How many dinosaurs does it take to change a light bulb?

Next week our dinosaurs will go to sleep for two weeks. The Geology exhibition will close for “essential maintenance” – you will have seen similar signs in other places. In our case “essential maintenance” does not mean that the dinosaurs’ toilet is blocked (now we do have coprolites on display but they are well and truly fossilised). But if you thought all the light bulbs were blown and we have to fit new ones you wouldn’t be far off. Except that we never did have any black holes in our galleries – no need to bring miners’ lamps which are absolutely reserved for Big Pit.

What we are going to do does indeed involve changing light bulbs. We need light in order to see, and without light we would not be able to appreciate most objects in museums. Light, however, can damage many types of objects. You may have noticed at home that old photographs fade, as do organic inks and pigments on prints and paintings. Leave a newspaper out on the window sill for a few days and it will have yellowed.

In the museum, where we preserve objects for posterity, the damage done by light can be a major problem. Any such damage is irreversible and cannot be repaired by our best conservators. Ultraviolet (UV) radiation is particularly damaging. How long do you think museum objects should last? As part of our collections care, we plan lighting in galleries carefully to leave colours bright and vivid for as long as possible.

The new lighting systems we are fitting this month at National Museum Cardiff will be more energy efficient. In addition, the new lights will be of better quality which means you will see objects more vibrantly yet safely, without causing unnecessary fading. Because the new lights also produce less heat they will make it easier and cheaper to air condition our galleries.

Changing the lights is not all we are going to do – there are a myriad of additional jobs to be done while we have the opportunity. All this takes a little time – between the 20^th June and 3^rd July. It won’t really be the dinosaurs changing their own lights, of course – there will be technicians, curators and conservators busily climbing ladders and scaffolding.

We do all we can to preserve our national collections and to improve our sustainability. So please bear with us when you see the signs and come back to see the Geology galleries in a new light in early July.

 Find out more about care of collections at Amgueddfa Cymru - National Museum Wales here.