Light Fastness Tester

FED-O-METER

ð  All dyed material experience change in colour when exposed to daylight for a sufficiently long period because of the action of sunlight.

ð  The colour fastness is denoted by the number of the light fastness standard fabric that has change colour to the same extent as the test specimen.

ð  It is expressed as the numerical rating for light fastness.

Features of Fed – o – meter:

ð  An effective and essential fabric & garment testing equipment.

ð  It is used to determine the colour fastness and degradation of textiles to Sunlight.

ð  This Tester comes with a 500 watt MBTL lamp.

ð  Automatic voltage stabilizer.

ð  Stainless steel clamps.

ð  Gray scale for assessing change in colour & L-4 standard.

Specifications of Fed – o – meter:

Light Source	: 500W, Xenon arc Fading Lamp
Test Chamber Temperature	: Ambient to 50° C
Temperature Range Control	: By Water Circulation
Specimen size	: 100 x 50 mm
Power	: 220 Volts, single Phase, 50 HZ, A.C. Supply.
Power Consumption	: Maximum 1 KW.
Water	: Use of Distilled Water only in the water circulation Unit.
Recommended Ambient	: 20°-24°C Temperature
Operating Conditions	50%-65% Relative Humidity

Working

Stage: 1

ð  A strip of test specimen (50 × 10 mm) and one strip each of 1 to 8 light fastness standard (LFS) is mounted on the specimen card and the same type is put in the type ?A' rectangular cell. Along with double slot mask (1/3 area cover) 2/3 of the specimen is exposed to light.

ð  The effect of light is followed by inspecting the specimen frequently. When a change in colour of the exposed portion of the specimen can just be perceived, equal to gray scale grade 4-5, the number of the light fastness standard showing a similar change is noted.

ð  The exposure of the specimen and the LFS is continued until the contrast between the exposed and the unexposed portions of the specimen or the LFS no. 7 is equal to gray scale grade 4.

ð  If the LFS no.7 fades to a contrast equal to gray scale grade 4 before the specimen does, the exposure is terminated at this stage.

Stage 2:

ð If the specimen fades to a contrast equal to gray scale grade 4 before the LFS no.7  does, the double slot mask is taken out and the single slot mask is inserted having 2/3 area cover.

ð The exposure is continued until the contrast between the fully exposed and the unexposed portions of the specimen is equal to gray scale grade 3. The exposure is terminated at this stage. Assessment of light fastness is done.