# Capturing a Light ### 1. Prerequisites This function needs a spectrophotometer to work (Konica Minolta MYIRO, XRite Eye One Pro 1, 2 or 3) {% tabs %} {% tab title="Booth" %} ![](/files/-LjCd7c8rcQdm_sxPFsO) {% endtab %} {% tab title="Room" %} ![](/files/-LmofTkvXFPoBw20MPny) {% endtab %} {% endtabs %} ### 2. How to use Illum Reader Click on the icon "Create Light" in the toolbar of Coraye ![](/files/-MF59Nj5vmbpARxsQbsi) Make sure your spectrophotometer is connected. When the "Read target" window appears, click on "I'm ready". ![](/files/-MF5A2En54cgJDpYBZq_) A new window will appear to calibrate your spectrophotometer. ![](/files/-MF5ALd_OBGWYGvJ9eQy) Put the spectrophotometer into the calibration position\ Then click on the Start calibration button. {% tabs %} {% tab title="Konica Minolta MYIRO" %} ![](/files/-MF1kORVlnT-Mcw_W-wL) {% endtab %} {% tab title="XRite I1 Pro" %} ![Calibration position](/files/-LjCdWIXz4eH5y4Pt3QC) {% endtab %} {% tab title="XRite I1 Pro 2" %} ![](/files/-MBmacetMFAnXH6pkv2I) Then click on the **Start calibration** button. {% endtab %} {% tab title="XRite I1 Pro 3" %} ![](/files/-MF1l1t-XToZ7Cg0JqwT) {% endtab %} {% endtabs %} When the calibration is done, a new window will appear. ![](/files/-MF5KbWNUT3V0f2WmV3p) {% hint style="warning" %} Be aware, you have to use the cap to read the light with the Konica Minolta MYIRO, I1 Pro 1, 2 & 3. {% endhint %} {% tabs %} {% tab title="Konica Minolta MYIRO" %} ![](/files/-MF5JxL5wux6VaaJk7EE) {% endtab %} {% tab title="XRite I1 Pro" %} ![](/files/-LmoXixsOSnDVKRd4zzK) {% endtab %} {% tab title="XRite I1 Pro 2" %} ![](/files/-LmoY3NNcXpfsmb5HDiP) {% endtab %} {% tab title="XRite I1 Pro 3" %} ![](/files/-MF5Jkh5c4fFMGprSj3l) {% endtab %} {% endtabs %} To capture the light, it is now sufficient to measure directly with the spectrophotometer. \ Successive measurements will be displayed one below the other. ![](/files/-MF5IrbJW0ts_Id72sk1) You can make multiple measurements and rename them as you like. ![](/files/-MF5Ms_MKdCkxsgcviCq) When your measurements are finished, click on **Save and quit**.\ Yours lights samples will be add into the left column. ![](/files/-MF5NDRrB-j0wuPC7UdL) ### 3. How to manage yours Lights samples Click right on the color to **Rename**, **Duplicate** and **Delete**.\ **Export** option allow saving the color as a .sp file with spectral data.\ These .sp files are useful to share and backup yours light samples. ![](/files/-MF5Ojgl4w_j1Ww7aUs8) Measures can be export as a .sp file, to be saved on your hard drive. ### 4. What are the values associated with the measured sample? When we read a light, we can get information like [CCT, CRI, ](https://en.wikipedia.org/wiki/Color_temperature)Ra, Brithness, Lab and x,y ![](/files/-MF5TQO5IvFcXzSwcr-w) {% hint style="info" %} The [CIE](https://en.wikipedia.org/wiki/International_Commission_on_Illumination) [color rendering index](https://en.wikipedia.org/wiki/Color_rendering_index) (**CRI**) is a method to determine how well a light source's illumination of eight sample patches compares to the illumination provided by a reference source. Cited together, the CRI and CCT give a numerical estimate of what reference (ideal) light source best approximates a particular artificial light, and what the difference is.\ \ **CRI is a quality index for evaluating an illuminant. It is expressed as a percentage. the higher the value, the better the quality of the illuminant.