Research and Analysis

Conservators at the NMAH use a variety of non-destructive techniques, such as ultraviolet (UV) light, microscopy, and X-Ray Fluorescence (XRF) spectroscopy to examine objects and identify materials.

Ultraviolet (UV) Light 

This affordable, non-destructive technique involves using light to examine an artifact. Materials fluoresce, or glow, different colors under UV light. Conservators use UV light to identify sizing, a protective substance used in paper and textiles; varnish applied to paintings or furniture; and fill material applied during a previous repair or restoration.

Conservators might also use UV light to verify that their current treatment is effective.

Read more about ultraviolet light and its use in conservation.


Painting from an engine panel shown in normal light (left) and ultraviolet light (right)
Painting from an engine panel shown in normal light (left) and ultraviolet light (right). The green fluorescence seen in the image to the right is a layer of varnish made from natural resin and applied to the surface of the painting.


Microscopy, the use of microscopes, allows conservators to examine small fragments of artifacts and look closely at surfaces. Conservators can examine corrosion and identify active flaking. Microscopy can also help conservators understand what objects are made of and how they were made. It provides information about the artifact without causing damage. This valuable information guides conservation treatment decisions and exhibit protocols.


Sequin of one of Dorothy's Ruby Slippers viewed under a Digital Microscope
Sequin on one of Dorothy's ruby slippers viewed under a digital microscope. In this image the translucent red coating is flaking.

X-Ray Florescence (XRF) Spectroscopy

XRF is primarily used in conservation to identify materials by detecting the elements present. It can be used to examine metals, paint colors or pigments, glass and glazes, and inks. Through XRF analysis, a conservator can discover information about the methods used to dye fabric, past treatments to rid an object of pests, or all of the different materials that went into creating each part of an object. XRF is a helpful tool, especially when combined with other methods, to positively identify materials. Knowing what materials make up an object helps the conservator choose the right treatment materials and methods.


Superman Daily comic strip original art, #1422 during XRF analysis
Superman Daily comic strip original art, #1422 during XRF analysis


A colorimeter measures color and light range. It is used in conservation to evaluate changes in colors over time. Data gained through colorimetry helps conservators make exhibition decisions. If a material is prone to fading, conservators will ensure that light levels are kept at a minimum and the artifact is not displayed for long periods of time.

Conservators use a colorimeter to measure fading of the dyes used on Benjamin Franklin's three-piece silk suit.