
IE-A: Yes, we have a loss. Well, we conservators are very
interested in, and you’ve spoken at length on this aspect, when you
referred to the conditions at the museum…
Ángel Santiago: Mhh hmm.
IE-A: …not only in the work you did in the conservation
laboratory directly on the objects, but also in the environment where
they’re presented. I wanted to ask you about any possible
recommendations you might have as to lighting, temperature, humidity,
not only when we exhibit them …
Ángel Santiago: But when they are stored.
IE-A: …when they are placed in storage.
Ángel Santiago: For example, here we have all the organic plant-based materials,
cloth, and others, whose surface can be damaged with strong lighting. It
can damage the cellulose and even destroy it. That’s why we sometimes
see curtains with very bright colors on the side where the sun doesn’t
hit. And on the other side, where the sun hits, the cloth fiber is
disintegrating and that’s due to the photochemical action of the light
on the object. The problem is that we talk about visible light and we
talk about the most offensive one within the range of light, the
ultraviolet light. And in extreme cases, infrared because infrared
produces heat. The ultraviolet is rays, way more penetrating that
activate the electrons they’re made of and decompose them in some way,
and that’s why it’s destroyed. That is why we get burned; our skin is
destroyed when exposed to the sun. But what happens? If lighting is
controlled – the object is illuminated as little as possible when there
are no visitors – the deterioration tends to slow down and the object
can be left for much longer. There are objects that require that they be
stored every so often and left in storage for a long time before
exhibiting them again. That happens a lot to paper fiber, paper
specifically, textiles, to every material made of cellulose. There is
wood that changes color when exposed to light. It gets darker or
lighter. Sometimes the artist says, “But, I didn’t use a wood of that
color,” and it was the light that made it fade. You also have to control
the humidity because many materials interact that don’t react to
humidity or light in the same way.
IE-A: In the same way. That is the challenge here, the diversity…
Ángel Santiago: It’s the diversity of materials.
IE-A: …within the same piece.
Ángel Santiago: For example, if I had to store metals, I have to store them in a
relative humidity of 20 % or less. Wood has to be stored in a higher
relative humidity, because it has water, which means 50%-55%-60%,
depending on where that wood came from. Nylon rope, for example, the
green one that has a stick in the middle, that central spear, that’s
nylon, that deteriorates with ultraviolet light, it degenerates and
changes color. I had one in the laboratory, that was a brilliant orange
color and now it’s white, with just fluorescent light. That’s another
thing, fluorescent light is more dangerous to artwork than incandescent
light. Incandescent light produces infrared, fluorescent light produces
ultraviolet. It produces the range of blues, while the other one
produces the reds. And you have to be careful how you illuminate the
object if it has different materials. That’s why, up to now, the one
that’s winning is the LED light because you can control its color
temperature depending on what you need in order to prevent damaging the
objects. We’ve been using it to illuminate objects since the 90’s, more
or less. Then you have the stalks, that are protected by polyurethane.
But polyurethane reacts to ultraviolet light and tends to oxidize. It
tends to turn brown, and when its useful life is over it begins to
flake, as if it were skin. You know, that’s something…