Linear TIFF
Canon has included option to convert RAW files to so called Linear TIFF - images as CCD sensor sees them. These images on screen look very soft and dark and many users have wondered what is the point of having such an option. The answer is simple - if you think you can do better, Canon has given you the opportunity to start at exactly the same point they do in process of converting image from raw to it's final form.
Can you do better?
Many G2 users find no reason to challenge Canon's process. Canon has done very god job of generating results that will make most of the users happy most of the time. But, that everyday average is so often not good enough. You need to open your image in photo editing program like Photoshop and try to make most of it - recover shadow detail, try to bring back detail in blown highlights, make some "wrong" colors look right, have good sharpening without "white edges" etc. If you do not do this very often, then you probably wont find workflow presented here much useful. But it can, with some experience in image processing lead to results that will, in the end, simply look noticeably better.
What is linear workflow?
Idea is to start with image that is as close to CCD image as possible. You can do that by converting image to linear 16-bit tiff using converter based on Canon software (like Canon's Zoom Browser or very popular Breeze Browser) or using custom made converters like Rado's Power Shovel (please search Canon forum at http://www.dpreview.com to find more information about this and download location). You then load image into Photoshop or similar application that is "ICC aware" and assign appropriate ICC profile I created (depending on the converter used). If your image editing software has separate Working space (like Photoshop does), you must use working space with gamma=1. Now, you can edit image, do final resize, then final sharpening using even simple unsharp mask and then convert it to some other working space that is suitable for intended output device. As this sounds bit complicated (it actually is very simple once you set it up), my settings and workflow are explained here->.
Check results first
Each thumbnail on the right is a small illustration of differences between Canon results and my workflow. Canon workflow includes converting image to non linear 16-bit tiff with default options except sharpening set to low, resizing image to 1/4 and applying unsharp mask 100%, R=0.5, Threshold=1.. My process includes converting image using Canon converter to 16-bit linear tiff, assigning profile, setting black/white points, resizing to 1/4, sharpening using unsharp mask 150%, R=0.5, Threshold=1 and converting to AIM Native PC G2.5 profile.
First group of samples shows results of basic workflow with black & white points set as I felt was right for the subjects and with some increase in saturation - this is how I would normally process these images.
Two part image in the middle shows difference in sharpening - same amount has been applied to both version (500%/R=0.5/T=1 in full size) and then detail is shown in 200% magnification.
Third group of samples have just basic workflow applied and black and white points are set in such a way to illustrate details in shadow and highlights that exist in these images. No other processing is done so these samples offer good comparison of both color and image detail between these two workflows.
Credits
ICC profiles are built using XLProfiler developed by Timo Autiokari (http://www.aim-dtp.net) - extremely usable and precise tool. I cannot thank him enough for great effort and information provided on his site.
It's free
zz Canon G2 ICC Profiles are free. You may also freely distribute them with a reference to this page. They are provided on 'as is' basis with no support of any kind. I also cannot provide information and assistance in creating your own profiles or PS actions.
I hope you will find this profiles and sample workflow useful and enjoy using them. Download page is here->
Zoran Zivotic
zoran@zivotic.com.
