Color Can Be Tricky

Part II: Optical brightening agents and base tone

Think of papers with optical brighteners as a base tone.

Way back in the last installment of Color Can Be Tricky, I discussed considerations when taking pictures. Specifically blown color channels, white balance, and its role in assessing images in the field. The image at the top is an example of the effect optical brightening agents (OBAs) have when making a picture of a print. I struggle with this all the time when making images of prints in the context of an environment or with other prints on differing papers.

I know that making pictures of prints is not a high priority for many printmakers. It can be when marketing prints for sale and related peripheral activities. I’ll address that some other time if anyone is interested. The reason I brought optical brightening agents up today is that it’s related to the broader topic of considering base tone when selecting a paper.

Let’s start with what OBAs do. Papers treated with OBAs absorb light in the ultraviolet spectrum and reemit them as blue light. The image at the top exaggerates this due to many factors. Those factors aren’t important for the discussion. What is important is that they will look blue rather than neutral. How blue papers appear will depend on the light they are shown in. Most viewers won’t notice it that much, they’re used to ”white” things looking bright blue. If a print with OBAs is displayed next to other prints without them it becomes quite obvious even in light with very little UV or blue spectrum as some OBA treatments are very strong. Mixed display of prints with and without OBA’s looks off. I’d recommend avoiding that when at all possible (take note exhibitors, curators, and organizers of group exhibitions — please).

In many of the print workshops I take part in the subject of pairing the “right” paper to an image comes up. Matt vs. Semigloss vs. glossy is the usual discussion. It gets much deeper than that with specific surface textures, whether the print will be behind glass, what kind of glass, and other mounting considerations. I’d propose that base tone is just as important and possibly more depending on the strength of the base tone.

Think Aesthetically

Now that I’ve satisfied the obligatory technical things I recommend when considering paper base tone you let go of all things technical and approach it purely from an aesthetic point of view. Paper selection and image pairing are an art. Fine art inkjet papers are expensive, treat selection as carefully as you do all the other factors that go into making your photograph.

Here are a few guidelines to consider:

• When in doubt go with neutral, no OBAs. Eventually, you’ll thank me if you are addicted to bright paper.

• Consider papers with OBAs as varying degrees of a cool base tone. Does the image benefit from some degree of a cooler rendition? What about the rest of the images that it will be displayed with?

• Tread carefully choosing papers with a very obvious base color, usually very warm yellows, and browns. These take experimentation and experience but err on the side of less base tone. Does your image call out for a very warm feel? Before even making a proof print do yourself a favor and simulate the base color in Lightroom, Photoshop, or whatever software you use. It’s not hard to do. Even then err on the conservative side. There are certain images that scream for some of those gorgeous Hahnemühle, Awagami, and other brands' papers that are very definitely colored, let the image guide your decision rather than the paper.

• Black and white images that have been “toned” digitally require special attention. Printing those on paper with an obvious base tone is probably a terrible idea. Printing them on a neutral or bright paper usually looks bad or best case “off” if any of the paper base shows. We’ve had to do that but printed the highlight color right on the base of the paper outside the image to simulate a paper with a warm base tone. The best case may be to get rid of the toning and use a paper that has a similar base color.

Keep these thoughts in mind as we’ve planned quite a few paper-paring essays in the queue. We also hope to have a guest offer his thoughts on OBA’s from a different perspective other than base tone so stay tuned.