Your choice of photo paper and ink will determine the look, feel and durability of the prints you make.
There are powerful arguments for avoiding the cheapest paper and ink options. The ink must have the right viscosity for the type of printer you use, and the paper must have exactly the right level of absorbency to accept the ink and be able to prevent it from spreading. The paper must also be the right thickness for the printer’s feed-in system.
Dye or pigment?
The choice between dye and pigment inks is made when you select your printer. Each ink type has particular advantages, although the differences between them may be quite subtle. The table below compares the key features of dye and pigment inks.
|Resistance to airborne pollutants||Good||Best|
|Appearance on glossy paper||Best||Good|
|Appearance on matte paper||Good||Best|
|Resistance to bronzing||Slightly better||Good|
|Colour gamut||Slightly better||Good|
|Performance on ‘fine art’ papers||Mediocre||Best|
For prints that will be framed behind glass, it doesn’t really matter which type of ink/paper combination you choose because the glass will largely eliminate the differences in appearance between the two ink types. For prints that will be displayed uncovered, pigment inks will have greater lightfastness as a rule, although the prints should be treated with a protective spray to protect the image against dust and abrasion.
Lightfastness ratings give consumers a guide to the durability of certain products under ‘normal’ display conditions. The most reliable ratings come from Wilhelm Imaging Research.
Some of the results of tests conducted by Wilhelm Imaging Research, showing the effects of image fading with different ink/paper combinations. 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.)
The main factors affecting the stability of inkjet prints are the ink/paper combination and handling and storage conditions. Cheaper inks on cheap papers can suffer from differential colour fading caused by light and exposure to airborne chemicals.
Magenta dyes are particularly vulnerable to light fading and prints will become more cyan in colour as they fade. It’s evident when you display unprotected inkjet prints on the fridge door. Cyan dyes are affected by chemical contaminants like ozone.
Prints generally last longest in acid-free albums, with the next best options being framed behind glass or encapsulated in plastic (‘laminated’) to protect them against airborne pollutants. This is also a good way to protect traditional photos against light, dust and moisture – as well as fungal spores in tropical climates.
High quality inkjet papers are normally made from materials that are acid- and lignin-free. Most ‘fine art’ papers are made from cotton rag, which has stronger, longer fibres and contains no lignin. Papers containing cotton and linen fibres can last for hundreds of years.
Look for ‘archival’ papers that have been tested to ensure they are chemically stable and physically strong. Check for a reference to a standard such as AS 4003 – 1996 or ISO 9706.
Some of the logos that can help you to identify papers that are certified as ‘acid free’.
Papers surfaces range from glossy through to matte and include intermediate ‘lustre’, ‘semi-gloss’ and/or ‘pearl’ finishes. Each surface has characteristics that can complement different types of images.
Specialist manufacturers like Epson and Ilford provide a wide range of paper types, sizes and surfaces to choose from.
Dye-based inks produce their richest colours on glossy and lustre papers while pigment inks tend to work best on matte and fine art papers. The smooth, shiny surface of glossy photo paper makes details appear sharp and colours vivid. High-gloss (or super-gloss) is even shinier to emphasise these characteristics.
Unfortunately, prints on glossy media are vulnerable to fingermarking. They may also suffer from specular reflections (glare) under directional lighting.
Lustre papers also have a surface sheen, often with a subtle texture that works well for images with fine tonal gradations. They are less vulnerable to fingermarking and specular reflections, although not totally immune. Photo Black ink is normally used when printing on gloss and lustre media.
Matte paper is smooth and flat and immune to specular reflections, but really vivid colours can be difficult to reproduce. Some matte papers have slightly textured surfaces, while others are ultra-smooth. They provide excellent image quality and the longest overall print life on the market.
Inkjet printers can also print on media other than traditional paper. Canvas printing is popular and enthusiast and professional printers can produce fine results. Other options include OHT (overhead transparency) film, stickers, coated optical disks and transfer paper for putting images on fabric items like T-shirts, placemats and canvas bags. Special inks are not normally required for printing on these media.
