The whole picture at level 255 in red, green and blue. Compare the tint first: is one white bluer or yellower than the other? Then compare how bright the two are. Match these before you look at any color.
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White on both screensThe whole picture at level 255 in red, green and blue. Compare the tint first: is one white bluer or yellower than the other? Then compare how bright the two are. Match these before you look at any color.
Mid gray on both screens, level 128Red, green and blue all at 128, which gives about 21.6 percent of white's light on an sRGB screen. Two screens whose whites match can still differ here, in tint or in lightness, because gray depends on each screen's curve.
Gray row, five steps from black to whiteFive wide bars at levels 0, 64, 128, 192 and 255. On each screen all five should be plain grays with clear steps between them. Compare bar with bar across the two screens, starting with black in a dim room.
Red on both screensRed alone at full strength, the other two channels off. A red that leans orange on one screen and crimson on the other shows two panels with different red primaries. No brightness or temperature setting changes that.
Show all 20 patterns and checks (16 more)
Match patterns, in the order to use them, continued
Green on both screensGreen alone at full strength. Green gives about 72 percent of the light in white, so a brightness mismatch that white left in doubt shows here. A yellower or bluer green on one screen is a difference between the panels.
Blue on both screensBlue alone at full strength, the dimmest primary at about 7 percent of white's light. A night mode cuts blue, so if this field is plainly darker on one screen, check for that mode there before you blame the panel.
Six colors at full strengthRed, yellow, green, cyan, blue and magenta in six wide bars, every channel fully on or fully off. Yellow, cyan and magenta each light two channels at once, so they show whether the two screens balance their channels alike.
Six colors at half strengthThe same six colors with each lit channel at level 128, about 21.6 percent of its full light. Mid-tones follow each screen's curve, so two screens that agree at full strength can still part company here.
What differs between the two screens 6
One white is bluer than the otherThe bluer white has the higher color temperature and a yellowish one the lower. The sRGB standard used on the web puts a display's white at 6500 K, and a monitor's color temperature can usually be set in its own menu.
One white looks gray beside the otherWith the tints matched, the two screens still differ in light output. No web page can measure that, but on one flat field your eye compares the two directly: the dimmer white looks gray until the screens agree.
Gray has a tint on one screen onlyWhite matches, yet mid gray looks pink, green or blue on one screen. One of its channels follows a different curve between black and white. A correction profile made with a measuring device is the cure for that.
Mid gray is lighter on one screenWhites match but one gray is lighter: the two screens follow different curves between black and white, called gamma. Most computer displays aim at 2.2. Look for a Gamma entry in the menu of the monitor you are adjusting and move it one step.
Black is gray on one screenAn LCD filters a backlight and lets a little through at black, while an OLED pixel at black gives no light at all. Two such screens cannot share a black, and no setting closes the gap. Match the other four bars.
Colors are stronger on one screenThe range of colors a panel can show is its gamut, and devices differ in it. The narrower screen cannot be pushed further. Color-managed software uses each screen's profile to translate colors, so both show the same color wherever both can.
What to change, in order 6
The same picture mode on bothA picture mode swaps in a whole set of values at once. Put both monitors in the same kind of mode, the plain standard one if they share no other, and switch off any eco or dynamic contrast setting on either.
The same color temperature on bothSet both menus to 6500 K where they offer it, then compare white again. If the two still differ, leave the screen you trust alone and move the other's red, green and blue values a step at a time until the whites agree.
Brightness matched on whiteLower the brighter screen until neither white looks gray beside the other. An external monitor's brightness is set with the buttons on the monitor itself, so the operating system's slider may move only a laptop's own screen.
Night mode off on bothA night mode warms the picture by cutting blue, and it may not reach every screen: one system's help page says its night light is unavailable with certain display drivers. Switch it off, and automatic brightness too, while you match.
A color profile for each screenThe operating system keeps a color profile for every connected display: you pick the display, then its profile. Check each of the two. A profile left over from another monitor shifts every color on that screen and on no other.
