The judging of lamp brightness by its glare is not result of damage, but simply of the appearance of high glare LED light sources, everywhere where the previous sources were not as glaring :

 - Flat panels with flat light distribution replacing highly directional reflector modular luminaires (4x18W)

 - Floodlights lacking any optics whatsoever replacing way bigger in size HID floodlights which did have optics

This had been going on, and actively abused for sales and promotion, since the earliest days of high power LED lighting, so way before anyone had the time to get vision damage

With additional vision damage the demand for bright light (which tends to correlate with being 6500K, probably to compensate for the degraded S cone cells) will remain the same or increase

Your mom is on one end of the scale, where for many it is the opposite effect. Of those who want bright light like your mom, i wonder how much of it is attributed to actual vision damage (whether from LEDs or just from age and other health factors), vs. how much when actually seeing the same "picture" as me (for example) but claiming that it is not bright enough, in the same cases where i would consider the light level adequate

The fact that lots of people judging the intensity of LED lamps by the glare of it, proves my thoughts about degenerate of the vision of people.
Also: My brother and my father and my mother all preferring >6000K, because they saying it is brighter than 2700K, and my mother because she don't see well with <4000K light.

Color temperature is very strongly correlated to cultural background here. In row homes where families are mostly from western european descent, 2700k.
In apartment blocks, where many of the turkush, morroccan and middle eastern people live, you'll find 4000 and 6500 more often because of the apparent correlation between living near the equator/in a very warm country, and wanting a cooler shade of light.

Always been like that only in the pre-led days, their only choice was 4000k circular (kinda rare) or linear fluorescents in the living room. CFLs we didn't have in 4000k, unless you went for PL but at hardware stores all PL fixtures were meant for outside use. So only the die-hard fans of cold white light would have a brightly shining fluorescent right in their living room.

The length of arc in air which this PZT ignitor can produce can give you an estimate of the order of magnitude of its output voltage

In uniform field, air requires 3kV/mm to break down with high probability, with some behavior properties :

 - ionization is always a statistical phenomena, dependent also on factors like photoelectric effect and radiation

 - The presence of a nearby surface of a different material, even if it is in itself dielectric, may sometimes facilitate the arc striking in a path from one electrode towards the surface, in a straight line on the surface layer, and to the other electrode

 - Some surfaces of solid materials may have additional insulation breakdown mechanisms such as tracking, which will happen at way lower field strengths. However, the initial starting of tracking is a relatively slow phenomena and unlikely to happen with the fast pulse of a PZT. Air by itself does not have such mechanisms, only the basic breakdown as result of applied field

 - If you are looking instead for a distance which is safe to NOT break down, that would be no more than few 100's V/mm, and that's without any surface related mechanisms. The AC voltage ratings vs. contact opening distance of small low current relays may give you an estimate here

In non uniform field, the electric field will be concentrated near sharp edges. This means that even if your real voltage and distance between electrodes would calculate as lower field strength, there still will be a region of field way above the 3kV/mm. Once a small region is ionized, it is easy for the arc to spread from there to anywhere else as needed to complete the circuit, even where initially the field is weak

The lamp glass wall have up to 10x the permittivity of air, alumina (HPS arctubes) also 10x, and quartz 4x. (abridged explanation : imagine the 1mm glass wall behaving as a 10mm air gap etc)

The atmosphere in the lamp outer is generally vacuum or nitrogen, which have permittivity same as air

With this said, try to imagine if the arc would reach the lamp electrodes if you would zap it as you do, from the same position, if there would be no lamp or arctube or outer envelope there, but just the PZT and bare lamp electrodes at the respective distances (with the extra air distances that represent the arctube and lamp walls)

If it does, odds are it can strike the arc. If it does not, it may still strike it, because there may be additional conditions which reduce the extra "push" the lamp needs in the 1st place

I have a Universal USB-1024-14 sign ballast and I was wondering if it can run 4 F24T12/HO lamps, originally I was planning on buying my F36T12/HO lamps from Granger because they were on clearance and I thought that they had 21 cases of 24 for $1.27 per lamp, but I found out they have 21 lamps for $1.27 per lamp,and its pickup only too. Anyhow, I can't find any F36T12/HO lamps at a comparable price. So I was wondering if my Universal USB-1024-14 ballast could run 4 F24T12/HO lamps despite needing atleast 10 feet of tubing according to the datasheet. If it can't, do any of you know where I can find cheap. F36T12/HO lamps at, preferably for less than $3.40 per lamp?

At one point I wired up a HPS ballast with a dead ignitor to a piezo ignitor used for BBQs and the HV pulse from it was enough to start the lamp.

It depends. Piezo generator from a lighter certainly generates a few kilovolts, so if you run wires from it to lamp electrodes, likely the burner will strike momentarily. Just clinking the intact lighter nearby the lamp will be helpless, not enough field strength I guess...

Laurens :
The culture here is different. It is very diverse, some people have preferences similar to what you describe, some entirely opposite

I can confirm that there are more people here who will call anything other than 1000 lux 6500K in their living room "bad lighting"

Those existed as far back as i can recall since young age. In the 90's that would be 160W MBFT's in a nice 5 arm chandelier (that one was in a big room of an old house), in the inbetween years that would be with grow-light size CFLs still in the same chandelier, and nowadays it is equivalent light levels with awful flat LED panels



LAB27 :
There are people with 6500K setups, both those who are excessively bright (what we have been discussing here), and who are dim to normal. The latter ones became clearly visible with the CFL boom in the early 00s and now LEDs, but they always were out there, even in the old days with plain 1x20 Fluorescents

Many people, especially in the "i want very bright light" camp, judge the quantity of light by the visible glare from the luminaire and not by the actual light levels resulting in the area. LED luminaires are at the absolute top by glare, so they always appear "good"

In road lighting there is an additional factor : LED luminaires are very highly optimized to make uniform light levels (low Delta) along a theoretical road with perfect luminaire positions

First, "lens panel" optics emit legendary amounts of glare while directing the light to achieve this uniformity (which isn't even required to see well under the light). See reaction to glare above

Second, when the terrain is not an ideal straight road and luminaire positioning is a bit ad-hoc (as it is in virtually all of Hadar for example), the pattern put out by those LEDs will cause over illuminated spots to really stand out, something which is not so obvious with HPS

@dor123 No, that's not true.
What I think is happening is that compared to previous decades, 6500k lighting has become more common indoors and in streetlights. Before it would by 2700k - 4000k indoors, and orange HPS outdoors.
The color 6500k looks brighter than other color temperatures even with same lumen rating. So even if the new LED replacements are equally as bright as incandescents, fluorescents and HPS Lamps, the color temperature makes it seem brighter.

Also: Most LED streetlights at Kiryat Ata, are brighter than the former HPS streetlights.

The HPS-LED change is also because of color. One example is a 250w HPS streetlight being replaced by a 200w 6500k LED streetlight. Even though the HPS with ~27000lm is "brighter" than the LED with ~22000lm, the color of the 6500k LED makes it seem brighter than the HPS.

what about the piezoelectric spark form a lighter? Is that strong enough?