“When you are a photographer, you work all the time, because your eye is the first camera.”— Patrick Demarchelier
Many times, colored filters are often referred to by their Wratten numbers. The Wratten system was originally developed in 1909 by the English firm of Wratten & Wainwright when they published a bookThe Photography Of Coloured Objects. Established in the 1877, the company primarily made photographic plate and chemicals and in the 1880s and ’90s also produced cameras. In 1912 George Eastman acquired Wratten & Wainwright and the name, for filters anyway, stuck.
One of the most popular camera filters for shooting infrared is the Wratten 89B and it’s one the three filters in my IR kit. The actual filter I use is Cokin’s Infrared 89B filter. Instead of using the filter in a Cokin holder, typically I hold the filter against the lens to avoid daylight coming in from the sides and polluting the IR. You can read about what the other two filters are in my infrared filter kit here.
When shooting infrared with filters, I like using the 89B because it’s the least expensive infrared filter that I’ve found so far, especially in Cokin’s A-series (67 x 71mm) size that works great with most digital SLRs and mirrorless cameras. Purist will recognize that this filter only permits 50% transmission of IR light at 720nm while others, such as B+W’s slightly more expensive ($79.95 in 58mm) filter, passes 90% of IR radiation—its not really light because it’s invisible—from 730-2000nm.
My book, The Complete Guide to Digital Infrared Photography is currently out-of-print but copies are available from Amazon starting at $19.95, as I write this. Creative Digital Monochrome Effects has a chapter on IR photography and is available from Amazon with new copies under $10 and used copies selling for $2.55 (plus shipping) one of the best book deals out their for what is my personal favorite book.