In short: The colour of a night vision image comes from the phosphor on the tube’s output screen: P43 glows green, P45 glows white (shades of grey). According to Photonis there are no “lab” performance differences between them, and the choice is down to user preference. Tube performance is set by other specs (FOM, SNR, resolution, halo) – check those on the datasheet. If you can, look through both versions before you decide.
Where the image colour comes from
An image intensifier tube works in three stages: the photocathode turns incoming light into electrons, the microchannel plate (MCP) multiplies them, and the phosphor screen at the end turns them back into visible light. The chemistry of the phosphor on that screen decides what colour the image in your eyepiece has.
Phosphors are identified by standard codes starting with P. In night vision you will mostly meet two: P43 (green) and P45 (white). So “white phosphor” or “WP” in a device name means a tube with a P45 screen – not a different generation or a different tube grade.
P43 vs. P45 at a glance
| P43 – green phosphor | P45 – white phosphor | |
|---|---|---|
| Image colour | green, the “classic” night vision look | white to grey, similar to a black-and-white photo |
| Composition (standard phosphor table) | Gd₂O₂S:Tb | Y₂O₂S:Tb |
| Lab performance according to Photonis | no difference vs. P45 | no difference vs. P43 |
| Decay according to Photonis | similar to P45 | similar to P43 |
| Background | the long-standing standard look of night vision | according to Photonis, comes from aviation and special operations |
| What it affects | colour and how the image feels to you | colour and how the image feels to you |
| What it does not affect | FOM, SNR, resolution, halo – set by the tube | FOM, SNR, resolution, halo – set by the tube |
What the tube manufacturer says
Photonis (now part of the Exosens brand), which according to its own materials was the first manufacturer in the world to develop and sell white phosphor tubes, puts it this way: there are no “lab” performance differences between P43 and P45, and P45 has decay properties similar to P43. In trials of soldiers’ performance with green and white phosphor night vision, the manufacturer says no difference in combat effectiveness was found.
The manufacturer therefore describes phosphor colour as a matter of personal preference, with the most important criterion being that the user has as little eye fatigue as possible. It gives no figures for eye fatigue or contrast – so we don’t either.
How it feels: contrast and comfort
There may be no difference in the lab, but many users notice one in the field. These are subjective impressions, not measurements:
- White phosphor is described by some users as more natural – the greyscale image resembles a black-and-white photo, and shadows and shapes seem easier to read. Photonis states that P45 provides excellent recognition.
- Green phosphor feels more comfortable to others during long viewing, and it is the “typical” night vision image many people are used to.
- Perception varies from person to person. Two people can look through the same device and reach opposite conclusions.
So there is no universal “winner”. If you get the chance, compare both under similar conditions – ideally outdoors in the dark, not in a lit shop.
Choosing by use case
Phosphor colour is the second decision. The first is tube quality. Once you know which tube grade you want, these questions can help with colour:
- How long will you be looking? For long sessions (waiting in a high seat, an all-night event), what matters most is which colour is easier on your eyes. The manufacturer stresses this too.
- Are you pairing it with another device? If you already own a green device and are buying a second one, consider the same colour – different colours in the left and right eye can be uncomfortable. In a binocular, both tubes should have the same phosphor.
- Hunting, clip-ons, thermal? Colour doesn’t change performance here; it comes down to what you’re used to.
- No way to compare? Decide based on which looks more readable to you in sample photos and through-the-eyepiece videos – bearing in mind that cameras distort colour and contrast.
What phosphor colour won’t change
Colour is the first thing you notice, which makes it easy to overrate. What you actually see at night depends on the tube’s specs:
- FOM (Figure of Merit) – according to Photonis, FOM = resolution × SNR.
- SNR (signal-to-noise ratio) – how “clean” the image is in very low light.
- Resolution – how much detail the tube can resolve (in lp/mm).
- Halo – the ring of light around a point light source.
- Autogating – how quickly the tube reacts to sudden light.
You’ll find these on the datasheet of the specific tube. We explain how to read one in How to read a tube datasheet. A white tube with a low FOM won’t show you more than a green tube with a higher FOM – and vice versa.
Availability
European manufacturer Exosens (Photonis) offers its civilian ECHO tubes with green P43 phosphor as standard, and they are also available with white P45. The price of a particular tube depends on its specs and the seller, not just its colour – so always compare devices by their datasheets, not by the colour in the product name.
You’ll find devices with both white and green phosphor in our night vision category.
Summary
- P43 = green, P45 = white phosphor. It’s the colour of the output screen, not the tube generation.
- According to the manufacturer there’s no lab performance difference; the choice is personal preference.
- What matters is comfort for your eyes during long viewing – try both if you can.
- In a binocular, and when pairing two devices, keep the same colour.
- Image quality is set by FOM, SNR, resolution and halo – check them on the datasheet.
Sources
- Exosens (Photonis): P43 (green phosphor) or P45 (white phosphor) – exosens.com (checked 9 Nov 2026)
- Exosens (Photonis): Night Vision one pager (P43/P45, FOM = resolution × SNR) – PDF (checked 9 Nov 2026)
- Exosens (Photonis): Difference between Gen3 and 4G (three-stage tube principle) – PDF (checked 9 Nov 2026)
- Exosens: ECHO & ECHO14 leaflet (P43 green, also available in P45 white) – PDF (checked 9 Nov 2026)
- Wikipedia: Phosphor – table of standard phosphor designations (P43, P45) – en.wikipedia.org (checked 9 Nov 2026)