![]() 16 bit has a lot of advantages, particularly if you also set color mode for prophoto, in that you can do a lot of adjustments and still not end up with a spiked histogram. After adjustments in acr you then open in ps so it ends up whatever you set acr for. When the raw file is demosaiced in acr, the options (the link at the bottom in acr) sets whether 8 bit or 16 bit, which color space, and resolution. Photoshop CS5 will allow you to select JPEG even if the current image mode is 16bit, CS4 will require the current image mode to be 8bit before you get the option to save. Ooooh forgot to mention this only affects Photoshop CS4 and earlier. It still processes all layers in 16bit and then downconverts the final result. The Save For Web and Devices dialogue has the same effect. If you flatten the image in 16bit, the calculations are done one final time in 16bit and your conversion to 8bit doesn't have any effect since all visible colours in the sRGB gamut can be represented in 8bits. If you process this image in 16bit, and then convert to 8bit, all those calculations done to display your final image revert to 8bit. However on an image with layers, what you see on the screen is the mathematical result of all of the layers you have on the image. There's no calculations going on to display the final image, and it's just showing the layers. What you see on the screen is what you get. The position of these sample values in hex code would be at 0x1E248 to 0x1E24A ( * + = 1280*96+584.585.586).On a flat image it makes no difference. row 96 and column 584 to 586, we can check if the bytes in the. If we take some sample values from the image e.g. The converted image will look like figure 5 left. ![]() (type –help for more information)įig 5: original image (left), crop (right) The output format can be chosen as you like, in this case we choose TIF. raw extension does not specify a known format and has no header information. The “Explicit Image Format” GRAY identifies our image as a grayscale image, because the. The executable “convert.exe” needs some flags: ImageMagick maintains simple command-line processing for converting raw files. After that, the images can be saved in any supported format.įig 4: ImageMagick convert via comandline raw files include a header you can choose an offset of several bytes to get access to the image data. In Photoshop we have to enter the amount of channels in a separate edit field, whereas in ImageJ the pop-up menu “Image type” combines the bit depth and amount of channels. ![]() We have to enter the image dimension and the bit depth. The conversion via Adobe Photoshop and ImageJ is similar. As already mentioned, our file is a 1280x800 grayscale image (8 bit).įig 2: Adobe Photoshop raw fig 3: ImageJ raw import raw files two things must be known: the width and height of the image and the bit depth. There are many different ways to convert bit-stream images, we would like to present at least three. Because the counting starts at 0x00000, the last value 03 is at position 0xF9FFF (which is 1.023.999 in hexadecimal form). In the editor the file is represented by 1.024.000 (=1280*800) hexadecimal values. raw file opened in a hex-editor would look like the following. Because there is no additional information, each byte represents the gray value of one pixel. CR2, NEF, ARW, ORF, RAF etc.).Īs a sample image, we consider a 1280x800 grayscale image (8 bit). raw file contains only information about the image pixel values, there’s no header and no additional information included (in contrast to the camera raw files e.g. In this case we define a raw image as a series of bits. In this TechNote we would like to present three ways to convert a raw (bit-stream) image into a conventional image file format. ![]()
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