Paper is vital to the image making process, it is the thing that the viewer holds in their hands when they look closely at a print. An appreciation of fine paper is an essential trait in a fine art printer or exhibition print maker.
Mike McNamee teaches exhibition printing at the Epson Print Academy and Photoshop technique for Aspect2i courses and seminar. He is also the editor of Professional Imagemaker magazine and before that Digital Photographer and Creative Imaging. Over the past decade he has tested almost every printer intended for the serious, enthusiast market, along with most wide format printers. For an ongoing series in Professional Imagemaker he has tested almost every inkjet paper that has been made, some of them on a multitude of printers. The tests now run into the thousands almost every one subject to rigorous statistic analysis of paper performance backed by exhibition size prints. In this article he gathers together the important features of what has be learned in the quest for the perfect image/printer/paper combination.
What is Paper?
While it is something we take for granted, paper is also something that many people know little about. It is made from a variety of materials depending on both cost and intended use. Acid free and rag papers are preferred by many image makers. These are made from fibres derived from cellulose rather than lignin. The cellulose can come from grasses such as esparto or from cotton. Scrap cloth is used to make rag paper (hence the name) one of the finest materials in use.
Art papers have a surface coating of china clay to give a smooth, non-absorbent finish. This keeps the inks close to the surface and hence more vibrant. The glossy art papers are made by callendering the surface with multiple passes through hot (steam heated), high-pressure rollers. Strangely, 'art papers' are not normally used for drawing and painting, they are used for quality art books and magazines, with the paper being optimised for ink-on-paper printing.
In recent times new materials have made an appearance as 'paper'. The classic one, known to photographers, is 'resin coated paper' such as Ilford Multigrade. Here plastic film is bonded each side of a paper carrier material and super coatings are applied to the top surface to hold the 'high tech' surface of a silver halide emulsion. This same substrate technology is often used for gloss and lustre inkjet papers today. In the same way that resin coated paper requires less washing because of the 'barrier' to chemicals provided by the polythene, the same philosophy may be used to prevent ink running away into the base paper in the inkjet printing process. Inkjet papers are characterised by the following parameters which combine to impart a particular feel or character to a paper:
1. The make-up of the underlying substrate in the body of the paper
2. The paper weight (how much a 1 metre square would weigh)
3. The thickness, also known as the caliper
4. The number and type of surface coating materials
5. The surface finish or texture and tone
With just these five parameters to play with it is amazing the individual characters that papers can take on. Many are similar to each other, but some are almost unique in character. Choosing a paper for a particular purpose is endlessly fascinating for those who care about such things!
The substrate for quality prints should always be classified as acid free and lignin free. The words 'archivally permanent' or 'museum grade' are often associated with the better papers. The actual substrate material is usually a rag-based, alpha cellulose or often a mixture of both. Alpha cellulose is usually stiffer than a rag paper and mixtures lie in between the two. Alpha cellulose maybe derived form various grasses, sugar canes or bamboo. For high-gloss finishes a plastic substrate backing a paper may be used to provide the additional sheen - this is true of many gloss, lustre and silk finishes.
Paper Weight and Caliper
These two parameters are related. Thicker papers tend to be heavier but not in every case. Weights of less than 160gsm are a little thin for exhibition, mounted work. When a paper reaches more than 300gsm it may require special handling to ensure that it runs smoothly through a printer and may even require the use of the board feeder should one be available. Weights of 500gsm are exceptional and such papers feel more like board products. The Fine Art Trade Guild demands a paper of more than 250gsm for limited edition printing and most quality products lie between 250 and 325gsm. The caliper or thickness varies with the density of the substrate but quality papers are usually between 250 and 450 microns
Textured papers are only normally used for painting, drawing, inkjet printing and letter press printing. When we use the term art paper we really mean fine art, that is paper intended for painting or creative imaging.
The texture or 'tooth' of the paper is a key element in imparting its feel. A size is usually applied to keep the inks or paints close to the surface. A traditional watercolour paper is often prepared for use by wetting and stretching it out to dry. Many of the quality art papers come off a mould machine rather than the Fourdrinier machine used to make huge rolls of paper in a continuous sheet. The mould machine makes rolls of paper but has a woolen felt that presses the mash of fibres against the drying rollers and imprints its own unique signature to the surface of the paper. As the felt wears the texture of the paper becomes less pronounced. There are only a small number of mould-making machines in the world so it is hardly surprising that many papers share the same base paper. The subsequent inkjet receptive coating has a great influence on the final result though.
The image reproduced here is from the Canson Infinity range of papers, some of the types approved for the Epson Digigraphie scheme. The glancing light macro shot illuminates the surface textures and goes some way to explaining why a narrative description is difficult – you really need to handle and see a paper for yourself.
© Mike McNamee