> For the complete documentation index, see [llms.txt](https://docs.coraye.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.coraye.com/visualization-modules/spectral-viewer.md).

# Spectral viewer

## 1. How to use Spectral Viewer

In a first time, we need to load or capture light samples, or color samples, to display their curves.

Capture them:

{% content-ref url="/pages/-LksZnucHvG5j25\_VkYE" %}
[Capturing a Light](/colors/capture-a-light.md)
{% endcontent-ref %}

{% content-ref url="/pages/-LjRWNUUBgIH4z82yR6v" %}
[Capturing a color](/colors/capture-a-color.md)
{% endcontent-ref %}

Or load a .sp (light sample) or .spc (color sample) file:

![](/files/-MExT6E6UrW7XZ8EyPHA)

![](/files/-MF-ttDguu3GDdmpaC5M)

Samples will be added in the left column.\
Into the main window of Coraye, click on the **Spectral Viewer** pictogram (the second icon on the top middle).

![](/files/-MF-uDQIad68_fKNmluz)

Then click on the small square at the right of the sample name.\
The spectral curve will be displayed 

Example: Fluo tube light.

![](/files/-MF-udBzmSrkFgLwB9Z1)

Example: Natural day light

![](/files/-MF-uy8vHGX2cgKXKEPq)

Spectral Viewer is also able to display reflectance curves for color samples.\
The color of the curve is the color corresponding to the color sample.

![](/files/-LmtK7ZRQ5q77T4VonVf)

### 2. Customize yours curves

![](/files/-MF-yZRV_C_yXfzGE20h)

### **3. Metamerism**

By comparing the reflectance curve of a measured color sample with the spectral curve of an illuminant, we can get an idea of what will be the influence of an illuminant on a colored sample. (Metamerism)\
You can also use the slider on the **scale** to compare the curves between them.

![](/files/-MF-z0EKzzuxAN76a0My)

{% hint style="info" %}
In colorimetry, **metamerism** is a perceived matching of colors with different (nonmatching) spectral power distributions. Colors that match this way are called **metamers**.
{% endhint %}

When you hover over the curves you get the values in mW / (m2.nm)

![](/files/-MF-zehtoMxi_dsUeNjU)