Yes, they can be replaced with wratten filters. I just spoke with tech support for my Tobias TCX and they told me which wratten filters go in it. I have it written down somewhere, but they may not be the same for the Kodak machine. They did tell me that they routinely throw old filters away that never sold because they fade over time, even without use, so if I get my own, I had to be sure they were made recently. They also told me how to calibrate my machine without using their expensive calibration card using the proper ND filter. Fortunately I had the right ND filter to follow the instructions.