- Black crush compresses near-black tones; evaluate it with a patch pattern and appropriate gamma.
- On LG C1, B1 and G1, shadows can be recovered by adjusting the white balance point by point in SDR and HDR.
- Distinguish between black crush and artifacts such as macroblocks, bands, or fixed lines to avoid confusing problems.
- Take care with OLED usage habits to prevent image retention and maintain faithful Cinema or Filmmaker settings.
Sometimes, in your OLED screen or monitor The dark scenes look like a blank slate. That has a name: it's the famous black crushThis phenomenon causes textures to be lost in shadows and dimly lit objects to disappear.
In practice, the tonal range close to black is compressed and no longer shows nuances that do exist in the signal. Fortunately, There are ways to avoid black crush, or diagnose it with simple tests and reduce it in many models by adjusting the image or, if necessary, calibrating.
What is black crush and why does it occur on OLED?
Black crush is a problem as common and irritating as... burn-inIn this case, it's about the loss of detail in the darker tones. It's not that black ceases to be black, but rather that The levels close to black are grouped together and they cease to be different.
This can be done intentionally: some manufacturers prefer to hide artifacts typical of compressed content, such as banding, posterization, or noise, and to do so, they stiffen the curve at the lower end. There are also monitors that adjust their curve in this way to minimize chromatic overshoot, that is, small color overshoots around very dark transitions.
In practice, you'll see that night scenes or dimly lit interiors lose micro-details: folds in black shirts, textures in asphalt Or corners of rooms become blurred. This happens a lot in stores because demonstration modes are often not the most accurate, and ambient lighting exaggerates the perception of contrast. That's why, when comparing an OLED to an LED next to it, the LED appears to show more shadows when the OLED isn't displaying correctly.
How to test if your screen has black crush
The most direct way to detect and avoid a black crush is use a pattern of patches of shadows very close to black. It is a grid with squares ranging from absolute black to several levels just above. In this test, the visibility of the first squares It tells you how the area near black is responding. There's an important nuance with gamma: in Windows, the default setting is usually sRGB gamma; in that case, each square will be more easily visible.
If you force or configure a flat gamma of 2.2, which is the SDR standard in many environments, the correct thing to do is the first two or three patches are indistinguishable of black at a normal viewing distance. If in your case the first five or eight patches are completely invisible, you have moderate black crush. If even more patches disappear, the crush is clearly severe. On different monitors and televisions, this can vary with the overall brightness control, so note the model and check if the number of visible patches changes when you raise or lower the brightness level.
Keep in mind that some platforms or networks may compress or alter test images. If you suspect the test image has been modified by compression, try viewing the pattern from an original source or upload the file locally so that the panel interprets it exactly as written.
OLED vs. LED in store: when blacks are too black
Next to the LED, the OLED It seems to leave everything in total darkness. For example: in a scene with puddles or shadows in a corner, The LED allows for hints of reflections and textureswhile the OLED displays nothing. The same thing happened with a black shirt: in the LED Wrinkles are visible on the screen, but they fade away on the OLED display.
This doesn't mean OLED is worse. It's usually the settings and the environment that work against it. Fluorescent lighting from above, demo picture modes, and a lack of adjustment time can make OLED appear darker in shadows. With a suitable picture profile and a correct calibration of the gamma or from the EOTF, OLED must recover those nuances without losing its advantage: authentic blacks and infinite contrast pixel by pixel.
Gamma, sRGB and the patch test: interpret what you see correctly
An important note about patch testing: In Windows desktop environments, it is common for system management to lead you to an sRGB color space.Under this behavior, patches near black open up more, and you might be able to see all the squares of the pattern. This doesn't mean your panel is perfect; it simply means the sRGB curve adds a slight attenuation in shadows that enhances the visibility of micro-details.
When using a flat gamma of 2.2, which is the common reference in SDR, you should expect the first two or three frames of the pattern to be indistinguishable from the usual viewing distance. If, under those conditions, you can't see the first five or eight frames at all, it's a clear indication of moderate black crush. Also note how global brightness changes They alter the result, because according to the panel's electronics, increasing the brightness can further open or close the lower zone.
And if you're unsure whether the pattern you're using is intact, avoid reproducing it from a site where it might be compressed or altered. Ideally, use a local file or a trusted source so that Don't be fooled by the codingAnyone curious about blacks in HDR can make a parallel comparison: the PQ is absolute and any deviation in the first nits is noticeable very quickly.
