Close-up: Howard Greenberg is one of the most influential people in contemporary photography. For the past 40 years, he has been the owner and manager of the eponymous New York art gallery, a true trendsetter in art circles. His archives keep photos by some of the greatest 20th-century photographers. Greenberg started his career as a photographer before finally opening his first art gallery, which also had a school. Today, he is known to make some of the most accurate appraisals of a work's market value, which is why he is in high demand among experts and artists from across the world. He visited Bulgaria recently to unveil the first exhibition of works by the legendary documentary photographer and one of the few leading female photographers in the past 50 years - Mary Ellen Mark.

- Mr Greenberg, recently you presented the first Bulgarian exhibition of works by one of the biggest names in documentary photography, Mary Ellen Mark. What was your selection criteria for the images and how long have you been working with her pieces?

- Actually, the director of the foundation organising the exhibition came to New York and picked out the shots himself. But he is very familiar with her work as his wife Gergana did a study on Mark and so knows more about her work than even I do. The material on show in Bulgaria is far from the entire Mark fund in the New York gallery. After all, we are talking about a 50-year-old career. I have been working with her photos for many years. She was a good friend of mine. The photographic community in New York is not that big, it was especially small when I was starting out years ago. I opened my first gallery in 1986 and she used to live 3-4 doors down the road. We became friends over the years. She even taught at the photography school I founded. Mary Ellen was a remarkable human being, extraordinary. She had a very clear idea of who she was, what she liked and what she wanted. Those qualities have made her what she is in photography - an artist with a crystal-clear vision.

- Which is the most significant photo in this exhibition?

- I think the two images of Tiny are very powerful because they contain a personal story. Mary Ellen befriended Tiny and helped her a lot together with her husband. The two pictures offer insight into their relationship. It may not be the most significant work, but it encapsulates a pretty important story, which makes it valuable.

- Which is the most expensive photo?

- Prices are a relative thing - they depend on the print's size, whether they have been signed by the photographer. Mary Ellen signed very few photos and some of them are included in the exhibition. The prices of the photos in that exhibition range between $10,000 and $18,000.

- Do you have Mary Ellen Mark pieces in your private collection?

- No. My collection is composed primarily of photos made before the 1960s. I pick the copies mainly by their quality as prints and Mary Ellen never made her own prints.

- What are the most expensive items in your personal collection?

- I personally own about 450 photos, which is nothing compared to the gallery's fund of about 30,000. The artists are divided into price categories, broadly speaking. There are some extraordinary shots by illustrious names worth hundreds of thousands of euros, and then there are equally brilliant shots by talented photographers that cost $5,000-$10,000. I have about 15 pieces with an estimated value between $1,000 and $5,000. Perhaps the most valuable one is a print by Paul Strand. Almost the exact same frame, with no major differences, was recently auctioned for $50,000. But most of my pictures cost between $1,000 and $2,000. Over the years, I have held in my hands many a great photos without having the means to buy them. The net worth of my collection today is a reflection of my 35 years in the business and the fact that I am successful, have money and am able to buy more and more photos, raising the quality of my gallery and the photos themselves as a result. But I have never looked at my personal collection as an investment.

- How did your love for photography start?

- It began when I picked up my first camera and took several pictures, which was a year after I graduated from college. I have never studied photography, but I was stricken by the first series of developed film and I just wanted to make more. I wanted to dig deep into the essence of the art form, and I learnt quickly just from observing other photos. I visited galleries, bought albums. A book by Mary Ellen was one of the first ones I bought. And I just became a photographer. I did not make a conscious decision to be one, photography made my choice for me.

- How did you become a collector and an art gallery owner?

- I moved to Woodstock in 1972, already making pictures at the time, and became a photojournalist for the local Woodstock Times and sold photos to the major national daily newspapers. Woodstock has a great history. It has an art gallery dating back to 1902, the second oldest in the US, I believe. Many famous and interesting people spend the summer there and some of them are excellent photographers. If memory serves me right, 3-4 years after I moved to live there I was part of the photography community founded by the best 20th century photographer Alfred Stieglitz. Woodstock turned out to be closely linked to the history of photography. It was in that period that I decided to establish my own gallery that doubled as a school. Soon after, I realised that the art gallery is my calling. I found myself more interested in history than taking pictures myself. I fell in love with the idea of unearthing valuable shots, keeping stories, hidden gems. This is how I created my first art gallery - Photo Find Gallery, which was opened only in the warm six months of the year. The rest of the time I was on the road, rummaging through endless boxes of photos in photo studios and meeting people while visiting museums.

- Do you see yourself as a trendsetter?

- Unfortunately, I do not have a crystal ball so I cannot predict what will be valuable in the future and what not. What I can do is use my knowledge of history, the market, and the customers' profiles. In other words, I can make an educated guess on the success of a sale, and I can explain to people my reasoning, but you never know for sure what will happen. Everything changes - people's opinions, tastes and perceptions.

- Can photography be considered art? After all, it is only 200 years old and nowadays it seems that everyone takes photos.

- Yes, anyone can take a picture. But a photographer cannot be considered a master based on 2-3 photos. They have to make many photos over time, show if their images communicate, what they say, what the artist's underlying message is and if they speak a universal language. Why do you think there are artists whose works are instantly recognisable? If a photographer is good enough to take good shots, make albums over an extended period of time, to create iconic photos that are printed over and over again and that people still want to look at, then they can be considered a master. This does not happen by accident, or in a blink of an eye. Granted, some are good from the jump. Such an example is Mary Ellen, which gained wide popularity in the US at the age of 26. There is high quality in her early pictures, and it was obvious that she would have a great career. But she also continued to evolve and become increasingly recognisable, and the appetite for her work mounted.