White or green phosphor: the honest answer

It is the second most common question we get, right after whether any of this is legal at all. And it has an answer that the trade rarely states this plainly, because it does not sell particularly well.

The phosphor does not change the performance of the tube.

That is not our opinion. The manufacturer states it directly: between P43, green, and P45, white, there are no performance differences in the laboratory, and the choice remains a question of user preference. In trials with soldiers under green and under white phosphor, no difference in effectiveness was found.

The cleanest evidence comes from data sheet practice itself: the same tube is listed with identical values for signal to noise ratio, resolution and Figure of Merit, and the phosphor sits alongside them as an option. If it were relevant to performance, it would not sit in the same row.

What the phosphor actually is

At the output of the tube sits a phosphor screen. The amplified electrons strike it and produce the visible image. The phosphor is the coating on that screen, and it determines the colour of the image, not its information content.

P43 is gadolinium oxysulfide doped with terbium. It emits at 545 nanometres, in the green, where the human eye is most sensitive. It decays to 10 per cent in roughly 1.5 milliseconds and to 1 per cent in roughly 3 milliseconds, and it has a high luminous efficiency. That is why night vision was green for decades: it was the most efficient solution with the chemistry available at the time.

P45 is the white screen. Its decay behaviour is comparable to that of P43, which in practice means you get no additional smearing on fast head movements.

P22 still turns up occasionally. It is an older green screen family, met mainly around Gen 2 tubes.

What speaks for white, stated honestly

There are real arguments. They are simply not performance arguments.

Fatigue. Over a long night many users find a monochrome white image more comfortable than a monochrome green one. That is subjective, but it is widespread enough to be taken seriously, and it is the main reason white has prevailed.

Edge perception. Some users report reading transitions and contours better in white. We pass that on as field experience, not as a measurement. The manufacturer publishes no robust comparative spectral data, and we are not inventing any here.

Familiarity. Anyone who has never looked through a night vision device usually finds a white image immediately more natural. That is not a technical argument, but if you use the device occasionally rather than professionally, it is the most relevant one.

What speaks for green

That exists too, and it tends to be left out of sales conversations.

Habit. Anyone who has worked with green night vision for years reads a green image faster. That is trained perception and it is real.

Compatibility within a team. If everyone else on the team has green and you are describing to each other what you see, consistency is worth more than preference.

Price. Green is usually cheaper on the market, for reasons of supply, not of quality.

The premium, and how to place it

On the market, white regularly costs a three figure amount more than green.

If the manufacturer says there is no difference in the laboratory, then that premium is a market premium, not a physical one. It arises from demand and availability, not from better measured values.

That is not an accusation against anybody, and it does not mean you should not pay it. Less tired eyes after four hours are a genuine benefit. It only means this: you are paying for comfort, and you should know that when you do. A premium sold to you as an increase in performance is labelled wrongly.

How we handle it

Our devices are built in white, P45. That is the default, because it is what nearly everyone asks for, and because we stand behind the comfort argument.

Green we supply on request. We do not hold it in stock, so it takes longer. If you have a reason for green, habit, team compatibility, or simply because that is what you want, talk to us and we will be honest with you about feasibility and timing.

What we do not do: sell you white as sharper, more sensitive or longer ranged. It is not.

The short version

  • The phosphor does not change SNR, resolution or Figure of Merit.
  • P43 green emits at 545 nm with high luminous efficiency, P45 white has comparable decay behaviour.
  • White is a comfort decision: less fatigue, and for many a more comfortable edge perception.
  • Green is a decision about habit, team or price, and not a bad one.
  • The premium for white is a market premium, not a performance premium.
  • Your eyes make this decision, not a data sheet.

And so the only recommendation we really make here: look through both, in a dark room, one after the other. The difference is visible at once and the preference usually settles within a minute. The showroom in Villmergen is open by appointment.

Questions at any level of detail are welcome. info@dtdsystems.ch, +41 76 225 50 04.

Related

Our standard builds ship in white phosphor, the DTD PVS-14 and the DTD 1431 MkII among them, and green remains available on request. One exception exists as a limited run: the 1431 MkII GP Operators Bundle on green P22 tubes.

Our standard white phosphor builds are here: buy night vision in Switzerland.

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