Field&Studio has been quiet for a while. I’ve been working on a new method of testing, as well as other research, and now the site is back with a new look, and new, improved and even more rigorous testing methods, in addition to the standard news updates and how-to articles you’ve come to expect. In this brief article, I’ll give you a brief overview of the new testing system.
The New Field&Studio Paper Tests
Most people who know me understand I’m a pretty picky guy; I have a surgeon’s attitude toward understanding anything I do, with the ultimate intent of performing to the best of my ability in those tasks. That disposition left me with some nagging doubts about how accurate my printer and paper investigations were, specifically in the area of Zone X (brightness) and Zone 0 (D-max, or maximum ink density). In short, I was concerned I had no consistent litmus for comparing papers across tests, an issue I struggled to resolve in any strength for some time.
After a lengthy period of deliberation, however, I realized I could use a trusted tool for studio and commercial photographers: an X-Rite Color Checker Classic (see Fig. 1). I’ve gone through many of these over the years, and it struck me that X-Rite provides a definite measurement table for each of the patches, providing me with a consistent baseline for a paper test (see Fig. 2; download the chart from X-Rite here).
To test black and white print quality for papers, I print test images of my Zone-RGB-Lab scale (see Fig. 2). In the case of my trusty Epson Stylus Pro 3880, I print neutral prints for four of the five tone settings in Advanced Black and White mode: Normal, Dark, Darker, and Darkest. On my department’s Canon ImagePROGRAF-1000, there are no such controls, so only a neutral print is made (I’ve suggested to Canon the driver needs to address this issue).
After numerous requests for input on ICC profile accuracy and comparisons, I have also now incorporated a new color testing scale, developed by combining my own Zone scale with OCP’s excellent color testing materials (see Fig. 3; download the charts from OCP here). I’ll explain the process with this chart in a later post, because, well…it’s complicated stuff.
I produce the test shots using a Beseler CS-21 copy stand outfitted with 5500° Kelvin CFL photo bulbs at 45° to the subject paper, which is consistent with what I have done in previous tests. Shots are made with a Sony A7R body and a Canon 100mm macro lens. I first make an image of the Color Checker at ISO 400, f/11 and 1/30 second exposure, and then shoot sequential images of each test print.
The challenge, however, was to calibrate the prints against the Color Checker. I solved this problem by using the known LAB values of the gray-value Color Checker patches to color-correct the initial raw image to the appropriate values (see Fig. 4). While there were inevitable slight variations in the final middle-range values (+/- ~ 2 luminance points in several cases), the system is as close to fully controlled as possible without the use of a neutral color viewing station (which I don’t own).
I then add the calibrated image in the images of the test prints (see Fig. 5). Thus, I now have 6 known values that are independent of individual paper contamination, providing me with reference luminance values. I can then compare these values’ accuracy in the new file, and then have reasonable confidence any other Lab values I measure are accurate as well.
Translation: Now, both brightness and D-max are more reliable in my tests. What that means for you is that you can see and read how which papers will work best for your needs.
And so that’s the new Field&Studio process. The downside is that it will invalidate all my previous test results, but after all, that’s the process of investigation and progress. And as always, I hope this blog helps you discover your next print is your best print.