Both are laser projectors — but the light is created differently.
Laser phosphor typically starts with blue laser diodes. That energy excites a phosphor material which emits a broader spectrum of light; the projector then separates and controls the required colour components. RGB laser uses dedicated red, green and blue laser primaries, so the light source begins with three narrow-band primary colours.
Why RGB laser can reach colours that laser phosphor cannot.
The narrow spectral primaries of direct RGB laser can sit much closer to the outer boundary of the CIE colour diagram. That gives the projector the potential to cover a much larger gamut. Barco notes that RGB can reach the theoretical single-bandwidth Rec.2020 gamut, while conventional laser-phosphor systems generally work within a smaller triangle.
That does not mean every movie suddenly becomes more saturated. Most current cinema and home-video content lives largely within DCI-P3. The benefit is that a projector with a very wide native gamut can reproduce P3 without a light-sapping filter, preserve brightness at saturated colours, and provide headroom for content that uses colour beyond P3.
Colour gamut is only one part of image quality.
An RGB badge does not guarantee a better picture. Contrast, black floor, ANSI/intra-scene contrast, lens quality, panel/DMD alignment, processing, uniformity and calibration remain fundamental. Barco explicitly points out that its RGB models are designed as higher-performance optical systems as a whole; the light-source technology is an enabler, not the only cause.
Laser phosphor remains extremely compelling.
Laser phosphor makes high light output possible in smaller, more affordable chassis. It is mature, efficient and well suited to projectors such as Barco Njord or Epson's high-output Q-series where the design priority may be screen brightness, installation flexibility and value rather than absolute Rec.2020 coverage.
For many films, a well-calibrated laser-phosphor projector covering the intended content gamut can look superb. The choice should be tied to the target screen luminance, colour target and room — not prestige terminology.
RGB laser changes the engineering conversation.
Direct laser systems can introduce speckle: a fine granular interference pattern caused by coherent laser light interacting with the screen surface. Screen material, viewing distance, laser architecture and mitigation methods all influence visibility. A screen that is excellent with a broad-spectrum source may behave differently with narrow-band RGB lasers.
Metamerism can also become more noticeable. Two calibrated displays can measure similarly at standard colour coordinates yet look subtly different to different observers because narrow-band spectra interact with the human visual system differently. This is one reason experienced calibration and screen testing matter in flagship RGB-laser cinemas.
Brightness and colour volume are linked.
Wide gamut is most impressive when the system can also maintain useful luminance. A saturated colour at low brightness does not create the same visual impact as the same hue at high luminance. This combination of gamut and luminance is often described as colour volume.
That is one reason large RGB-laser projectors can be so striking on a big screen: they are not simply capable of different chromaticity coordinates; they can put substantial light behind those colours.
Heat, power and physical size still matter.
The most ambitious RGB systems can be physically large and thermally demanding. Freya and Freya+, for example, are cinema-class machines that reward a projection-room installation. RGB laser should therefore be evaluated as part of an architectural and mechanical system, not only on a colour-gamut chart.
How we would choose between them.
Further reading: Barco — RGB vs laser phosphor · Rec.2020, DCI-P3 and colour gamut