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Photoshop convert to 8 bit8/30/2023 ![]() *don’t imagine that selecting maximum quality for your Jpeg is preserving the original data, it's still compressing a lot which discards information. 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. Some people say it’s important to sharpen while still in 16-bit, though I've never seen any evidence to support this. You could resize before flattening, for example. Why? Any edits to size or crop, or even just re-saving a Jpeg file means further compression, potentially that’s very damaging. Crop/resize Convert to 8-bit Sharpen Save Now, the order of some of those steps is flexible. 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. Attached is the ISIS image that was printed to get the measurements.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'. By doing this this at the start of your work, any edits you make to. The blue line is without "dither" checked, Orange is with. Simply head to Image -> Mode -> 16bit, to convert your Photoshop document to a 16 bit file. I have never seen this impact a print visually but if it does, it is most likely to show up in deep shadow areas with smooth, non-noisy gradients.Įdit: Added plots of measured L* for RGB values ranging from RGB(150,150,150), RGB(150.125,150.125,150.125), RGB(150.375,150.375,150.375). Most of the printer space is only affected. Dithering will produce slightly more accurate printing, roughly similar to that produced by a true, 16 bit printer driver. For instance if one wishes to print the Cyan value Lab (50,-70,-20), the result after printer profile conversion will have fractional components. ![]() However, the dither option does affect 16 bit images already in device space if they have fractional parts not accurately represented in 8 bits.Īnd it also affects printing of specific colors. This has no affect on profile targets because their fractional parts are 0 and are already in device space. The dithering occurs when the driver space RGB values have fractional values such as RGB 100,110,120.3, in which case the printed pixels will be varied between 100,110,120, and 100,110,121 so as to average out the fractional part. This is because the image, after conversion to printer space, is always 16 bits. When that option is selected in Edit->Settings, printing to 8 bit printer drivers is dithered. Further, when printing it affects both high bit and 8 bit images. Even though it is not listed as an option in the printer dialog. I just found out, via measurement and noticing unexpected results, that it also affects images when printing. That makes sense when you consider the conversion errors with 16 bit images are on the order of. When converting colorspaces the "dither" option only shows up with 8 bit images and is grayed out, unchecked, with 16 bit images. ![]() This is a small effect even going from ProPhoto RGB to sRGB. I've long assumed, incorrectly, that the "Use Dither in 8 bit/channel RGB images," a global setting in Edit->Settings, only sets the default conversions between different colorspaces with 8 bit images as a way to minimize banding. ![]()
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