Phooey to 68 F!

That's a historic relic derived from European tap water temperature being the basis for processing photographic materials. Here in Australia my tap water rarely runs that low and I reckon it doesn't matter. The important thing is that all processing solutions including the tap-water wash be the SAME temperature to avoid thermal shock to the wet emulsion.

My approach is to develop at tap water temperature and adjust the developing time. For (replenished) Xtol my time/temperature experiments indicate for Tmax 100 at 55 Farenheit 23 minutes is right while at 95 Farenheit 2 minutes 40 seconds does the same thing. For temperatures in between my time adjustments fall in an orderly way. Other films behave in a parallel manner and a few initial trials tell you what you need to know.

The anxiety about too short developing times leading to uneven results is overstated. With a properly pre-wet film in a Paterson (or similar) developing tank and a ready-to-hand jug of developer and the willingness to pour and agitate quickly a 3 minute developing time is no problem at all.

There are supposed to be "soft emulsion" films out there but I've never had Efke, Adox, Foma, Ilford, Fuji, or Kodak misbehave at any temperture. I figure if the only things touching the emulsion are air plus liquid for a short time what's going to wreak damage. It's worth remembering that film washes quicker when it is hot. A 4 minute flowing wash at 90 F is as good as a 10 minute flowing wash at 68 F.

For the record my hottest development was in the Australian outback using artesian bore water that came out of the ground at 113 F. The Tmax 100 negatives were fine with a hint of sepia from the sulphur that was in the water too. If you work quickly and carefully film can be processed safely at surprisingly elevated temperatures.