Subpixel Zoo: A Catalog of Subpixel Geometry
An image pixel might be a little square with a flat color[1], but to actually present the image on a physical display (or related technology), we illuminate discrete 'subpixels'. The perceived color in an area is then the addition of the subpixels' emissions in that area.
Working in graphics (where knowing the particulars of such things is sometimes important) has brought my attention to the fact that there are both a huge number of arrangements of subpixels and no centrally located database describing them. Wherefore, I decided to categorize and name them myself.
This page intends to exhaustively list all subpixel geometries that are used in practice. They are drawn procedurally by the same program. When possible, I provide an outline describing each pixel (in some cases, multiple pixels must be outlined to show a tileable pattern). Click on any for a larger image. Relevant links[2] and example products are also provided for some patterns.
If you have verifiable evidence (e.g. a microscope image) of a screen with a subpixel geometry not listed here, or spot an error, please contact me (options on main page) to let me know! You can also help contribute by adding new (or not implemented) geometries to the program directly.
If you know your display is RGB, BGR, VRGB, or VBGR, you can disambiguate which with a test image.
Technical Overview
Figure 1
: Red, green, and blue subpixels in the "RGB" subpixel layout combine to give the impression of white at a distance.Image Pixels, Screen Pixels, and Resampling
The simplest way to present an image is to assign exactly one red, one green, and one blue subpixel in the screen to each incoming pixel from the image. For example, in Figure 1, typical of LCD monitors, each image pixel (cyan) maps onto a red, a green, and a blue subpixel. The RGB values from the image pixel are simply copied as the subpixels' illuminations.
Figure 2
: Triangular subpixels break the direct relationship between image pixels and screen subpixels, and can only be described by resampling.However, there is not always a direct correspondence between image pixels and screen subpixels. Triangular grids, as in Figure 2, are typical of CRT displays such as old monitors and televisions[3], and show up occasionally in modern LCD displays too. CRT monitors are commonly described as having no native resolution[4][5]. The rectangular image data is scanned out, and whatever subpixels in the triangular grid happen to get touched as the beam moves along are the ones that light up (potentially partially, depending on how exactly the beam hits them).
This is a resampling operation[6]. There is no simple relationship between the incoming image data and the resulting subpixels that get touched. In particular, one image pixel might cover multiple, one, or less than one phosphor clusters—it is not a direct mapping.
Do we call the triangular clusters of subpixels 'pixels' as well? The answer should be yes; a pixel is a 'picture element', and the combination of these clusters indeed makes up an image. And what else could 'subpixels' form but a 'pixel'? However, we have to understand that these screen pixels are not in a rectangular grid like the incoming data, and indeed, they don't even have to be square. For this reason, it isn't very common to refer to them as 'pixels', and when done it tends to confuse everyone involved.
Figure 3
: PenTile arrangements have half as many red and blue subpixels as green, and so on average have two subpixels per image pixel, increasing effective resolution.PenTile Displays
Most displays today are in mobile phones, and most phones use some variant of a 'PenTile' matrix. These displays have twice as many green subpixels as red and blue, but also image pixels map onto only two subpixels each, on average, with neighboring pixels counting for the subpixels of the other color.
The point of this is that pixel density is higher (image pixels map onto two elements instead of three, so they don't need as much room). Because green is most perceptually important and contributes most to luminance[7], it makes sense that each pixel always has green, while red and blue as less important, and so can be subsampled[8].
It is not always clear exactly how an image pixel is displayed by screen subpixels in a PenTile screen[9]. I have found only a few sources, and these seem to be incorrect or incomplete[10]. I suppose there are the original patents[11], which I assume are useful for lawyers, which I'm not.
Fortunately, in some cases, notably the common Diamond PenTile pattern (Figure 3 and also in the zoo), I have been able to figure it out through experimentation with crafted test images and microscopes[12].
