Hi, Erik; you absolutely need to use some kind of calibration; here's something you can do. You WILL need to know actual density values of a test target; the easiest way is to have someone with a known calibrated machine to read it for you. It won't be as good as a first generation test plaque, but ought to be adequate for what you're intending.(posted 8279 days ago)For transmission, develop a piece of B&W film to a density of about 3.0 (this is really dark and typical of an X-rite calibration patch). Maybe collect some old pieces of film leader (that was fully developed). There is a good likelihood that some will be close to this density. Ask a pro lab, etc, to read a few test strips for you. You will want these to be using the "visual" response. If you want to also calibrate the RGB channels, you could ask them to also read these; they ought to be pretty close to the visual number.
Once you have a piece of film close to 3.0 density, get your machine in 'T' (transmission) mode by pressing the "T/R" button. Then press "CAL". When it says "calibrate NO YES", press the button below "YES" (it's the "CAL" button). It will then display "T V:Hi = " something. Use the buttons under the up/down arrows until it reads the same as the "visual" density of your calibration strip. Then press the button under "V:Hi" (it's "COLOR") to cycle progressively through R, G and B. Put in the appropriate numbers; if you don't have color numbers, use the same visual density number. Finally, it will ask you to read "…NO FILM" followed by reading "…STD:HI", which is your calibration strip.
Your transmission mode should now be calibrated. To double check, with no film it should read 0.00 +/= 0.01 or so. The film patch should now read whatever value you entered in as the value. PS: I checked the settable limits of one particular machine; it could be set anywhere from 1.50 to 3.50; however, as I said before, X-Rite seems to generally use about 3.0.
The reflection mode works in a similar manner, except that you will need a "white" patch. I would personally use a piece of glossy photo paper; both a bare white and a "nearly black" patch. The typical X-Rite check plaque had a "black" patch density of about 1.80.
Have fun with your new machine. If any further questions, feel free to email!