More about print care

Printing Technque

General

Most of fine art photographs of today are print using inkjet printing technique, sometimes using fancier name gicl‚e. There are many different printers and inks available in the market. They differ in resolution, color, ability to render smooth tones and longevity.
For the best result, photographs are printed on special high quality inkjet paper. It uses natural acid-free base to ensure stability of the print. Surface of this paper is specially coated to absorb ink droplets not allowing them to spread thus maintaining high resolution.

Black and white printing

General color inks allow producing black and white prints that look acceptable to most people. However, there are two major difficulties. First, since grays are achieved by mixing multiple colors, it is very difficult to achieve truly monochrome prints across the whole spectrum. Very often different shades of gray have slightly different color tints. For example, shadows are bluish, while highlights yellowish. Color cast will slightly vary under different light source. Attentive observer may find it distractively unpleasant.
Another problem becomes evident with age. Different colors have different aging characteristics and the print is likely to develop more noticeable color casts. While certain tones like traditional warm or cold are OK, other colors (e.g. greenish or magenta) can be experienced as disturbing. Therefore many fine art black and white photographers use special inks. However, it is worth mentioning that color inks of major manufacturers are continuously improving in all aspects.
Dedicated monochrome inks are made from pigments of one color, usually gray. Sometimes they have small amount of blue and brown pigments to allow printing toned photographs from cold blue to sepia. Some inks use carbon pigment, which has slight warm tint. Carbon pigments are believed to be one of the most archival.

Archival Printing

This topic is widely discussed and there are many myths and misconceptions circulating among photographers and photo appreciators. Technically speaking, this can be quite complicated. Luckily, to enjoy our prints, we do not have to understand all scientific details. Knowing basic facts is often enough. For the sake of simplicity, we will discuss what it takes to make archival prints and how to maintain their archival qualities best.

Inks

Of all components affecting longevity of print, ink has the most influence. In the beginning of the inkjet era, prints used to start fading after a couple of years. Over the last years inks have improved drastically and best inks from major printer manufacturers are said to reach 100 years and more. However, as said before, black and white photographs printed with color inks exhibit color shifts when aging.
Various manufacturers have developed special archival inks. Most of these inks are based on pigments rather than dyes. For color prints, look at Epson Ultrachrome K3 inks. For black and white photographs, MIS Associates make a selection of inks for most of Epson and Canon printers. Note that not all inks are available for all printers.

Paper

Having selected good inks, let us take a close look at paper. Choice of paper is also very important. Unsuitable paper can ruin the best inks. Paper for archival photographs should have three qualities: be durable, acid-free and not contain materials that emit gases with aging. In other words, it should not deteriorate with age and not affect ink pigments. Best papers for are made from pure fiber pulp (completely natural). They are pH neutral and very stable. Look at FineArt papers of Hahnemuhle, Somerset Velvet papers, or Epson Matte paper. Ilford also makes several good papers.

Print Care

Light

Ultraviolet light causes all inks to fade. Direct sunlight is the biggest natural source of ultraviolet radiation. Ultraviolet radiation is also present in fluorescent and halogen light, but in much lesser amounts. Photographs (actually any images or artworks) should never be displayed in direct sunlight for prolonged times. Reflected sunlight also contains ultraviolet radiation. Therefore, it is always advisable to display prints under glass. Ordinary glass absorbs about 50% of UV radiation. Use of plexiglass or special UV filters can limit UV radiation by up to 90%.

Humidity

High humidity is another enemy of photos. High relative humidity, especially in combination with high temperature, encourages growth of mold. It also provides the moisture necessary for harmful chemical reactions leading to fading of inks. Ideal relative humidity for photographs is 30 - 50%. Humidity higher than 70% should be avoided.

Temperature

High temperature accelerates deterioration of photographs. The rate of chemical deterioration of most photographic materials and inks is approximately doubled with each 12°C increase in temperature. Ideally, prints should be kept at 20°C (70°F) temperature or below.
Even if temperature or humidity stays within allowed limits, excessive fluctuations are also damaging. These may lead to structural damage within prints, such as cracking of coatings or warping of paper.

Contamination

This refers to various aggressive chemicals present in materials and atmosphere. Non-archival materials may emit gases during natural deterioration process. These gases together with pollutants present in the atmosphere will harm inks causing them to fade and shift color. Although it is difficult to avoid airborne pollutants, especially in the urban areas, exposure of prints to the pollutants can be limited by displaying prints behind glass and storing them in sleeves.

Storage materials

The following materials are considered safe for storing prints:

  • Acid-free papers
  • Polyester (e.g. Mylarr®)
  • Triacetate
  • Polypropylene
  • Poluethilene
  • Tyvek®
  • Contact of prints with the following materials should be avoided:

  • Glassine envelopes
  • Vinyl or other platsic sheets containing PVC
  • Kraft paper envelopes
  • Non-acid-free paper
  • Paper clips
  • Pressure sensitive tape
  • Rubber bands
  • Adhesives in genaral
  • Additional Reading

    There is plenty of information about this subject on the internet. Below is a small selection of useful links:

    Paul Roark's digital BW printing index - excellent source of information about printing black and white photos with dedicated archival inks.
    Wilhelm Imaging Research - widely known and respected authority on archival issues.
    Light Impressions - online suppplier of archival materials.
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