** {% endhint %} {% hint style="info" %} The **color temperature** of a light source is the [temperature](https://en.wikipedia.org/wiki/Temperature) of an ideal [black-body radiator](https://en.wikipedia.org/wiki/Black-body_radiation) that radiates light of a color comparable to that of the light source. Color temperature is a characteristic of [visible light](https://en.wikipedia.org/wiki/Visible_light) that has important applications in [lighting](https://en.wikipedia.org/wiki/Lighting), [photography](https://en.wikipedia.org/wiki/Photography), [videography](https://en.wikipedia.org/wiki/Videography), [publishing](https://en.wikipedia.org/wiki/Publishing), [manufacturing](https://en.wikipedia.org/wiki/Manufacturing), [astrophysics](https://en.wikipedia.org/wiki/Astrophysics), [horticulture](https://en.wikipedia.org/wiki/Horticulture), and other fields. In practice, color temperature is meaningful only for light sources that do in fact correspond somewhat closely to the radiation of some black body, i.e., light in a range going from red to orange to yellow to [white](https://en.wikipedia.org/wiki/White) to blueish white; it does not make sense to speak of the color temperature of, e.g., a green or a purple light. Color temperature is conventionally expressed in [kelvins](https://en.wikipedia.org/wiki/Kelvin), using the symbol K, a [unit of measure](https://en.wikipedia.org/wiki/Unit_of_measure) for absolute temperature. Color temperatures over 5000 K are called "cool colors" (bluish), while lower color temperatures (2700–3000 K) are called "warm colors" (yellowish). "Warm" in this context is an analogy to radiated heat flux of traditional [incandescent lighting](https://en.wikipedia.org/wiki/Incandescent_light) rather than temperature. The spectral peak of warm-coloured light is closer to infrared, and most natural warm-coloured light sources emit significant infrared radiation. The fact that "warm" lighting in this sense actually has a "cooler" color temperature often leads to confusion.[\[1\]](https://en.wikipedia.org/wiki/Color_temperature#cite_note-1) {% endhint %} ![](/files/-LmsIAQPj61iwyT_gosv) To save your measure, click right on the measured light into the left bar, and select **Export** to save as a .sp file.\ As you see, you can also Rename, Duplicate or Delete the file when you click left on it. ### 5. Control your booth or your viewing condition IllumReader can be useful to check uniformity, the color temperature and the light intensity into a booth, to check the conditions for viewing proofs, objects and prints. \ \ In the field of graphic arts, ISO standards have been defined to standardize the visualization conditions of prints.\ \ Knowing how to master one's light knows how to master one's color. {% tabs %} {% tab title="Viewing condition" %} ![](/files/-LmofTkvXFPoBw20MPny) {% endtab %} {% tab title="P1 Critical Comparison" %} ![Standard viewing condition ISO 3664: 2009 P1](/files/-LjCd7c8rcQdm_sxPFsO) {% endtab %} {% tab title="P2 Practical Appraisal" %} ![Standard viewing condition ISO 3664: 2009 P2](/files/-LmsW8Kgsb1hbe_FtuiP) {% endtab %} {% endtabs %} {% hint style="info" %} ISO 3664:2009 – VIEWING CONDITIONS\ \ **Light source**\ • Relative spectral power distribution must match CIE illuminant D50\ • UV energy must meet CIE illuminant D50 (correlates to M1 within ISO 13655)\ \ **Two levels of light intensity conditions**\ • P1 Critical Comparison: e.g. two prints: **illuminance 2000 ± 500 Lux**\ • P2 Practical Appraisal: less critical comparisons e.g. hardcopy to softproof: **500 ± 125 Lux** or exact illuminance adjustment of light booth to monitor \ \ **Further definitions**\ • **Homogenity (Control over 9 zones in your booth)**\ • Surrounding: neutral gray diffuse surface\ • Viewing angle to avoid glare {% endhint %} ### 6. Light measurement can be use to calculate an Icc profile. {% content-ref url="/pages/-LjRTIyoM9ZfJ\_hs62lH" %} [Create a profile from a standard reference](/printer-management/how-to-create-a-media-profile.md) {% endcontent-ref %} ### 7. Show yours reflectance curves in the Spectral Viewer. It could be useful to compare reflectance curves of your color sample with a spectral curve of a specific light to understand the metamerism effect. If you need to display the spectral curve of your measured light, you can use the [Spectral Viewer](https://docs.coraye.com/visualization-modules/spectral-viewer) {% content-ref url="/pages/-LjCcaw4PDRzF6X\_8gFT" %} [Spectral viewer](/visualization-modules/spectral-viewer.md) {% endcontent-ref %} --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. 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