This is almost never the case if you use a mobile phone or a retina display. To compare a dithering to a blending you need to look at images at 100% scale so that every single pixel of the image occupies exactly one pixel of a screen. If you use any decent image editor then most probably you are safe and a gamma correction is enabled by default. So I advise to always use a gamma correction. As you can see the first one is very different to other two (If you don't see it, read the notes below). Let's finally compare the blending of opaque red and blue with alpha of 0.5 where the effect of a gamma correction is maximum.įirst image does not use a gamma correction, the second one uses a gamma of 2.2, and the third one uses a dithering. So gamma is very important thing for blending especially when opacity is close to 0.5. We literally blend them by mixing like aquarelle in this example. And this is what you probably expect from blending two colors. The result looks much closer to image with gamma = 2.2 in terms of lightness and transition colors. The image contains pixels of just two colors but a probability of blue linearly increases from 0 in the left to 1 in the right. Last gradient is built using a dithering. If we use a gamma correction then the transition and the lightness become much more smooth. There are clearly darker colors in the center. Let's enable a gamma correction and do the same (gamma = 2.2)Īs you can see there is much more localized transition if we don't use a gamma correction. Now let's blend them without a gamma correction (gamma = 1) Let's take first one fully opaque and set an opacity of the second image equal to x-axis like this Here is an example why a gamma correction is important for the blending. Historically it was introduced to compensate a non-linearity of CRT displays. Almost every RGB space that is used today interprets color components in a non-linear way in order to place more color information in 8 bits. The reason to include a gamma correction into the formula is to move components into linear space on calculating. More accurate one would be Y = (255^G * (1 - P) + X^G * P) ^ (1 / G) where Y - resulting RGB component value, X - overlay RGB component value, P - its opacity, G - a value of a gamma. Please note that the suggested formula Y = 255 - P * (255 - X) is not quite accurate due to a gamma correction. Specifying the opacity as a decimal fraction.
Or you may use it like this blec white deadbe:0.75 Last ef is the hex representation of an alpha channel. If you want it to be completely transparent, set the alpha to 0.For your specific case you may use it this way blec white deadbeef If you want a solid background, the opacity, or the alpha value, should be set to 1. Alpha is used to determine how opaque your shade should be. Red, green, and blue values represent the amount of each color used to create your desired hue, but the alpha is what we’re going to focus on. Fortunately, there is another solution. It’s easy to make the background of any HTML transparent by defining the element’s background-color property using RGBA. This is because the opacity property will select both the background and the text to make them less opaque. If you have a tag positioned over an image, for example, and you want to give that element a white background to make it more visible over the image, but you want that background to be a bit transparent so you can still see the image underneath it, opacity won’t help you. CSS’s opacity property is great for making any HTML element (especially images) see-through or transparent, but the problem with the property is that it applies to the opacity of the entire element.
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