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Old Sep 10, 2009, 7:48 AM   #11
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Keep in mind that a raw file is not designed to be a viewable image (it has to be converted to another format first).

Each pixel on a bayer pattern sensor is only sensitive to one color (either red, green, or blue) because of filters being used over each photosite designed to filter out other colors. The value associated with each pixel is what is being stored in a raw file. Most modern cameras (with the exception of Sigma models using Foveon sensors) use a bayer pattern design:

http://en.wikipedia.org/wiki/Bayer_filter

A complex demosaic process is being performed by the raw converter to give it to you on screen in a converted format (so that you end up with red, green and blue values for each pixel location), and there are a number of different approaches to doing that. Here are a couple of papers describing some of the more common algorithms to try and "guess" the RGB values that should be used at a given pixel location (based on the values of adjacent pixels).

http://www.dalibor.cz/files/Ting%20C...erpolation.pdf

http://www.ece.gatech.edu/research/l.../bahadir05.pdf

Basically, a raw converter is going through this process when it loads a raw file. The original raw data from the sensor hasn't been modified (so, other programs can't understand what you did to it). To get to that point, you need to convert the raw file to a standard, viewable/editable image format that has values for red, green and blue stored at each pixel location (since you don't have all 3 colors represented at each pixel location in the raw file).

So, the raw converter is simply performing that demosaic process, allowing you to apply changes during the conversion (white balance, exposure, etc.). But, you'll need to save that converted image to a usable format like tiff or jpeg before you can edit it with an image editor.
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Old Sep 10, 2009, 5:55 PM   #12
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Faithful,
I've been using Adobe Camera Raw with Elements 7 and saving as a tiff file. Try going through a few others workflow for some hints. An example is:
http://digital-photography-school.co...-pros-approach
Google for others.
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Old Sep 12, 2009, 7:40 PM   #13
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Originally Posted by FaithfulPastor View Post
I guess I am still lost.
I have Photoshop Elements 7

I want to edit raw files, but I can't get PSE to do anything with RAW files other than convert them to jpeg or tiff.

What am i missing?
You aren't missing anything. PSE does not edit raw files. I can't offhand think of photo editing software that does. When you convert your raw files, some of the conversion programs allow a certain amount of editing prior to the conversion, but do not change the raw file itself. They store the changes in a separate database and apply them each time you open the raw file, leaving the original raw file as your 'digital negative'.

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Old Sep 13, 2009, 10:32 AM   #14
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Quote:
Originally Posted by VTphotog View Post
... When you convert your raw files, some of the conversion programs allow a certain amount of editing prior to the conversion, but do not change the raw file itself. They store the changes in a separate database and apply them each time you open the raw file, leaving the original raw file as your 'digital negative'.

brian
The Adobe Photoshop products do this also via Camera RAW. Photoshop CSn and PS/Elements can't open RAW files themselves. They rely on the Camera RAW plugin to do a conversion from RAW to a bitmap format that they use in memory (a very PSD like format). Camera RAW saves the adjustments, local and global, in a separate "sidecar" file when it is dealing with a camera specific proprietary RAW format (e.g. Canon's CR2, Nikon's NEF, ...). When dealing with Adobe's "standardized" RAW format, DNG, the data can embedded in the DNG file for easier file handling.

This saved data, effectively an Edit Decision List to use the old video editing term, is used as the default starting point the next time you open the RAW file and you are free to make further alterations before finishing the conversion. They are program specific. Other RAW converters can't read Camera RAW's sidecar files.

Some RAW converters, those that are made specifically for a particular proprietary RAW flavor, can save the edit instructions in the original file the way Camera RAW does with DNG. An example is Nikon's Capture NX2 which does this with their NEF RAW files.

Regardless of the way the conversion adjustment settings are saved, no actually editing is done to the actual image data in a RAW file. The original data is always present, unaltered.
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