Testing Colour Uniformity in Uniforms as per ASTM D1729

Uniforms make us all one, which is also defined by the very terminology “Uni” means one and “Form” means “living”. Same colour, structure, shape and design clothes for all under one class in a school/ college or in a department/unit in an office develops the feeling of one team, one group and one class among people studying or working together. Uniforms irrespective of who is wearing the same deliver the same appearance making that person a part of others.

With such meaningful importance to uniforms, they must at any chance never have an inconsistency to their colour. As if that happens the entire meaning of uniform dissolves and can also lead to product rejection as well as losing the interest of a client over your manufacturing unit’s performance quality.

Importance of Colour Consistency in Uniform Manufacturing Units

If the colours of uniforms vary across different platforms, the manufacturer may lose out on brand recognition, which can eventually lead to will impact sales and present a disorganised and unprofessional image. Maintaining consistency in uniform colour can enormously give a boost to brand identification, and give a rise to sales and engagement.

Colour consistency is also important especially for uniform designers as the colour printed on fabric is likely weakened over time with washing, wearing, storage and endless use. A colour gap in the starting can lead to faster loosening of colour quality also, losses potential clients.

Why does the Uniform Colour appear different under various lighting conditions?

Fabric Colours can appear different under various lighting conditions that depend on the composition of the light source under which the fabric is seen. For instance, a blue-coloured uniform checked under the artificial light of a petrol pump or street light will look completely distinguished when checked under the morning sunlight. This happens due to a phenomenon known as - Metamerism.

In Metamerism, two distinct colours may look similar under one common light source condition, and one common colour may appear different under distinct light conditions.

When light is absorbed by a piece of uniform, and in case of poor colour quality only a particular part of the wavelengths reflects back from the uniform sample. When a human eye perceives the “colour” of the uniform, it is actually absorbing the reflected wavelengths. The mixture of wavelengths defines the colour absorbed by the human eye. This is the reason why the uniform sometimes appears to be in a different colour in the manufacturing unit and different on the retailer street.

How to ensure the colour quality of the uniform remains universal?

To ensure that the colour of your uniform produced remains the same for all is a thing to achieve by strict quality control. In addition to tests like colour fastness, resistance to tearing impact and scuffing, one must conduct a high-quality colour consistency check under international test standard ASTM D1729.

According to ASTM D1729, the user must test and evaluate the viewing standard of the sample. The colour and appearance of a fabric depend upon its geometrical structure, quantity, the spectral nature of the illumination and also the surrounding conditions. That is why if one needs to test the colour viewing standard, it must be conducted under a controlled area. The cabinet should be enclosed, not allowing outside illumination. The chamber must be equipped with internationally proclaimed standards light sources. Also, the sample placement is done at a specified angle.

Colour Matching Cabinet, is highly standardized equipment that allows testing the viewing standard of uniforms under recision based conditions. It is equipped with light sources like D 65 - Artificial daylight, TFL -Tungsten Filament, TL – 84 Light-Point of Sale, UVB Light-Ultra Violet, and CWF Light-Cool White Fluorescent. Uniforms tested under this illumination can let the user know if its colour quality remains the same or not.

Further, the chamber has an hour meter to keep a check on the test duration. A defined angle of viewing booth that is 45 Degree as per the standards. The viewing booth is made up of Wood or Steel that allows highly controlled and sealed conditions for testing.