His case reached the Appeal Court today as his legal team urged three judges to cut his sentence, claiming it was far too harsh.
The trial judge should have taken more account of Bolton's advanced age, fragile health and otherwise good character, it was argued.
Mr Justice Knowles agreed that a 19-year sentence was "an enormous thing for a 78-year-old person in poor health to face".
But the trial judge had this factor well in mind when he sentenced Bolton, he added.
"The fundamental question is whether the overall 19-year sentence for this sustained and grave offending over the course of 20 years was manifestly excessive.
"In our judgment it was not and we would dismiss the appeal," the judge concluded.
Bolton watched the case via live video link from his prison.
The pensioner committed his crimes while a junior housemaster at the now closed boarding school - dubbed the "Jewish Eton" - preying on eight boys aged between 11 and 15.
Victims told how he groomed them by offering comfort to home-sick youngsters, styling himself a "second father".
One boy said he was lured into Bolton's web by the prospect of an unlimited supply of chocolates.
Some of his victims were also forced to "relive their childhood nightmares" when they testified at his trial, the court heard.