Filter Arrays in Cameras
Sensors in the photography and display world are made of little elements called 'sensels' (from 'sensor element') or 'photosites'. These sensels may have color filters over them, limiting what wavelengths of light they respond to. An arrangement of sensels is called a 'color filter array' (CFA), and in the common case of the arrangement comprising red, green, and blue filters, the CFA is also called a 'Bayer filter' (pronounced [ˈba͡ɪ̯ˌəɹ]: BYE-er). This usage is sometimes inconsistent in the real-world, with non-Bayer CFAs erroneously being called Bayer.
There are two basic ways for sensels to reconstruct an image:
- In a classic CFA, each sensel corresponds 1:1 to a pixel. Since a sensel can only provide a single channel at the pixel, the missing color information is interpolated from neighboring sensels, in a process called demosaicing.
- The other way is for groups of sensels to be grouped together into a single pixel, much like classic subpixels and pixels for displays, but in reverse.
It is sometimes difficult to determine which of the two options was intended from camera descriptions.
The Subpixel Zoo
The subpixel zoo follows. Please note that the elements in the zoo are subject to recategorization and correction without notice.
Square Geometries
| Name | Geometry | Notes | Known Products | References |
|---|---|---|---|---|
| Basic |  | The model most people think of for pixels: a small square where the color is represented everywhere. Incorrect, since no display technology actually does this. | ||
| RGB | | Arrangement with three subpixels per pixel. Most common type of LCD monitor. | ||
| BGR |  | Same as RGB, except horizontally reversed. | Google Nexus 4 | |
| Alternating RBG |  | Reverses red and green every other row, with blue apparently sandwiched in the middle. Hard to tell which way the first pixel is, whether blue is indeed in the middle, and whether any such arrangement is used in real products. | ||
| Chevron RGB |  | Same as RGB, but subpixels are chevron-shaped, presumably to widen useful area. | Dell TFT LCD 1905FP | |
| Quattron RGBY |  | Adds a yellow subpixel to create a second luminance peak within the pixel region (as well as to better display yellows). The manufacturer claims this effectively doubles the perceived resolution, though since the content resolution doesn't change, that seems suspect to me. | "AQUOS XU" series TVs | |
| RGBY (Shifted) |  | An improved version of Quattron RGBY that takes PenTile-style undersampling ideas. It seems like multiple pixels can contribute to some subpixels. | ||
| VRGB |  | Same as RGB, except rotated. | ||
| TiltVRGB |  | Tilt subpixels of VRGB so that they interleave. (Pixel footprint is a guess.) | ||
| VBGR |  | Same as RGB, except rotated (the other way). | Sony R510C Sony W650D Steam Deck | |
| S-Stripe RGB |  | Arrangement with three subpixels per image pixel, with the blue subpixel being elongated. | Samsung Galaxy Note II | |
| Alternating S-Stripe RGB |  | Same as S-Stripe RGB, except the pattern flips horizontally every row. | ||
| Shift S-Stripe RGB |  | Similar to S-Stripe RGB, except the blue subpixel shifts and the red/green subpixels are swapped. Can produce fringing on the top and bottom of text. | Samsung Galaxy Tab S 10.5 Nintendo Switch OLED ThinkPad P14s | |
| XO |  | Arrangement used by OLPC devices in color mode. Each pixel maps to one subpixel (see diagram). | OLPC XO-1 OLPC XO-4 (likely the rest too) |
PenTile Geometries
| Name | Geometry | Notes | Known Products | References |
|---|---|---|---|---|
| PenTile Prototype |  | A diamond blue pixel bordered by four triangles. This may just be a prototypical PenTile pattern. | ||