Where matching by eye endsSettings bring two screens close. An exact match takes a colorimeter held flat to each screen: its software compares what was sent with what it reads and writes a correction profile for that display. Nothing on this page measures.
How this list was compiled: The patterns and notes are this site's own. Every color value was computed: a flat field is one color drawn edge to edge, the gray row is levels 0, 64, 128, 192, 255, half strength is level 128 of 255, and the light shares (21.6 percent for level 128, about 72 percent of white's light from green and about 7 from blue) come from the formulas and the luminance weights at https://en.wikipedia.org/wiki/SRGB. That color temperatures above 5000 K count as cool and bluish and those near 2700 to 3000 K warm and yellowish, that the sRGB standard stipulates a 6500 K display white point, and that monitor color temperature settings are usually tunable in the on-screen menu, is from https://en.wikipedia.org/wiki/Color_temperature. That most computer display systems decode with a gamma of 2.2 and that the desired gamma and color temperature are set with the monitor controls first is from https://en.wikipedia.org/wiki/Gamma_correction. That an LCD filters the light of a backlight and cannot show true black, while an inactive OLED element produces no light, is from https://en.wikipedia.org/wiki/OLED. That a color profile is made for each device and describes its gamut and color temperature, that profiles are used to translate colors between devices, and that the gamuts of devices differ in range, is from https://en.wikipedia.org/wiki/Color_management. That every output device has its own color signature from manufacturing tolerances and from deterioration through use and age, that a colorimeter is attached flat to the display and the software compares the values sent with its readings and creates a correction such as an ICC profile, or gives instructions for changing the display's RGB values through its on-screen menu, and that color perception depends on the ambient light, is from https://en.wikipedia.org/wiki/Color_calibration. That an external monitor's brightness is changed with the buttons on the monitor, that a night light shows warmer colors and is not available with certain display drivers, that brightness can change automatically with the light or the content, and that the color management settings set a default color profile for each connected display after you select the display, is from https://support.microsoft.com/en-us/windows/hardware/display-graphics/change-display-brightness-and-color-in-windows. That a color profile is chosen for a display in its Displays settings, with a recommended profile selected by default, is from https://support.apple.com/guide/mac-help/change-your-mac-displays-color-profile-mchlf3ddc60d/mac. That a night mode reduces some of the blue light of the display is from https://en.wikipedia.org/wiki/Night_Shift_(software). That some makers provide color profiles for their products, and that others are made with a colorimeter, is from https://en.wikipedia.org/wiki/ICC_profile. All read 2026-10-06. These are drawings to compare by eye. Nothing on the page is a measurement, and two screens matched here are matched by eye only. Licence: own work
How it works
This dual monitor image color test draws flat white, gray and color fields to show on both screens at once. Whatever differs between the two sits side by side: a bluer white, a brighter screen, a tinted gray, stronger colors.
Read the full guide
A dual monitor color test in four steps
1. Drag this window until the picture sits across the gap between the screens, half on each.
2. For a full view, open the page in a window on each screen and press Go full screen in both.
3. Start on white: match the tint, then the brightness.
4. Step through gray, the gray row and the colors. Change one monitor and leave the one you trust alone.
Match in the room light you work in: a lamp or a window on one screen changes how its white looks.
Questions and answers
Is there a test photo for making monitors match?
Yes. Save as PNG saves the pattern on show as a picture, made in your browser, at this screen's size, 1920 by 1080 or 3840 by 2160. Open the file full screen on both monitors, or set it as the desktop picture on each.
Why do my two monitors show different colors?
Every display has its own color signature, even two of one model: manufacturing tolerances and wear see to that. On top come settings that differ between the two and can be changed: picture mode, color temperature, brightness, night mode and color profile.
Should both monitors use the same color profile?
No. A profile describes one screen. Give each display its own, the one its maker supplies or one made by measuring it. A single profile shared by two different panels is wrong for at least one of them.