Friday, 16 May 2014

What is ...Cast Coated Paper?

What is ...Number 5
Regular followers of this blog will know that in the middle of the month, I publish a "What is ....? post. The article covers various aspects of paper, printing and finishing in greater depth. However, many of these subjects are complex, so these posts are only intended to be a brief introduction to the topic.
What is ...Cast Coated Paper?
'Cast Coated' papers and boards have an extremely high gloss, reflective surface on one side with an uncoated reverse (see below about 2 sided boards).
The coating formulation is a mix of china clay, satin white (calcium sulphate and alumina) and precipitated calcium carbonate (chalk) held together with binding agents such as latex - so basically the same coating as for all coated papers (matt/gloss/silk).
The high gloss result is due to the use of a chromium plated roller, heat and elongated drying line. The wet coating which is applied in the traditional manner, via a series of applicator rollers, is pressed against a highly finished chromium plated metal cylinder which is heated on the inside. As the coating film dries, it takes on the even, level glossy surface of the casting surface (ie the chrome plated roller).
The process used today has remained largely unchanged since the early 1950's when an American company called S.D Warren developed and then patented the process. In order to stimulate the market in other areas of the world, they 'licensed' the technology to paper manufacturers, including two in the UK: Star Paper Mill (Blackburn) in 1954 and Tullis Russell (Scotland) in 1989, plus various other paper mills in Europe.
Cast coated papers and boards are mainly used in labelling and the "luxury packaging" market. In the 1960's and 1970's, when glossy was seen as modern and luxurious, cast coated products were really big. The products had names such as Astralux, Chromolux, Lustrulux - (you probably get the common "lux" theme!) and luxury packaging for such brands as Chanel relished in the clean, sleek, modern look.
A development was the addition of pigments (colours) on the coating and self coloured boards with a colour one side and a white uncoated reverse became a highly desirable board for business cards and membership cards - back in the 1960/70/80's when colour printing was expensive and much printing was still letterpress, using a coloured board (especially a glossy one!) was a way of introducing colour, cost effectively into a black and white world! 
Further developments have included the additions of metallic colours and pearlescent colours. Also, two sided products (in white) are now available by 'pasting' two one sided boards together back to back.

You maybe thinking from the way I am writing this that cast coated papers and boards are a thing of the past, they most certainly are not! It's just that with the advent of film lamination (more commonly known as gloss lamination) a large part of the market for cast coated boards disappeared. Although it should be remembered that gloss lamination is a plastic based process and makes recycling, much, much harder. If you want to see a beautiful job produced on Astralux, you don't have to look any further than the Alexander McQueen project here:
Fenner paper is the UK stockists for the market leading Astralux range manufactured by Favini in Italy (although, as they say on the BBC "other brands are also available")

The range comes in 27 different shades and also includes a black board, reverse, with a shiny black coated front - very nice... 
Posted by Justin Hobson 16.05.2014 

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