When HDR looks dark: a typical case on monitors
Some OLED monitor users have reported that in modes like HDR1000, everything appears excessively dark, to the point that anyone entering the room would notice. This aligns with a black crush effect intensified by the monitor's tone mapping and how... The EOTF PQ continues to follow the reference in the lower zone, and in many cases Your monitor's HDR may be worse than SDR. If, in addition, the monitor's HDR mode is aggressive with the curve, it's normal for the shadow areas to be very sunken.
In these situations, it's advisable to review the selected HDR mode and its shadow handling. Not all panels offer fine-tuning in HDR by spot adjustments, but any control over black levels or near-black shading helps alleviate the situation. When spot white balance is available in HDR, the guidelines of slightly raise the first steps In nits they usually give air without creating a veil in blacks.
Macroblocks, bands and lines: not everything dark is black crush
Not all anomalies in dark scenes are the same. One user with an LG OLED B8 described nighttime scenes with brighter vertical bands on the left side at specific times, in addition to two horizontal lines always visible in the same place. This fixed pattern of bands or lines suggests uniformity or processing problems, which They do not behave like typical macroblocks of video compression.
Macroblocks are large blocks that flicker or light up irregularly in compressed areas, especially with low bitrates and in difficult shadows. What was being described, on the other hand, were lighter areas that did not flicker and stable lines, something closer to banding or a panel signature. In workshops, if the dark scene is not reproduced exactly and the room is not dark, It's easy for the technician to miss it.That's why it's crucial to note the exact minute and content and carefully adjust the television before drawing conclusions.
If you encounter something like this, start by thoroughly configuring the image, choosing a faithful mode, and checking for any edge enhancements or smoothing that might introduce unwanted side effects. A frame-by-frame comparison with another source can help determine whether the issue lies in the file or the panel. Sometimes, with a good setup The perception of bands is significantly reduced in real content.
OLED with very black in cinema but with texture: how to balance expectations
That an OLED delivers pure blacks is a virtue. The goal isn't to increase the black to see gray, but to preserve pure black while also recovering the first few shades of shadow. Therefore, when adjusting settings, make sure that the 0 percent brightness tests remain black in total darkness and that minimal patches or close-up details reappear. The right point is to reveal texture without turning the image into a wash.
When comparing to LED, it's important to understand that light haloing and black lift can give the impression of more detail in shadows when in reality it's just a slight veiling. With a well-tuned OLED, the fine detail should be there. If you're choosing between models like the A80K and an LED alternative like the X90K, keep in mind that with a correct film profile and gamma OLED can show that crease in the shirt or that shine in the puddle without sacrificing its absolute black.
Precautions regarding retention and burn-in on OLED
OLEDs are sensitive to static images displayed for extended periods. Network logos, news graphics, video game scoreboards, or interface bars can all leave marks. Therefore, in addition to properly adjusting the image and resolving black crush, Prolonged static positions should be avoided and let the panel maintenance cycles do their job when the TV indicates it.
If you notice shadows or image retention, follow the manufacturer's guidelines to reduce them. Maintaining reasonable usage habits and avoiding excessive viewing of content with static elements at high brightness helps keep the panel in good condition. Often, this is all it takes. vary the content or activate routines pixel refresh rate so that those fingerprints fade over time.
Quick tips to minimize or avoid black crushes without complicating things
For those who want a quick improvement without getting into point-by-point adjustments, a few simple recommendations can make all the difference. Choose picture modes like Cinema or Filmmaker, disable aggressive processing, and adjust the black level or brightness so that the pattern shows at least the third or fourth patch When using gamma 2.2, try to keep the room lighting controlled so that the perception of shadow is consistent.
On the LG C1, B1, and G1, if you're up for using the 22-point white balance, apply the suggested increases to the low levels, in both SDR and HDR. You'll see how hidden textures reappear without ruining the contrast. And remember: if you're looking for absolute precision, a probe calibration It aligns the screen with the reference and ensures a clean trace in blacks.
In summary: avoiding black crush is relatively simple if we evaluate it against a reliable standard and understand the difference between sRGB gamma and a flat 2.2 aperture. With well-measured adjustments in the near-black area, even modifying the white balance by individual points on models like the LG C1, B1, and G1, it's possible to recover shadow detail without raising the black levels. If you also distinguish between compression artifacts, banding, or static lines, and are careful with your usage to avoid image retention, Your OLED screen will bring back the cinema experience as it should be seen.with deep blacks and fine texture where it matters.
Editor specialized in technology and internet issues with more than ten years of experience in different digital media. I have worked as an editor and content creator for e-commerce, communication, online marketing and advertising companies. I have also written on economics, finance and other sectors websites. My work is also my passion. Now, through my articles in Tecnobits, I try to explore all the news and new opportunities that the world of technology offers us every day to improve our lives.