Every picture tells a story: Colin Prior on his landscape photography

Colin Prior is Scotland's top landscape photographer. But what's the secret to taking the perfect shot? Here, he speaks to Tim Cornwell about his life's passion and describes the stories behind some of the pictures that feature in his new book

• Beinn Dearg, Ullapool

SHOOTING definitive pictures of mountains, says Colin Prior, is like planning a military strike. The rules of engagement are the same in Bhutan or Pakistan as they are on his home turf in the Highlands and Islands, says the leading Scottish landscape photographer,

Stage one is reconnaissance – gathering information about the lie of the land, the best access to the chosen spot, and the level of risk. If he is ascending a Scottish summit in darkness, in preparation for a sunrise start, it is vital to know the likely weather conditions, and the level of snow or ice on the route.

Stage two is planning: deciding where to shoot from, the direction of view, when the best light will fall, and the best time of year. Stage three is logistics: checking and packing all necessary items of camping and photographic equipment. Prior's rucksack weighs in about 52lbs (24kg), including his camera, tripod, and the light one-man tent. Forgetting matches, a lighter, or a cable release is easily done but would be a crippling oversight should you be heading 3,000ft up to the top of a mountain, where you would be unable to heat food or water or shoot without camera shake.

"It's about gathering intelligence, from previous trips," he says. "It's about reading the weather, it's about preparation, ensuring that you've got the right equipment in your camera bag. It's eradicating the possibility of mistakes.

"Both sunrise and sunset are very good times, and the geography of the location will ultimately determine whether you are going to shoot at sunrise or sunset. My preference is always for sunrise because so often, particularly at this time of year when the temperatures start to dip in the evening, it's not uncommon that you've got mists."

• Buide Beinn, Loch Hourn

Catching the sunrise frequently involves overnight camping expeditions, and treks that begin in the darkness of the small hours to viewpoints or summits. But such painstaking preparations, says Prior "can still do no more than shift the odds in a photographer's favour".

The fourth and final stage in the perfect landscape shot is seizing the moment of "the strike" itself, when the light and weather may only be right for a matter of minutes. Ranging across "wild Scotland" for his new book, High Light, Prior used two kinds of cameras: the (now conventional) digital camera, and a panoramic camera that uses film. "The panoramas I continue to shoot with film because of the unique effect that can be achieved. The camera is a Fuji Professional GX 617 Panoramic. It's no longer made, they ceased production about four years ago. On one standard roll you've only got four exposures." In the critical 15 minutes or so of a shoot, the moment he has waited for, Prior may change the film seven or eight times.

• Old Man of Storr, Trotternish Ridge, Skye

Prior is at the summit of his profession. Born in Milngavie, Glasgow, in 1958, he became the operations manager of a welding technology firm, but switched careers after winning the best newcomer category in an underwater photography competition. He has series of books to his name and runs photography training courses tied to the Colin Prior Photography School he set up in 2006. He's talking to The Scotsman from Islay, where he has just watched a hen harrier chasing starlings with one teaching group. Next week he takes ten photographers on a course based in Ullapool, then heads to Bhutan with another group of seven. He now handles about ten courses a year. "Photography has become a pursuit and conduit for self-expression, and there's a great deal of people out there that are very keen."

Behind the successful shots are the stories of the mountains that got away. The cover shot of High Light is a picture of Blaven, one of Skye's 12 Munros, captured at dawn. The morning light colours the cloud, above a light snowfall that accentuates the black rock. But it took him three attempts before he got the picture; on the worst days his outings do not produce a single frame:

• Dun Beag and Dun Mor, Isle of Sanday

"You often find yourself in a location at a time when you think you might be successful. You will carry a heavy rucksack up to a mountain top in anticipation of shooting this image that's been in your mind's eye for three or four years.

"If the weather doesn't develop in the way you have anticipated, you have to go back. If you don't get the conditions to shoot that particular image, you may need to wait for the next year. It's determined by the position of the sun and the sky and that varies enormously between the two solstices.

"What I'm trying to get is a combination of a specific location, it might be a mountain, it might be a mountain range, but the most important aspect of it is to have the combination with great light. It's really about the light. A lot of people who are familiar with my photographs associate them with place, but they are never really about place, they are really about moment."..