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Oct 18, 20223 min read

What does Lightfastness mean on a paint tube?

Lightfastness, LF, and Permanence



Lightfastness on a tube of paint indicates how well the color will resist fading or changing when exposed to light over time. It’s a measure of the pigment’s durability under sunlight or artificial light, which is crucial for preserving the vibrancy and original appearance of the artwork.


Lightfastness, often referred to as Permanence, refers to the ability of the paint pigment to resist gradual fading when exposed to light. Pigments that fade over time are often called fugitive colors.


If you have a favorite fugitive color like Alizarin Crimson, look for the words “new” or “permanent” in the color name, such as Permanent Alizarin Crimson. These are reformulated colors that are meant to be lightfast for that particular color.


There are certain lightfastness standards that you should look for when choosing paint.


ASTM International (American Society for Testing and Materials) classifies colors based on a test that simulates 100 years of gallery exposure.


Color samples are exposed to an accelerated dose of light energy equivalent to approximately 100 years of museum-lit conditions. This exposure is condensed and takes around 15 weeks to complete, depending on the testing methods used.


After the simulation, the color difference before and after is determined using a spectrophotometer and the difference units are calculated mathematically. Less than 4 units of color change gives a color the designation Lightfastness I. In practice, this means that a visual comparison of unexposed and exposed samples, would reveal barely any perceptible color change.




Here’s a breakdown of common lightfastness ratings:


  1. Excellent Lightfastness (I or LF I): The pigment is very resistant to fading and should maintain its color for many years under normal lighting conditions.

  2. Very Good Lightfastness (II or LF II): The pigment is fairly resistant to fading but may show minor changes after prolonged exposure to strong light.

  3. Moderate Lightfastness (III or LF III): The pigment may start to fade noticeably over time with exposure to light, and it’s generally not recommended for artwork that will be exposed to light for extended periods.


ASTM Permanence Standard

  • ATSM I = excellent lightfastness

  • ATSM II = very good lightfastness

  • ATSM III = not sufficiently lightfast

 

Typical Manufacturer's Standard

  **** or AA = Extremely Permanent Colors

  *** or A = durable colors.

  ** or B = Medium Lasting Colors.

  * or C = Fugitive Colors


If the paint tube shows nothing for Light-fastness, the paint may not have been tested for permanence.


When choosing paints, especially for artworks meant to last, look for a high lightfastness rating to ensure the colors will remain as vibrant as when they were applied.


Struggling to remember your color recipes?

Stop wasting time and paint trying to remember how to recreate a colour.


This notebook will save you time and prevent you from wasting paint

  • note the exact colors for each of your art works,

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  • keep all your inspirational images in one place for fast and easy reference.


This notebook helps you free your mind of details so you can concentrate on your creativity.

        


You can use these link depending on your location:



How to enlarge all your drawings to scale without doing any calculations

How to guide to enlarge your drawings to reproduce a subject on a canvas with precision, without knowing how to draw and without having to take out your calculator.


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