Hi all, one of my local grocery stores is getting a renovation. The drop ceiling is gutted and all that’s left are the lines of GE Starcoat fluorescents and the air ducts. Their light is quite nice and I was wondering how Starcoat is different from Reveal fluorescent.

As far as I know Starcoat and Reveal are two completely different types of phosphor coatings.
I believe Starcoat first appeared during the early 90s and was intended for GEs new line of T8 tubes.
The coating was better than the traditional colors like cool and warm white and still even better than the deluxe versions of these colors.
All Starcoat tubes had a very high CRI rating.
Starcoat had no lumen loss, actually the tubes were even brighter another benefit to this type of coating.
I remember that T8s with Starcoat in 3500K were extremely popular in all types of commercial buildings.

Reveal fluorescents have a completely different coating and I believe the concept behind them was to give off a color of light similar to the Reveal incandescents.

That's interesting what you said about the grocery store remodel.
That there are still rows of Starcoat fluorescents.
I always thought they were good quality tubes and wouldn't mind adding some of those older Starcoats to my collection, sure brings back some memories.

That's interesting, in Europe we also had the Starcoat brand on regular CRI tubes (Ra80+ Triphopsosphor). 

This brand was introduced at the same time that GE pioneered the so-called "Water on Water" process in the lamp manufacturing.  The tubes were first given a thin pre-coating of aluminium oxide nanoparticles, and then a second coating of the triphosphor.  Both were uniquely water-based suspensions rather than the earlier butyl acetate solvents, which were far better for the environment.  And stopped the employees getting high on the fumes that used to intoxicate all fluorescent factories with the characteristic smell of pear drops!

But the most important feature was the pre-coat of Alon powder (GE was not first with that, I suspect it may have been an Osram or Philips invention).  In all fluorescent lamps, one of the major mechanisms of lumen depreciation over time is an effect in which the ionised gases in the tube draw sodium ions out of the glass wall to the surface.  The sodium then reacts with the mercury dose in the lamp to form sodium amalgam, which forms a greyish coating that progressively absorbs the light output as well as the mercury.  Since the Starcoat lamps significantly reduced the rate of that process, they delivered greatly improved lumen maintenance, useful lifetime, and could also be manufactured with a greatly reduced mercury weight.  As far as I know this same approach was also used for the Reveal tubes.  Most to the top quality tubes from the main manufacturers use this technique since the 1990s.

If you look at any modern Germicidal tube from a reputable manufacturer who uses the same technology, you can see the Alon-C coating.  It is only a few nanometres thick and as such creates an optical interference effect, which gives a kind of feint rainbow effect to surface reflections in the glass.