Back in 2012 I made a mistake. I wanted to change the art world by introducing Yellowism – an autonomous phenomenon in contemporary visual culture – to the people. But defacing Mark Rothko's Black on Maroon at the Tate Modern was not the right way of going about it.

First, it was wrong to deface the work of a fellow artist, more poignantly a piece by Rothko, whose work and ethos I greatly admire. In the words of Oscar Wilde, "Yet each man kills the thing he loves." I didn't single out Rothko to make my statement; I would have done the same had the artist been Damien Hirst or Tracey Emin. It was a spontaneous decision and nothing personal.

Second, my actions were wrong because they served not only to heap ridicule upon myself, but also to turn the public against Yellowism. It doesn't matter how important one believes one's ideas to be, nor how genuine one's intentions are, it is unacceptable to deface someone's property without permission. What I did was selfish. My act has hurt many art enthusiasts and I deeply regret it.

I spent a year and a half in prison, in which time the British public has paid huge restoration costs, and Yellowism has became associated with crime. While doing time I tried to be as constructive as possible, making drafts and notes on art, and studying British culture. After being released, I realised that as long as one's health is good, and one is able to live freely, the problems we face, big or small, are things that everyone has to go through and there is no need to sweat the small stuff.

Notwithstanding the negative repercussions of my actions, I believe I can use this valuable experience for good. For example, I think it is important to comment on the contemporary art world as it stands today, which to my mind isn't good.

Contemporary artists simply produce things which aren't creative in their essence or spirit. Every work is a duplicate of a previous piece. It's like dealing with exactly the same work only in different variations. The graphic designer Neville Brody once compared this condition to that of using the ingredients of different colours, shapes and sizes, where in fact real creativity is missing.

Our generation has become more productive but less effectual in the visual language that we use. Maybe because of the demands of the market, artists have lost genuine creativity. Where are the new art movements? Where lies the voices of visceral dissent and thirst for change? Art has become a business, which appears to serve only the needs of the art market. As a result the art world no longer has radical thinkers and polemicists willing to scythe new and different pathways. Everyone is playing safe.

Yellowism was established to confront this issue. I still believe that the concept of Yellowism is apposite, and for me, it is a tool that can bring about necessary change in visual culture. It shows that any intellectual or even emotional messages can be easily changed and reversed. Using very primitive and absurd examples of flattening all the meaning into a yellow colour, Yellowism shows in a very direct way that creativity in its pure form has completely vanished. That said, Yellowism cannot be used as an excuse to scribble on someone else's art.

From this whole farrago, I have gained a valuable experience and learned an expensive lesson. I offer my sincere apologies to the Rothko family, to art enthusiasts and to the British public. I am very glad that the restoration project has finished, and visitors can enjoy Rothko's masterpiece again.

• Vladimir Umanets is not receiving a fee for this piece