In our first post in the series, we talked about ways to protect your photographic prints from the effects of environmental factors like UV light, temperature, humidity, and ozone gasses. In this blog post, we will go back to the beginning and talk about paper composition. Your choice of paper will be one of the most important decisions you make when printing your work, as paper surface influences the look of the image. Make sure the paper is high quality and archival, and you will ensure the prints last for a long time.
What are the important considerations when choosing a paper?
First, select a paper that is light-fast and resistant to disintegration or yellowing. To reduce disintegration and yellowing over time, look for papers that are acid-free and chlorine-free. Lignin-free papers with fewer optical brighteners (OBA) will allow you to predict the yellowing of the paper over time. Second, be sure that the paper is suitable for the inks with which you are printing. We will discuss inks in the final blog post in this series.
Wait, what is lignin?
Some important terms:
Lignin: a chemical substance found in wood that bonds (glues) cellulose, making wood stronger; paper without lignin is not as strong. However, lignin breaks down over time, turning the paper brown and releasing acids.
Acid: Acids can actually make paper better for writing or printing, but will gradually cause deterioration or disintegration. Acidic paper will also become brittle over time.
Buffering: This refers to the addition of alkaline materials into the papermaking process, offsetting or cancelling out the effects of acids. May also damage paper over time.
Primary characteristics of paper
The raw materials, from which paper is made, are your first consideration. Many fine art printers rely on 100% cotton paper, Kozo, bamboo, or baryta. These are the gold standard; a more expensive choice you might want to save for the final print. Another paper type is made out of wood cellulose, often referred to as “alpha cellulose” or “sulfite.” Sometimes, papers are a combination of cotton rag and alpha cellulose. The most important thing to look for is proof that it’s acid-free, meaning, it has a pH value greater than 7.0. The truth is, most good fine art papers meet these specifications. Freestyle Photo has an awesome comparison chart of different papers and their characteristics.
How white your paper appears is another creative choice with long-term implications. Very white papers have high contrast and color, along with a wider color gamut. Depending on your imagery, it can be a creative eye-popping option. Unfortunately, paper is not naturally white, so there are changes made by the manufacturers influencing how we see the paper color.
The methods used to make your paper appear whiter are bleaching, white colorants added to the paper base – or more commonly – the addition of OBA, or optical brighteners. Optical brighteners tend towards blue and usually work with a fluorescent additive that absorbs UV light and re-emits or reflects white light back to your eye. If you look at these papers in the dark, with a black light, you can see the papers that fluoresce are the ones containing various amounts of OBA. The ones that do not fluoresce, contain no OBA. Optical brighteners are not just for inkjet papers. There are other times in your life when you encounter OBA, like every time you use laundry detergent.
How is print permanence measured?
In the world of fine art photography and printing, Wilhelm Imaging Research is the accepted standard for rating and testing print permanence and light-fastness. They are well-regarded in the community because they are independent and, therefore, considered unbiased. Think of them as the Consumer Reports of Fine Art papers. Be aware though, display permanence ratings are just predictions based on accelerated testing. You can read more about their process here.
Some basic paper handling tips:
- Before Printing
- Keep the paper in the manufacturer’s box
- Store in a dry, cool, and dark location
- Wear cotton gloves when handling (avoiding oils and perspiration)
- Dry brush the surface before printing. This is especially important for removing stray cotton particles from the surface of matte papers. Ink will stick to the cotton particles, then flake off leaving a blank spot in your image.
- After printing
- Don’t contact the print surface while it dries
- Dry on a clean, flat surface
- Allow a minimum 1-hour dry time before handling
- Do not frame your print for a minimum of 24-48 hours, a week is best. This will prevent off-gassing and fogging the inside of the glass as the print dries.