It's a painstaking process.

Scaffolding must be erected and taken down each night and cannot be attached to the walls to avoid damaging the paintings.

One of the biggest problems of the Sistine Chapel is humidity.

25,000 visitors a day pose a risk for the paintings.

You know our bodies are made of water, so when we visit the system chapel, we bring in humidity and we hit.

Everybody hit the environment like a bulb.

You say 80 watt bulb humidity causes condensation and a veil of salt forms on the famous frescoes painted in the 14 and 15 hundreds, which damages the color and the plaster it's painted on.

A laborious technique brushing distilled water onto thin Japanese paper removes the salt layer to combat humidity.

There are 30 hidden sensors measuring temperature, air circulation and number of visitors in the chapel.

Dr.

Victoria Tamino, the Vatican's conservationist monitors the air quality in the chapel through the temperature must be between 22 to 24 degrees Celsius.

Humidity must be medium high.

They are very precise markers, and we have to verify that the system respects them.

The frescoes in this chapel are over 500 years old now.

Back then, there was no artificial lighting.

The only light that came in was daylight through these upper windows and, of course, being the pope's private chapel.

Far fewer people came through here as well, so cleaning and restoration wasn't really a priority then.

Today, with new technology and lighting, not only is there better cleaning, but it has revealed to restores the original colors used by Michelangelo.

The world was shocked after a cleaning and restoration in the nineties to discover that Michelangelo actually used vivid greens, purples and reds because for centuries it was assumed that he painted in dark, subdued tones.

But that was on Lee the accumulation of dirt and grind.

The next time you're in the Sistine Chapel, look out for this little black marks, squares and triangles on some of the paintings they're called witnesses.

Deliberately left is evidence for future restores to give an idea of just how dark the paintings were before.

To make sure the color stay vibrant, a color team measures any changes to tone by taking pictures of the frescoes with a multi wavelength camera, which is then analyzed by a computer.

Dr Fabio Morrissey is in charge of color analysis.

Waken see the color of every single pixel and compare it throughout the years.

It's important because we can detect any changes even before they are visible to the human eye.

A behind the scenes labor of love so that the past may continue to brighten our future.

Delia Gallagher, CNN Round.