| PenTile (Alternating) RGBG |  | Classic PenTile matrix. Each pixel contributes to only two subpixels, allowing for thinner features. | Google Nexus One Samsung Galaxy S3 Samsung Galaxy Nexus | |
| PenTile (Alternating) RGBW |  | Classic PenTile matrix with white. Orientation varies. | Samsung Galaxy Note 10.1 | |
| PenTile Diamond | | A version of PenTile they call "Diamond". Many internet resources are wrong; after an immense amount of experimentation, I finally figured out observationally how pixels map onto subpixels: the red and blue are shared. | iPhone 12 Pro Max iPhone 15 Pro Samsung Galaxy Note 3, 9 Samsung Galaxy S23 | |
| PenTile Diamond (Orthogonal) |  | The PenTile Diamond arrangement rotated to be axis-aligned. Again, it is not clear which pixels are touched. | Samsung Galaxy Tab S 8.4 |
Filter Geometries
| Name | Geometry | Notes | Known Products | References |
|---|---|---|---|---|
| GRBG (Bayer Filter) |  | Similar idea to PenTile Diamond (Orthogonal). | ||
| WRBG (CFA) |  | |||
| CRBG (CFA) |  | Same as GRBG (Bayer) with one of the greens replaced by cyan ("emerald"). | ||
| CYGM (CFA) |  | Arrangement using different primaries. The advantage is higher quantum efficiency of the filters. The disadvantage is loss of color fidelity. | ||
| CYYM (CFA) |  | Another arrangement using different primaries. See also CYGM (CFA). | ||
| Kodak RGBW 4a (CFA) |  | RGBW components arranged in a 4x4 square. Filter supposedly used by Kodak. | ||
| Kodak RGBW 4b (CFA) |  | RGBW components arranged in a 4x4 square. Filter supposedly used by Kodak. | ||
| Kodak RGBW 4c (CFA) |  | RGBW components arranged in a 4x4 square. Filter supposedly used by Kodak. | ||
| Fujifilm X-Trans (Bayer Filter) |  | Arrangement claimed to be more resistant to Moire patterns. | ||
| Fujifilm RGGB EXR (Bayer Filter) |  | Filter with color channels arranged in stripes. Pixels can be defined as the combination of adjacent photosites, or as overlapping RGGB filters. See reference. | ||
| Alternating RGWRGB |  | Strange filter used in some cameras. | Samsung Galaxy (Camera) |
Triangular Geometries
| Name | Geometry | Notes | Known Products | References |
|---|---|---|---|---|
| Horizontal Column Dot |  | Triangular grid of phosphors. CRT examples tend to be perfect circles. Note rectangular input gets resampled! | RG280M (?) | |
| Horizontal Column (Square Grid) |  | Like Horizontal Column Dot, but with the rows spaced a little more so that the diagonals become 45°. This means there is less resampling in the vertical direction. Not clear where the pixel boundaries go, though. | ||
| Vertical Column Dot |  | Triangular grid of phosphors. Note rectangular input gets resampled! | ||
| Vertical Column (2:3 Grid) |  | Triangular grid with a 2:3 ratio of tiling pixels. | ||
| Vertical Column Horizontal RGB | | Triangular grid of pixels that can be thought of as shifting alternate columns of a rectangular grid. Each cell then has three vertical RGB elements like basic RGB. The cell size can vary as well; e.g. the Wikipedia example has shorter cells. Note rectangular input gets resampled! |
Additional Credits
- Gleb Mazovetskiy reported the Horizontal Column (Square Grid) geometry.
- Brendan Weibrecht reported the Vertical Column (2:3 Grid) geometry for LCDs.
- Vlad Negru for links sourcing the Sony R510C, Sony W650D, and experience with the Steam Deck and photo, as VBGR.
- Praveen Pathak for investigations into diagonal PenTile.
- Patrick Gillespie for photo of iPhone 12 Pro Max subpixels (and pointing to iPhone 15 Pro).
- User 'cyrozap' on Libera IRC provided photos of Shift S-Stripe RGB, listed several products, commented on how they render text.
- Doug Dingus, on the Samsung Note 9 having PenTile Diamond.