I suspect this "old" GTI lamp was manufactured a long time ago. https://1drv.ms/u/s!AkD78CVR1NBqkLRy3q1Y_l3gK8VkWg I gather there is a code that identifies lamps that meet the new specification. Does anyone know what code I should be looking for? One thing, though. I found this lamp installed in an old GretagMacbeth overhead luminaires, at a client, yesterday. See the data here, in Excel (measured with Minolta FD-7) : https://1drv.ms/x/s!AkD78CVR1NBqkLRz_XP0GZyvIEZh7w The thing is, according to ISO-3664:2009, the light produced by these lamps "shall" (or "should") have energy in the UV part of the spectrum. I'm not sure they specify down to 360nm but that's typically where the optical brighteners components in the paper are excited from, according to my humble information. If the lamp does not produce any energy in that part of the spectrum, hence, the appearance of the proof "will be compromised". (I hope TC130 is starting to work on the new type of LED illumination which will gradually replace Mercury-based fluorescent tubes, because it's going to happen sooner than later.). Just curious, for those who have long measured the "new" 2009 lamps, would you have some kind of data to share? So that I can compare? GTI lights, preferably. Thank you / Roger Breton www.graxx.