Little knowledge 丨 How fast textile color is rated? The average person I don't tell him

About the color fastness rating

Little knowledge. NO199 ┃ Learn a little every day

The color fastness results in two parts: one is stained and the other is discoloration.

Staining is to see how much color the sample is attached to the lining cloth, or how much color the lining cloth has changed.

Discoloration is how much color the sample itself changes. The results of different lining and rating methods will also be different.

In the correct use of GB251-1995 to evaluate the stain with a gray card at the same time, in the mind must retain the standard paste fabric without staining its inherent color characteristics.

For example, polyester linings are relatively bright and glossy. Adhesive liner is reddish and slightly dark. The cotton lining is not as bright as the polyester lining and has no obvious luster. Wool is yellowish and slightly less shiny. This is more conducive to a clear and accurate judgment of the degree of staining of the lining fabric after the test. However, it should be noted that the same lining fabric may have slightly different shades depending on the batch. If you fail to pay attention to the above issues, you may develop poor ratings, leading to errors in the assessment results.

1 , the use of gray card.

The GB250-1995 graded gray sample card and the GB251-1995 graded grey sample card were all five grade nine. There is no less than half of the provisions of the general observation of the sample when using the light source and the sample surface is about 45 degrees, the observation direction is close to the surface of the sample.

2. The effect of the cleanness and actual state of the grey card on the accuracy and stability of the assessment results.

The degree of cleanliness and actual state of the grey card is very important for obtaining accurate and consistent test results. When using the gray card, the tester should not touch the nine pairs of grey/white small cards in the sample card. If the small card is found to be fluffed, scratched, damaged, or stained with water stains, stains, grease stains, stains, perspiration, stop using. When the sample card is distorted, curled, or uneven, it should be stopped. In addition, the gray card will change during storage or use. The chroma data of each stage of each level will deviate from the standard range, and regular checks and replacements should be paid attention to. Otherwise it will affect the accuracy and stability of the assessment results.

3. The effect of the evaluation order on the rating results.

The color fastness tester is required to evaluate large batches of samples in a variety of colors on a daily basis, resulting in deviations in the ratings due to different color light stimuli. It is recommended to cultivate the scientific habit of using eyes and science, and select a certain rating order according to the color of the sample. If there are dark colors, light colors, orange colors, and red colors in the rating process, light color may be evaluated first, dark color may be evaluated later, and then the color may be further evaluated. Finally, the color may be red. In order to prevent the eye from being stimulated by colored light, the rating will produce errors. At the same time, after a critical level, it is better to compare each pair of the same grade and the sample again and re-evaluate once. This can make good judgments on whether the ratings are consistent. Any errors in ratings will be clearly contrasted at this time.

4. The effect of the lining method on the assessment results.

(1) All fabrics and yarns should be nailed to the original recording paper and covered with transparent tape at the tip of the nail on the back of the card for protection.

(2) Some areas use double-sided tape for pasting, but the use of double-sided tape when the fabric is attached may cause the fabric to fade.

(3) Trim: Trim the sides of the sample and leave a large enough piece for rating. Staple the sample on the card, making sure that the nail is parallel to the short side of the sample and as close as possible to the edge. Cut a piece of untested fabric of the same size and pinned to the card adjacent to the sample. There should be no overlap between the two and no gaps between the two.

When rating, make sure of the following:

a ) Make sure the sample and the unpatterned texture are in the same direction (some warp-knitted fabrics may not be very visible).

b ) As close as possible to the different colors of the multicolored fabric. For example: striped fabrics, stripes, and color sequences must be in the same direction.

c ) Line, sewing thread: Samples and untested samples are rolled into a small bundle and pinned to the card.

d ) The sample is adjacent to the sample.

e ) Multi-fiber cloth: Trim the sides of the multi-fiber cloth to leave as large a piece of adjacent test sample as possible on the card. Make sure the stained side is facing up and the staples are pinned to the edges parallel to the short side.

f ) The cotton cloth used for the frictional color fastness test: The edge of the cotton cloth to be tested is trimmed neatly, because the staining color rating is compared with that of the surrounding cotton cloth, so the lining area should be as large as possible. In order to avoid poor results from sample wrinkling, the two sides of the cotton cloth must be attached to the white card so that the cloth has slight tension.