The altos aren't really dim, but the GE Starcoat SP lamps are brighter. Those non-alto Philips NATURAL LIGHT ~5000K lamps are really dim compared to a cool white plus Alto too. I went over my granparents last night for an early xmas party and didn't need to change any tubes. The newest lamps are from 2012 and are Alto CWP lamps. before that are non-alto 5000K high-CRI lamps (only two of them). before that are daylight altos from 2008. the earliest lamps are the original lamps, which are unbranded (but made my philips) 1996 F34T12/CW/EW Econ-o-watt tubes. there are about 12 of them left, which isn't bad out of 32 lamps.