Inks, Papers and Other Media

The choice of ink is dictated by the printer you buy because each printer is designed for a specific ink set. Each printer manufacturer formulates inks to meet the needs of the print heads in printers in their range. In some cases there is a different set of inks for each individual printer; in others, one ink set can be used with several models in the range.
Buyers of snapshot printers must choose between two types: inkjet and dye-sublimation (also known as ‘thermal’ or ‘dye-sub’). Inkjet printers generally produce longer-lasting prints and are cheaper to run.

Matters are more complex when selecting A4 and larger printers because you may need to choose between dye and pigment inks. The majority of A4 printers use dye-based ink sets, while some A3+ printers use pigment inks. It can be helpful to understand the differences between them so you can decide whether it’s worth paying more for a printer that uses pigment inks.
What Type of Ink?
Different ink types have different characteristics that have changed over the years as manufacturers have sought to combine the most desirable features of dye and pigment types to satisfy a broad range of photographers. However, the type of ink a printer uses still has some bearing on the quality of the prints you can produce.

Dye inks are cheaper to manufacture and, being liquid, can be forced through finer nozzles than pigment inks. Because finer nozzles can be used in the print head, dye ink printers are capable of reproducing finer detail than pigment ink printers. But that’s only part of the story.

Because ink formulators have a wider range of colours to choose from, better quality dye ink sets can cover a wider colour range than pigment inks. They can also produce deeper, richer blacks and more vibrant colours, particularly on glossy papers.

Pigment inks contain millions of tiny solid particles of coloured pigment suspended in a liquid carrier medium. This alone makes them more difficult (and, therefore, expensive) to manufacture. In the early days of pigment ink technology, ink formulators also had a limited range of colours to choose from. But pigment inks were popular because they produced more light-stable prints.

Recent developments have almost eliminated the differences in colour range between the two ink types. Pigment particles have also become smaller, making pigment printers capable of matching the details in dye ink prints. In the early days of dye inks, they were very prone to fading, a characteristic still found in the cheap inks you buy from supermarkets and department stores. However, the latest dye ink sets can deliver prints that can resist fading for 60 years or more when framed behind glass. Prints made with pigment inks retain their fade resistance advantage, with typical lightfastness times in excess of 100 years for prints framed behind glass.

The illustration above shows the results of accelerated indoor light stability tests on different inkjet inks. The top line shows the results from inks produced by a reputable printer manufacturer. The second line shows the results from a set of refilled cartridges, while the third line shows the results from a cheap supermarket brand of ink cartridges. (Source: Wilhelm Imaging Research.)

So, which type of ink should you use? That will depend on which factors are your highest priorities. The table below compares the key features of the two ink types.

Ink Costs
Consumers often complain about the high cost of inkjet cartridges. It’s a complex issue that is often poorly understood by the average person-on-the-street. Essentially, the major element in the cost of an inkjet cartridge is the ink delivery mechanism, which must be engineered and manufactured to a high degree of precision. The actual cost of the ink is comparatively low so it makes little sense to compare it with, for example, perfume costs.

So why don’t manufacturers make larger ink cartridges?

One reason relates to the physical size of the printer. To support larger ink cartridges the print head must be larger and more robust. This adds size, weight – and additional production cost – to the printer and these costs must be passed on to purchasers.

Essentially, there’s a limit to how much the manufacturers can charge for ink cartridges. The cartridge market is very price-driven and because manufacturers have a fixed cost for producing the cartridge itself, the only flexibility they have is in the amount of ink they put in it. In the near future you should be able to buy standard and high-capacity cartridges for a much wider range of printers. The size of the print head and sturdiness of the printer’s construction will doubtless dictate which models will support the new cartridges.

The best way to evaluate ink costs is to compare how much it costs to produce prints in a range of sizes from snapshots up to poster size. Going on the printing costs we’ve assessed by reviewing a wide variety of printers, it is difficult for home-based printing to match the cost of the cheapest kiosk-based services at snapshot print size. However, once you move to A4 size and larger, it becomes much cheaper to print at home – regardless of the cost of the printer and media you use.

Paper Choices
Matching the paper to the ink set can also affect print quality and durability. The paper must have exactly the right level of absorbency to accept the ink but be able to prevent the ink from spreading. It should also have a surface texture and thickness that complements the image and suits the final use for the print.

All inkjet papers have coated surfaces that accept the ink (and it’s important to print on the coated side of the paper). Coatings give papers certain qualities, such as weight, flatness, surface texture and ink absorbency.

The three main paper types used for photoinkjet printing are largely defined by their surface coatings: swellable, porous (or microporous) and cotton rag. It’s important to understand the differences between them because some types of paper perform better with certain inks types and different paper types require different handling.

Swellable papers should only be used with dye-based inks. They typically have three layers, as shown in the diagram following.

Most glossy and semi-gloss papers are of the swellable type. With some ink/paper combinations, swellable inks may require extended drying times and are susceptible to smudging and water damage. They can also show fingerprints.

Porous papers are often referred to as ‘instant dry paper’ and tend to have matte or semi-matte surfaces. They work best with pigment inks because they are coated with microscopic inert particles that create cavities in the surface into which ink is deposited. These cavities prevent the ink from spreading and give prints a dry-to-the-touch feel. The diagram below shows the typical structure.

Cotton rag papers are generally used for ‘fine art’ printing because they provide excellent image quality and the longest overall print life on the market. Offered in a variety of surface textures and thicknesses, they are best suited to pigment-based inks.

Glossy or Matte?
Choosing between glossy and matte papers is largely a matter of taste. Some images look best on glossy papers while others are best on matte or semi-matte. As a general rule, dye-based inks produce their richest colours on glossy paper while pigment inks are at their richest on matte and fine art papers. However, if you plan to frame prints behind glass, the difference between glossy and matte prints is minimised and the prints usually look very similar when framed.

Paper Thickness
It’s important to match the thickness of the paper you print on to the end use for the print. Paper thickness is usually measured in grams per square metre, although some manufacturers provide measurements in millimetres. Photo printing papers should be at least 170 gsm in weight; preferably 190-250 gsm (0.25 mm). Heavier papers should be used for A3 and bigger enlargements that will be framed.

Unfortunately, some printers are unable to use heavy papers as their paper feed mechanisms are not robust enough to handle the weight and stiffness of thicker media. Some printers require heavier papers to be fed in through a special chute or slot and most can only accept one sheet of heavy paper at a time. Check your printer’s specifications to find the maximum paper weight it can handle.

Be cautious when buying lighter-weight papers, especially if they are very cheap. Thin, lightweight papers may not be totally opaque. This factor is particularly important when selecting double-sided paper for printing photo books as you need to be sure the image printed on the reverse side of the sheet does not show through and affect the picture on the front.
Opaque papers are also better for prints that will be framed or put into albums because they prevent backing colours from influencing the appearance of the print.

USEFUL URLs
Visit the following websites for free software downloads and/or additional information on the topic covered in this chapter:
www.photoreview.com.au/tips.
www.wilhelm-research.com for information on image permanence and the results of lightfastness tests on printers and printing media.
www.planetark.com.au for information on ink cartridge recycling.
This is an excerpt from Post Capture Pocket Guide.
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