Printing Tagged Objects
In addition to the information in this topic, review the specifications for each tag type in the Byte Tags and Identity Tags topics. If you are printing identity tags, you should also use the identity tag printing tool.
Make sure that printed tags meet the following requirements:
The white dots must reflect at least 73% of 850 nanometer (nm) infrared light but not more than 86%. Ultra high reflectivity whites can cause "bloom," which impairs the vision system's ability to recognize the tag.
The dark region must not reflect any more than 7% of 850 nm infrared light (93% or more should be absorbed).
Note Limited tests show that a non-IR reflective or black background that is at least 1 inch larger than the tag itself can improve how tags are recognized, even if they are on a background with reflectance higher than 83%.
A single tag on a physical object with a black or non-IR reflective background provides the best tag recognition performance.
You can measure reflectance for surfaces with diffuse reflectance by using a reflectometer that has response in the near IR wavelength range (for example, the InspectIR-Vis instrument from Surface Optics Corp).
Materials and Placement
Whenever possible, place tags on infrared-absorbent objects. A tag on an object that is infrared-absorbent typically performs better than a tag on a highly infrared-reflective item. If you place a tag on a highly infrared-reflective surface, the Microsoft Surface Vision System might have trouble recognizing the tag.
|The infrared reflectivity of an object is not necessarily the same as its brightness to the naked eye. For example, some materials that appear dark to the eye can actually be reflective to infrared light.|
You must place tags on a solid, consistent background (for example, with no patterns or stripes). Use a dark-colored or non-IR reflective background instead of a light background.
Place tags on flat surfaces that help the tag maintain flush contact with the tabletop. Also, tags work better on physical objects that do not easily tip over while they move.
The following materials and processes have been validated and shown to produce tags that function correctly with Microsoft Surface. If you use these materials, your tags should work properly. However, always test new tag types in their final format before you distribute them.
White office paper
White print labels (for example, Brother TZ-261)
IR-reflective dielectric coating on PET film
In general, most white paper works well. However, some are too bright and can cause a blur in the Microsoft Surface Vision System.
Laser printer black ink
Pantone Black C
Epolight 8771 IR absorbing ink
Top coats and protective layers
In practice, top coats such as UV print varnish and laminates can successfully improve a tag's durability and minimally affect the optical properties of the tag. However, many types of protective layers can significantly affect optical performance. You should test any protective layer that you add to a tag to make sure it performs correctly.
Ink jet printers that use a mix of cyan, yellow, and magenta to create black generally do not work. The three-color combination is typically invisible in the infrared spectrum. You should test all printing methods for their appearance in the infrared 850 nm wavelength.
Be careful that the tags cannot be rubbed off. Tags that are printed by using ink jet or laser printers wear off rapidly when they are used. If the tag printing wears off, you cannot use the tag anymore and the tag will smudge the Microsoft Surface screen. The tags that are included with the unit are printed on self-adhesive vinyl to protect them from wearing off.
|Do not use the Microsoft XPS Document Writer to create an .xps file for later printing of the identity tag. The XPS Document Writer introduces light gray lines that outline the small hexagonal areas of the tag. These lines can prevent the Vision System from detecting the tag.|