dimanche 5 décembre 2004

Colour Filters For Coloured Images Most photographers, myself included, own a basic set of filters which hardly ever see the light of day. Is it because when we screw a yellow or red filter onto the lens to add contrast to a scene in monochrome photography we don't know what the final effect will be? Or is it that the pale filters seem to have too little effect... and the strong ones are too overpowering? Is that why these filters are usually relegated to the bottom of our gadget bags? However, don't despair... read on and keep those "coloured" black-and-white filters ready to use with colour film instead. I know they weren't designed for this but the effects are much more predictable and can be quite stunning. If you start to think about colour images instead of monochrome tones and contrast then these filters come into their own. The reason why colour filters (misnamed really because they're intended for use with black-and-white film) are so confusing is that when one is on the lens you actually see a falsely coloured subject whilst you're trying to concentrate on how a black, white and grey tone image is going appear in print. It's a bit like having to wear a pair of red and green 3-D spectacles to read this page... possible, but rather a strain on the eyes and the brain. Try attaching a coloured filter to the lens, then point, focus and compose the scene... but before you shoot a picture think, "I'm shooting colour!" You've got to keep thinking about colour because that's what you're going to get... sometimes subtle or scintillating... other times groovy or maybe ghastly. That's the thing with pure colour in a photograph... it's immediate impact! The trouble with such a direct action is that not every subject can use or will benefit from this immediate impact in the same way, if at all. There's also the individual mood or feeling created by a single colour... the combination has to be just right. Colours can be divided into categories... warm and cool are two of them. They can also be divided into primaries and secondaries. Primary colours - and I think of them here as colours in a transparency or print and not as the additive colours of the spectrum which make up white light - are red, blue and yellow. The secondaries are orange, purple and green. As with any medium there are rules governing the use of these colours... and because rules are rules they're made to be broken. Used just as it is, colour can be a very powerful means of expression. The stronger it is the more powerful it feels emotionally. Conversely, pastel colours and tints are soft, gentle and often more feminine. But the strength of a colour doesn't just depend on its hue. It can be affected and altered photographically by the use of exposure control. For example over-exposure with reversal slide film produces washed-out pastel tints. At the other end of the scale under-exposure produces rich, deeply saturated, vibrant colours. These are stronger, aggressive and generally more masculine in feeling. So with any colour filter you can change the mood of your subject quite simply by over- or under-exposing to produce perhaps two or more very different interpretations of the theme. To change a subject's colour completely can dramatically alter its mood. Reds advance and electrify whilst blues recede and freeze. Oranges and greens can look truly awful unless they're used to create or stimulate the right sensation. For example a "pea-soup" fog can be artificially enhanced with the (very) careful use of a green filter whereas using a so-called "fog" filter will generally leave a lot to be desired. Here green forms a colour association with a well-known phrase and in that instance can (and I use the word "can" guardedly) work visually. There's really no limit to the combination and application of "pure colour" to everyday as well as to out-of-the-ordinary subjects. What may please my eye may have no effect, or even a very negative reaction, to you or another viewer. This is because the question of whether to add colour or not is subjective and will usually produce divided reactions. Whilst the mechanics of additive colour filtration are fairly simple the difficulty is in being actually brave enough to try it. I often experiment with one or two of the three black-and-white designated filters I keep in my bag (yellow, orange and red) on as wide a variety of normal subjects and scenes as I think fit. By under- and over-exposing each basic shot by a stop or two I usually end up with a few usable slides from a sheet which perhaps casual observers, or the processing lab staff if you don't have your own darkroom, would think of on first sight as a complete disaster! It's important to bracket exposures when trying this technique because not all exposure meters measure all colours of light accurately. Deep red filters are especially tricky to meter through and usually err on the side of under-exposure. If I'm in any doubt with a TTL meter I use it without a filter in place and add the filter's "compensation" factor to the indicated exposure. As well as yellow, orange and red - the most popular monochrome filters - I sometimes use the so-called "colour correction" filters to add slightly enhanced, although still false, colour to my subjects. By using the blue 80B artificial-light to daylight correction filter, but with daylight balanced film, I aim for an exaggerated blue cast to my transparencies... as with the Frosty Teazles. The paler blue 82 series filters, normally used for correcting the warm light of dawn and dusk to a more natural rendering, are suitable for making foggy or winter landscapes even chillier. And for a completely ethereal mood I use a deep blue #47 Fog filter which, although designed to cut through fog in black-and-white photography as some other filters do, gives a surprisingly more colourful and graphic impact when mismatched than when used correctly. There is virtually no limit to the colour you can add to a scene simply by attaching a colour filter to the front of the lens. The explosion of "effects" filters created and marketed by Monsieur Cokin here in France went a little crazy for a few years with designations such as Dream, Pop, Stellar, Andromeda and Pulsar to name a few. They are safe to ignore for serious photography (being more akin to Photoshop plug-in effects)... but if you multiply the number of colour filters by the number of subjects available it is easy to see that the total number of combinations for 'pure colour" are virtually unlimited. All you have to do to be different is reach into your gadget bag for those often bought but often forgotten round and rectangular pieces of coloured plastic and glass... you'll find the possibilities for interesting colour images are only limited by your imagination. My three examples were taken within 100 yards of each other on the route of the Malmesbury River Walk in Wiltshire. A Nikon and 20mm lens was used for the red filtered shot and Leica M4-2 or M4-P with 28mm Elmarit for the foggy orange and blue images. But it hardly matters what camera and lens used... it's the colour effect that's important! 8:09:41 PM    comment []