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photo:image_workflow

RAW image processing workflow

Introduction

  • the first step to great image quality is getting it as right as possible in the camera:
    • focused correctly with the desired degree of depth of field (DOF)
    • minimal camera shake and subject blur by choosing an appropriate shutter speed, image stabilisation and/or a tripod
    • minimal image noise by using as close to the camera's base ISO as the above will allow
    • correct white balance as this will impact your camera's exposure metering
    • correct exposure for your desired needs
    • and of course you need to shoot in RAW mode for best results in post-processing as these are 12bit or 14 bit tones per color channel not just 8 bit (256 values) as are jpegs
    • now how you actually decide to take the photo may be informed by your knowledge of what you can do in post-processing so this is an iterative life long learning process - for instance you may decide to take multiple photos to reduce noise, or create a HDR, or to remove moving subjects, or to create greater DOF by focus stacking
  • ideally, your computer should be colour calibrated so you see what you get properly
  • once you decide on which image to use, it must be imported into an image editor that supports the RAW file you are using (newer cameras have newer RAW file versions and may not be able to be used in older image editors - in this case you either need to update the image editor or use another image editor to convert the RAW file into either a universal RAW file format such as DNG or into a 16 bit TIFF file)
  • RAW development
    • a RAW file needs to be “developed” into a color space (eg. sRGB, AdobeRGB, or ProPhotoRGB) and rendered and it is here that you can set the base image qualities by altering various components (see below)
  • Image editing and adding effects
    • further tonal adjustments to the whole image such as applying a LUTs color scheme, split toning, conversion to monochrome, etc
    • you now tweak your image by performing tonal adjustments to areas, local sharpening/clarity/etc and remove annoying blemishes.
    • one may consider cropping the image and rotating it to straighten horizons, etc
  • Finalisation of image
    • this involves removing noise and adding sharpness as needed although this may have been done in the RAW development phase in some editors
  • exporting the file
    • you need to decide on what file format to use, and the final image size and quality.
    • if printing, you may decide upon a 16 bit TIFF file in AdobeRGB
    • if web display you should be using sRGB and possibly a jpeg file or PNG file to reduce file size

Exporting as jpeg

  • minimising file size but maintaining best quality:
    • image noise will increase jpeg size, so de-noise it first
    • a highly detailed image with lots of fine detail will have a very large file size, so consider adding a Gaussian blur first
    • select the output file size - usually 1200-2400 pixels for the long side if using it for web display
    • select the quality level - perhaps something around 85-90% is a good compromise for quality jpegs
photo/image_workflow.txt · Last modified: 2019/07/17 14:54 by gary1