Print permanence

Key takeaways

Print permanence belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Print permanence to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Print permanence from memory before moving on to harder problems.

Reference excerpt

Print permanence refers to the longevity of printed material, especially photographs, and preservation issues. Over time, the optical density, color balance, lustre, and other qualities of a print will degrade. The rate at which deterioration occurs depends primarily on two main factors: the print itself, that is, the colorants used to form the image and the medium on which image resides, and the type of environment the print is exposed to.

Inkjet prints For inkjet prints, pigment-based inks last generally longest when used with specific paper types, whereas dye-based inks can be optimal on more types of paper. Ink-jet paper types include swellable paper, porous paper, and cotton rag paper.

Chromogenic color prints (silver halide prints) The longevity of images on chromogenic color photographic papers depends on the temperature and relative humidity of the storage environment, and on the total light exposure they receive. Older chromogenic papers undergo more rapid fading compared to modern materials. For example, Fujifilm's Crystal Archive papers have a quoted longevity of sixty years dark storage. The stability of coupler-incorporated chromogenic prints has steadily increased since their introduction by Kodak in 1942. Very significant advances in stability were made in case of Kodak prints in 1954, 1958, and in the early 1980s. These changes can often be used for the dating of color prints, and can be correlated with manufacturing changes documented in the technical literature.

Monochrome prints In general, black-and-white prints using either silver or carbon-based media may last longer than some colour prints. Some black-and-white prints are produced using ink-jet printers, or colour photographic paper using the RA 4 process.

Gelatin silver prints To achieve a long lifespan, gelatin silver prints must be thoroughly fixed and washed. Besides rendering the image insensitive to further light exposure, fixer converts undeveloped silver salts in the emulsion into products that can easily be washed away. Effective fixing and washing removes all unexposed silver salts and leaves only a small amount of residual fixer. Any significant quantity of fixer (thiosulphate) left in the print after washing will cause the image to deteriorate over time. Many other factors play a critical role in the long-term stability of gelatin silver prints. The temperature and relative humidity of the storage environment, and the air pollutants to which a silver image is exposed are three of the most important factors. Toning can increase the longevity of silver-based prints by replacing or coating the metallic silver with more inert metals such as gold, silver sulphide or selenium.

Platinum, palladium and other inert metals Images composed of more inert metals, like platinum, palladium and gold are less prone to decay than those in silver. Amateur Photographer's Dictionary of Photography said "Owing to the chemically inert nature of platinum, a print so made is far more permanent than any print having a silver image can be". Indeed, the Victoria and Albert Museum's Conservation Journal states that "...the majority of the deterioration seen in such prints is usually associated with the supports, which are often yellowed and brittle, rather than the actual image."

Environmental factors Environmental factors that hasten the deterioration of a print include exposure to heat, ozone and other pollutants, water or humidity, and high levels of light. Though light-induced fade often gets the most publicity, greater than 90 per cent of consumer prints are stored in the dark where the effects of heat, humidity, and/or pollutants can dominate.

Research and standards Much research into image permanence has been carried out by Wilhelm Imaging Research, Inc. Some film companies and printer manufacturers are researching ways to increase the lifetime of their prints. The International Organization for Standardization has developed standards for keeping photographs, defined in ISO 18920. Those standards have yet to be extended to digital print output, though the organization has signaled its intent to provide such standards.

See also Preservation (library and archival science) Digital permanence

References

External links Arthur H. Bleich (2004)."Going, going, gone! How to Create Prints that Last". Digital Camera. Bugner, Douglas; LaBarca, Joseph; Kopperl, David; Phillips, Jonathan; Skye, David; Baker, Irene; Cunningham, Caryn; Miller, Paige; and Kaltenbach, Thomas (February 2004). "HomeEnvironmentSurvey_en.pdf Survey of Environmental Conditions Relative to Display of Photographs in Consumer Home". IS&T's Thirteenth International Symposium on Photofinishing Technologies. 13, 31-36. ISBN 0-89208-249-6. In-depth white paper (Epson) White paper on image permanence issues (Kodak) International photo industry website on image preservation International Organization for Standardization (ISO)Technical Committee 42, Photographic Standards Published and Under Development

Worked examples

Example 1 — a first encounter with Print permanence

Start with the simplest possible case. Write down what Print permanence claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Print permanence before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Print permanence ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Print permanence

In research: Print permanence appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Print permanence in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Print permanence is common in secondary-school and first-year university syllabi. It links to neighbouring topics Science of photography, so understanding it makes those chapters shorter.
In everyday life: Look for Print permanence outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Print permanence in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Print permanence means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Print permanence out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Print permanence in simple terms?

Print permanence refers to the longevity of printed material, especially photographs, and preservation issues. Over time, the optical density, color balance, lustre, and other qualities of a print will degrade.

Why does Print permanence matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Print permanence?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Print permanence.