Why our Papers are Made Without the Use of Optical Brightener Additives (OBA's)

Do you have any really bright white papers?

We manufacture our fine art papers without the use of optical brightener additives (OBA’s). The color you see in our white papers is the natural color of the pulp that was used in the papermaking process. Optical brighteners can be used in paper manufacturing to increase the perceived “whiteness” of the paper. Their use results in a whiter and brighter appearance, which can be desirable for many paper types and techniques.

However, for fine art papers there are advantages to selecting papers that do not contain OBA’s. First, the natural white color, or what is known as “optically dead” papers, will remain consistent under different lighting conditions. In contrast, the color of papers that contain optical brighteners can shift depending on light source. Using “optically dead” papers is especially important for artwork that will be scanned for high quality reproductions. Another advantage is that the color of OBA-free paper will remain more consistent over time. While OBAs enhance the perceived whiteness and brightness of papers, they can break down over time, causing color shifts.

Natural white color of Strathmore's 400 Series Oil Painting Paper

Strathmore papers are considered optically dead as they are manufactured without adding any optical brighteners during the production process. Although no OBAs are added in the papermaking process, trace amounts of optical brighteners can sometimes be present in the pulp used to create the papers.

How can you check if a paper is considered optically dead?
If you hold a sheet of paper under a black light in a dark room, you will be able to tell whether or not it is optically dead. If it contains OBA’s, it will glow bright under the black light.

Below is a comparison of our 400 Series Marker Paper (optically dead) next to copy paper (containing OBA’s) under a black light:


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