![]() So far, we have been only talking about grayscale images, but when it comes to color we are looking at even more significant numbers of colors available in digital images.Įach color in a digital image is made up of the three primary colors – Red, Green & Blue. The other aspect is how broad a range of colors can be expressed – the gamut, but that’s a topic for a separate article. ![]() ![]() The higher the number of bit depth, the higher the number of possible colors available in the image. Bit depth or color depth is only one aspect of color representation, expressing how finely levels of color can be expressed (a.k.a. color precision). We know 1-bit color depth (2 1 = 2 colors) as monochrome, it is just pure black and white pixels. If we look at a grayscale 8-bit image, even though there are no other colors but black and white again, there are 2 8 = 256 possible shades of gray, in other words, 256 different intensity values of each of these colors, that can be used in the image.Īnd in the same fashion in a 10-bit grayscale image there are 2 10 = 1,024 possible shades of gray between black and white, and in a 24-bit grayscale image there are 2 24 = 16,777,216.īit depth represents the total number of colors a digital image can contain. Think of it as Color Depth.īit depth is the number of bits (0’s and 1’s) used to indicate the color of a single pixel. Images with higher bit depths can display greater range of colors, since there are many bit combinations available per pixel. ![]() This is not to say that the image will make use of all the colors in the palette, but they can be used to specify necessary colors with a certain level of precision. *don’t imagine that selecting maximum quality for your Jpeg is preserving the original data, it's still compressing a lot which discards information.Bit Depth is a metric of how many unique colors are in the color palette of an image that are used to represent each of the colors. That’s when you’ll see a jpeg with some real issues. The jpeg damage is not always immediately apparent, which is perhaps why it's still widely used - however, the compression will soon cause issues if you do further work and save again. Why? Any edits to size or crop, or even just re-saving a Jpeg file means further compression, potentially that’s very damaging. Jpeg compression (at any setting*) really is "lossy”, irreversible and cumulative, so should ONLY be used only for final delivery AFTER resizing & cropping to the FINAL size and crop. J peg is the worst possible format if you want to keep high quality - you should always archive a copy of your original, with adjustment layers intact - if that’s how you work. Jpeg is not OK for archiving or for any file that may need to be resized or cropped down the line. Like Digitaldog I'd do the resize manually and perhaps ad da bit of sharpening (unsharp mask)ġ: archive that edited original (with it's adjustment layers) as a master copy, full size, 16 bit, ProPhoto.Ģ: make a copy, convert to sRGB (probably best to do this whilst still in 16 bit)ģ: resize to the right pixel dimensions for the relevant site.ĥ: 'Save as' a Jpeg, I prefer'Save as' to 'save for web' or 'export'.
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