I've noticed a different warm up pattern with different HPS bulbs. Some lamps would go through a color like clear MV, while some don't. All of my HPS lights show this pattern.

• White xenon color at about 30 seconds
• Deep yellow color  at about 1min 30seconds
• Regular HPS color at about 3 min

I also seen (never used) some HPS that have the mercury color between the deep yellow color and the white xenon .

The color patterns during warm up of a HPS lamp, strongly dependent on the age of the lamp and the amount of sodium on it. This may also vary between manufacturers. Several HPS lamps starts orange LPS directly, than just increase in brightness.
New HPS lamps indeed jumps from xenon white color to oragnge LPS and than regular HPS yellow color. But older lamps have the bluish mercury color between the xenon white color and the orange LPS color.
Leaked HPS lamps, starts out xenon white color, then bluish mercury color for several time, then greenish white clear MV color, then pinkish white for both the orange sodium and the mercury color, than a reddish orange color, because the sodium D line in these lamps, that have HG rich plasma, boardens only to the red and the MV radiation contributes to the color.

Some 10-15+ years old HPS lamps actually do wait many minutes in the clear mercury color, before beginning to change to HPS, yet after that are working ok as HPS and not cycling

Most of the HPS lamps I have start out xenon white, then start changing quickly to the LPS yellow colour and continuing to warm up to the golden white final colour, with no mercury radiation noted. Higher wattage lamps tend to stay longer in the xenon white stage.

As lamps age a year or more, some of them show the mercury blue during warmup (which I love) and in some cases never turn yellow, instead kind of a pinkish white before getting to final colour, which by that time is more pinkish/red than when the lamp was new. I assume this is caused by sodium diffusion or leakage out of the arc tube.

I've had a number of lamps never show the mercury blue stage, even when they start cycling. The most unique HPS failure I've ever seen was the streetlight in front of my parents' home. The lamp would start off dim orange, and stay that way for a long time, then flicker for a while, change to LPS yellow and flicker/blink a lot before it finished its warm up and burned normally. It would take longer to warm up every day, until its last day when it took over 5 hours to get out of its dim glow state. Then it went out all together. The ignitor was still fine. The arc tube and outer bulb were  quite blackened, but the arc tube seals hadn't leaked. I never saw any mercury radiation in the discharge, ever in the course of that lamp's 8 years.

I seen GE Lucalox to tend to only show sodium color during the entire process

I also have some generic Chinese lamps ( ) that do that as well.