully. Another type may not. The same with printers and inks.

In color photography, tonal range refers to all the above, but is applied to each of the colors, Red, Green, and Blue. Each color may have a different tonal range, in each of the devices we’ve discussed. That’s why on most newer cameras, your histogram can either show RGB, luminance, or both. This allows you to see each color in relation to the other colors.

When displaying your final image, you choose your presentation format- monitor, CRT, print, and so on. Giving the output and its tonal range the right consideration can go a long way to creating what you visualize and making your vision a reality. When you wish to print an image out, it’s best to have a test print from the target printer to ensure your monitor matches, then your image can be edited to match and you’ll get a great print. The same goes with film and silver based paper printing. Match your film to the paper that will achieve the results you desire and your photos will be better for it.

Later, we’ll look at more about this subject. In future posts, we’ll examining individual influences on, and aspects of, your tonal range. I’m looking forward to you joining us on our journey through photography.

I hope you’ll be posting your photos for this week’s theme, and get your vote tallied for next week’s theme!

Don’t forget to post any of your images you’d like to see here at the Hohenfels Volks Facebook page. Of course, commenting on both Facebook and here is always appreciated, too! Don't foget, we're on Google+, too!

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