Using Taylor CYA Test

[Poconos]

I use a fluorescent desk lamp aimed at a white paper then look thru the tube at the light reflected off the paper. Seems like this gives results close to viewing in outside daylight.
Al

[waterbear]

I have noticed that the test gives a higher reading under indoor incandescent ligh than it does outside in natural sunlight (actually I stand in open shade outdoors when I do the test) My readings outside are 70 ppm but indoors in incandescent light it's more like 90 ppm! I'm sure this has to do with the intensity of the light source. Once again, it's not the actual number that is as important as whether you test the same way each time so you know if your numbers are actually changing or just different because of the lighting.