Produksi pakaian merupakan sebuah proses yang rumit di mana barang jadi merupakan campuran berbagai bahan. Warna yang cocok dengan semua bahan ini penting untuk memenuhi kebutuhan konsumen akhir.

Rantai pasokan terdiri dari berbagai tahapan yang berbeda dan sementara pakaian mungkin melewati pencocokan warna pada satu tahap sebaran, kemungkinan terdapat perbedaan warna yang diamati pada tahap yang lain. Hal ini bisa terjadi karena kondisi metamerisme.

Buletin tehnik ini akan menjelaskan bagaimana Anda dapat mengurangi efek metamerisme dengan menggunakan iluminan standar dan kabinet pencocokan warna untuk menilai warna.

Metamerism adalah penjelasan ilmiah dari fenomena warna yang umum di mana dua sampel warna yang ada dicocokkan di bawah satu sumber cahaya, kemudian tidak cocok lagi bila dilihat di bawah sumber cahaya lainnya. Metamerisme hanya bisa terjadi ketika membandingkan dua objek; warna dari dua objek cocok dalam satu set kondisi tetapi tidak dalam set kondisi lainnya.

Contoh Metamerisme

Faktor dalam metamerisme yang sering membingungkan adalah warna yang konstan / tidak konstan. The colour of an object will appear to vary depending on the light source which is used to illuminate it. For example, you park your Terang red car at the roadside in Siang hari. Darkness falls and although you would still say you have a red car it may well appear to be brown under sodium lighting. Fenomena ini dikenal sebagai warna yang tidak konstan.

Contoh Warna yang Tidak Konstan

Metamerism is the differing effects upon the colours of two objects when compared under various viewing conditions. Several Jenis-Jenis Metarisme exist:

• Illuminant Metamerism occurs when two objects match under a certain light source to a certain observer, but do not match under a different light source to the same observer
• Observer Metamerism is caused by a difference in colour vision between observers; it is highly subjective and cannot always be avoided. However by proper selection and training of colourists the risk can be reduced
• Geometric Metamerism can be controlled by viewing the samples at the same distance from the observer and at the same (45 degree) angle to the light source

Beberapa bagian berikut ini akan menjelaskan iluminan dimaksud.

The energy of the light source used by the observer to view products is the most important factor affecting their appearance and in assessing the effect of metamerism. The two major factors that influence what we see are:

1. Jumlah dan kualitas cahaya yang menerangi suatu objek
2. Warna latar belakang terhadap mana suatu objek dilihat

Pandangan visual yang akurat tergantung pada sumber cahaya yang merupakan sumber 'terkendali', di mana ciri-ciri dan kualitas warna ditetapkan seperti dalam kabinet pencocokan standar.

An illuminant is a theoretical source of visible light with a profile which is published. In general, the illuminant values are a measurement of the spectral energy distribution of an artificial temperature radiator that radiates heat with a specific colour at the defined temperatures of the light source, unit [K].

• Iluminan memiliki nilai standar yang tidak pernah berubah, sedangkan energi sumber cahaya dapat berubah
• Sebuah sumber cahaya merupakan penyebar penyinaran seperti lilin, lampu pijar tungsten dan siang hari alami, sedangkan iluminan merupakan gambaran teoritis sumber cahaya tersebut
• Semua sumber cahaya dapat ditentukan sebagai iluminan, tetapi tidak semua iluminan dapat diwujudkan secara fisik sebagai sumber cahaya

Note: CRI (Colour Rendering Index) is defined as the ability of the illuminant to render colours as they would appear under true Siang hari. An index of 100 represents a perfect simulation of Siang hari.

Varian Lampu Neon:

• CW – Standard Sejuk White
• WW – Standard Hangat White
• CWX – Deluxe Sejuk White
• WWX – Deluxe Warm White
• ES – Energy Saving
• HO – High Output

Suhu Warna is a method for describing certain colour characteristics of light sources. It is a reference number that quantifies the appearance of light. The terms ‘Hangat’ and ‘Sejuk’ in lighting refer to subjective experiences, such as a Hangat flame or a Sejuk winter sky.

Sumber Cahaya Sejuk dan Hangat

Light sources that have higher Suhu Warnas are 'Sejuk' light sources, while those that have lower Suhu Warnas are 'Hangat' light sources.

Aplikasi of Suhu Warna

The brightness of illumination affects the apparent purity of colours and the amount of detail visible in shadows. In general, the brighter the illumination, the more saturated colours appear and the greater the amount of detail that may be seen in shadow. The geometry of the illumination also affects the parent colour and contrasts of a product. Whether the illumination is coming from a small source or a large diffused one, the angle at which the light strikes the objects and angle of view all affect appearance.

A matching cabinet is the standard equipment for the visual assessment of colour and they are best used for colour appraisal with the below parameters:

Dimensions

Cabinet Interior

• The cabinet interior should be a neutral, grey colour e.g. Munsell Grey N5
• For best results, glare, extraneous lights and anything which will mal-adapt the visual response must be avoided
• Any windows near the cabinet should be fitted with grey blinds
• No direct lights should be in the field of view and the general lighting in the vicinity should be ‘Artificial Daylight’ to a level of 200 to 300 lux
• The wall area behind the cabinet should be finished in light grey emulsion e.g. BS00A01

Viewing Backgrounds

• The shade matching cabinet utilises neutral grey surroundings to accommodate the widest range of colours

Viewing Distance

• The distance of the Colour Matcher to the samples being viewed should also be constant regardless of the colour of the samples. The samples should ideally be viewed at a 45º angle of incidence to the light source.

We have seen that metamerism and illuminants are important considerations in controlling and assessing colour in the manufacturing process of any coloured object. In textiles it is therefore important to use consistent quality dyestuff and to consider and use the appropriate illuminants and conditions in matching colour.

Please contact your local Sales Office to find out more about metamerism and illuminants.