For those of you intending to build one of the CEPs...There are a couple of important things I learned when building the sensor that you might find helpful.
I had done what I thought was a really nice job of encapsulating the entire bottom part of the photo diode, from the side rim of the photo diode, all the way down to where the cable begins, making absolutely certain not to get any caulk on the face of the photo diode, so as to not obscure in any way the area where the light is collected through the photo diode surface.
I thought this would seal everything up really well, but the caulk must have acted as a conductor, causing the leads to short, and readings to be way off on the meter. So, I pulled the caulk loose, and cleaned everything up (once the caulk was dry). Readings came back to normal, and the meter starting working perfectly again. Maybe it's the brand of caulk I used...who knows? I used a caulk made by Locktite that comes out white and dries clear. Perhaps another brand, such as GE Silicone, would not have caused this problem...not sure. If you do caulk the leads, make sure you allow several days for it to dry. Perhaps that would have avoided the issue of the leads shorting. But, after waiting at least two days for the caulk to dry, I still experienced the issue with the short, and the meter returning bogus readings. I also tried caulking where the jar lid meets the jar, on the inside. But, drying time was so lengthy, that I abandoned that idea, and cleaned all the caulk up that was on the inside rim of the jar rim and lid.
I finally decided just to caulk the outside surfaces of the jar rim where it meets the lid, also caulking around where the cable meets the cable connector. I also completely caulked the cable connector where it meets the outside top portion of the jar lid where the cable enters the jar. Actually, I made two applications of caulk, allowing the first application to completely dry before moving on to the second application. It seems to have sealed very well.
So, caulking the leads of the photo diode doesn't really seem to be necessary. But, if you do it, I would recommend caulking each lead separately, and trying not to get any between the leads, allowing it to dry a long time, thereby avoiding potential for a short between the two leads of the photo diode, assuming mine wasn't sufficiently dry after two days. When I soldered the leads, I also used heat shrink on each lead, which I thought would sufficiently insulate the leads from a short by the caulk. But, I suppose that enough caulk migrated from one pin entry point into the diode to the other pin entry point, and created a short.
Also, if you want to layer the Rosco Filters the full diameter of the acrylic diffuser, like I did, this may be of interest. I requested some sample sheets from Rosco Filter Company, requesting a sample of each of the specific types that are outlined earlier in the thread. I requested them in the size 6" x 10", so I would have plenty to work with, since I have several PCBs, and figured I might want to build more at a later date. I never received an answer from them after making my request with their customer service department via email. But, low and behold, a sample of each showed up in the mail today, in the size I requested, 6" x 10", and free of charge.
Also, just so you are aware, the face of the photo diode is pushed all the way flush with the Acrylic Diffuser/Rosco Filter Sandwich on the inside of the jar. I then painted the jar because I figured that mine looked better that way, and I figured it would also limit light entering the jar from the sides/lid of the jar, thereby directing light only through the surface of the diffuser. I doubt that it's functionally necessary to paint the side walls/outside lid of the jar, but it can't hurt.