Blue Screen
Fills the whole screen with blue, #0000FF, and holds it there. It is a flat block of color for whatever needs one: a backdrop, a color reference, or a quiet thing to leave on a screen you are not using.
This is a page that turns your screen blue on purpose. If you arrived looking for help with a Windows crash screen, this is not that - your operating system's own support pages are where to start.
Press Esc at any point to come straight back to this page.
What a blue field is useful for
- Chroma key, when green is the wrong choice. Blue was the original film standard and is what productions still fall back to against green clothing, foliage or blond hair.
- Checking a display's blue channel. A full blue field is the strongest signal your blue subpixels will ever get, which makes a dead one, a patch that shifts purple, or a panel with an obvious cast easy to spot.
- Giving a camera or a scanner a large, evenly lit block of a known color to look at, when you want to see how it handles saturation.
- As a plain background: behind a small object being photographed, on a monitor in the corner of a set, or as something calmer to look at than a desktop full of icons.
Blue as the chroma key alternative
Green is the default because sensors resolve green best and skin contains little of it, but green fails the moment the subject is wearing green or standing in front of a plant. Blue is the classic answer to that, and it also holds up better around blond hair, where a green background tends to tint the fine edges. The trade is noise: the blue channel on most sensors is the weakest of the three, so a blue key needs more light on the background than a green one to stay clean. The same warning applies as on the green page - a monitor is a glossy light source, so kill reflections, keep the subject off the screen where you can, and light them from the front.
Blue light, without the marketing
Blue is the shortest wavelength your display emits, and there is genuine research into how evening light affects sleep timing. There is also a large industry selling glasses, filters and settings on the back of it, and the evidence for those products is much thinner than their advertising suggests. What can be said plainly: a bright screen close to your face at night is more light than a dim one, this page is a bright screen at its most saturated blue, and if you are using it for a long time in a dark room the sensible move is to turn the dimmer up. We are not going to tell you it does anything to your eyes or your sleep beyond that, because we do not know, and neither does anyone selling you a filter.
For most subjects green is still the easier key, and on a wide-gamut display it can reach a purer color than sRGB allows. Use the green screen instead
Sources
Frequently asked questions
Is this a blue screen of death?
No. This is a web page that fills your screen with the color blue and does nothing else. There is no error text, no progress counter and nothing pretending to be an operating system. Press Esc and you are back on this page.
What blue is this exactly?
Pure sRGB blue, #0000FF: the red and green subpixels off, the blue subpixel at full. It is the most saturated blue your display can show without going outside sRGB, which is what makes it a useful test signal and, frankly, a slightly harsh color to sit and look at. If you want a softer blue, the custom color page takes any hex value you type.
Should I use blue or green for my key?
Green unless something in the shot is green. Green gives your software a cleaner, less noisy channel to work from and needs less light on the background. Switch to blue when the subject wears green, stands near plants, or has fine blond hair that a green background is tinting at the edges.
Can I make it darker?
Yes, with the dimmer on the screen itself. It lays black over the color at whatever opacity you set, which is the only kind of dimming a browser is capable of - no web page can reach your hardware brightness. For a deeper change, turn your display brightness down as well before you open it.