Technical Info

Overview

The content of these pages will provide some definitions of the technical terms used in the Colour Index™ as well as information on chemical and application classes of dyes. Where this information is historically correct but awaiting updating to fully reflect current understanding and practice this will be highlighted.

Data Supplied by Manufacturers

The information on commercial colorants, and on their manufacturers and suppliers, contained in this publication has been provided by the companies themselves. In providing data for inclusion the supplier has signed a declaration stating that he has direct access to full test and safety data produced for the product he is selling. The user is advised to contact the supplier for this information and to verify for himself the position on regulation for the relevant country of import.

Main Application

To assist in searching, manufacturers and suppliers are asked to indicate main application areas recommended for their respective products. These are:

• Apparel
• Automotive fabrics
• Carpets
• Food
• Furnishings
• Knitwear
• Leather
• Microfibres
• Other
• Paint
• Paper and board
• Printing inks
• Swimwear
• Woven fabric

Uses and Comments

This is a free-text section of each product record that a manufacturer or supplier can use to indicate some of the principal features and/or uses of the product concerned. It is searchable.

Because this information is provided directly from the manufacturer or supplier, a wide range of search terms entered in this field can be expected to produce useful results. One of the four main application areas listed is 'Other': some of the more common terms for products thus classified that are adopted by manufacturers include:

Where information has been provided by a member company of the Color Pigment Manufacturers' Association Inc. (CPMA) via the Association, this fact is recorded.

Physical Forms of Products

To assist in searching, manufacturers and suppliers are asked to indicate the physical form in which their products are supplied. These are:

• Powder
• Presscake
• Granule
• Chip or flake
• Liquid dispersion
• Liquid
• Paste
• Flush colour

Product Status

Hue Indication Chart

The most important property of any colourant is its hue on a given substrate. The colourants in each usage section have therefore been subdivided into the hue groups conventionally used in the literature: yellow, orange, red, violet, blue, green, brown and black in that order, with the addition of white and metals to the pigments section.

The commercial name under which a colourant is marketed does not necessarily give a precise indication of its hue. This is well illustrated by the wide divergence that frequently occurs between the commercial names used by different manufacturers for the same colourant.

To overcome these inconsistencies and to introduce some measure of standardisation a hue indication chart, in the shape of a hexagon, gives prominence to the six major divisions of alternate primary and secondary hues, and at the same time provides continuity.

Each sector of the hexagon is divided into three parts, e.g. the yellow is divided into yellow itself, greenish yellow and reddish yellow.

The tertiary hues are situated inside the area of the primary and secondary hues, and in association with the parent hues. With the chart there is an outline diagram that bears the formal descriptions associated with the individual chromatic areas, each of which is designated by an outline which functions as a line of demarcation between the different areas. There is no qualification in respect to the hues being dull or bright as this can be affected by the substrate to which the colorant is applied and this is to be used only as an indication. The hues given in the Colour Index™ have all been determined by use of this chart.

The diagram below gives both users and registrants an approximate indication of the hues concerned.

To use this the colour palette of the computer should be set to more than 256 colours. The calibration of the monitor used will also affect the colours displayed, so it is important to understand that the colours included are approximate and should be used as a guide only.

Download the chart in PDF format or click the image below to see a full size version.

CAS and EU (EINECS/ELINCS) numbers

The Colour Index is increasingly being used for legislation and here, especially in the USA, there is a need for CAS numbers as cross references. But it is not always that a specific chemical has only one CAS number and, especially in the field of solvent dyes, there are cases where a substance can be found under several different CAS numbers, depending whether the chemical was announced to Chemical Abstracts under its full chemical name or quite separately under, perhaps, its C.I. Generic Name. Thus, for example, CAS number 12226-96-9 refers to C.I. Solvent Yellow 43, whereas 19125-99-6 refers to its chemical name, 2-butyl-6-(butylamino)-1H-benz[de]isoquinoline-1,3(2H )-dione.

This proliferation of CAS numbers/names to describe the identical substance has come about as often as not during the preparation of country-specific chemical inventories when the full chemical name of certain solvent dyes was, for reasons of business confidentiality, not made available.

The CAS numbers given in this Colour Index are those that are easily obtained from data banks or have been provided to the Society of Dyers and Colourists during the colorant registration process in the Colour Index. The CAS numbers shown do not indicate that the colorant is listed in any particular country’s chemical inventory. They are included to provide an aid to performing searches on known inventories such as CAS. Similarly, the absence of an EINECS number should not be interpreted that the substance is not listed in EINECS. Neither should it be forgotten that the regulations for ELINCS substances differ from those for EINECS substances.

 Likewise, before a product is listed in this edition, we have sought an assurance from the supplier that a safety data sheet is available, not merely copied from another product. Details of the assumed synthesis and information on patents and other information have been omitted. For some older products such details are included in the Third Edition, and this information remains available for reference.