Things to look out for
Glossy papers can suffer from ‘bronzing’ when prints are made with pigment inks. This indicates the ink is unevenly deposited and/or absorbed by the paper. Viewed from a shallow angle, bronzing produces a greenish bronze tone. The latest pigment inks have significantly reduced this problem.
Gloss differential is another issue affecting pigment prints on glossy media. It shows up as patches of visible difference in the surface of the prints in areas where little or no ink has been laid down. Some manufacturers provide ink sets that include a ‘gloss optimiser’ cartridge that lays down an even layer of resin across the entire surface of the print.
The area circled in red has had no ink laid down when the image was printed. With pigment inks, this area of paper will look different from the rest of the print, where ink has been deposited. This is known as ‘gloss differential’.
An alternative is to spray prints with a fast-drying protective spray (which will also help to preserve the image). The spray reduces the reflectivity of high-gloss paper, turning it into semi-gloss, so it’s not an ideal solution. The best option is to avoid using pigment inks on high-gloss media.
This diagram shows how two colours that appear identical under one type of lighting (daylight) can appear different under another type of lighting due to differences in the reflectance of the colours.
Metamerism occurs when two colours appear to match under one type of lighting but look quite different with another. It is caused by dissimilar wavelengths being reflected differently under different types of lighting. Papers containing optical brighteners are more susceptible to metamerism when viewed under lights containing short wavelengths, which cause some papers to fluoresce.
Optical brightener additives (or OBAs) are widely used to make products appear whiter and are common additives in laundry detergents. They work by absorbing light from the invisible ultra-violet (UV) end of the spectrum and re-emitting it in the visible blue/white range.
This diagram shows how optical brighteners work by absorbing light in the UV band and re-emitting it as fluorescence in the visible blue light band. This makes normally buff-coloured paper appear white.
In papers containing OBAs, the reflected light from the brighteners overwhelms the paper’s natural pale beige colour. Because they rely for their effect on UV light, OBAs work best under light sources containing a lot of UV, such as sunlight and fluorescent lighting.
Papers with OBAs are often preferred for landscape and architectural photographs because they boost the colour gamut and black density of the printed image. Prints of portraits often look better on papers without them because the natural buff tone tends to soften colours and contrast and produce more attractive skin tones.
OBAs decompose over time causing the paper substrate to revert to its normal pale buff colour. You may be able to avoid this issue with over-coats that reduce the UV activation of OBAs, but their effectiveness has still to be proven.
Identifying the printing surface
Because a special coating is required to accept the ink, inkjet papers can normally be printed on only one side, although some manufacturers produce double-sided papers. There are two ways to tell which side to print on so you can load paper correctly.
It’s not a problem with papers that have the manufacturer’s name (or some other identifier) printed on the rear surface. With most matte papers, choosing the whiter side of the paper is a good strategy. For glossy and semi-gloss papers, touch a corner with a slightly moistened finger (NOT wet). The coated surface should feel slightly sticky.
Calculating ink costs isn’t easy because printer manufacturers base the figures provided in their specifications on the ISO/IEC 24734 standard, which reflects typical office printing, not photo printing (which uses more ink). By weighing ink cartridges before loading them and after they were depleted, we’ve been able to calculate the amount of ink each holds and work out how much ink is required to cover a specified area of paper.
Naturally, the amount of ink used will depend on whether the print contains mainly dark tones or mainly light tones – or a balance of both. For the latter, we estimate between 0.5 and 0.6 ml of ink is required to produce an A4 print with narrow white borders. Readers can use this figure with reasonable confidence when calculating their printing costs.
Paper costs are easy to calculate since paper is sold in sheets of specified sizes. When calculating usage, allow for a page or two dedicated to test strips and/or accidental mis-feeds or misprints.
Article by Margaret Brown
Excerpt from Photo Printing pocket guide