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  Previous versions of cgardner's message #11247707 « Raw for Dummies »

  

cgardner
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Re: Raw for Dummies


The biggest difference with respect to color correction is that RAW encodes the RGB sensor sites into pixels with color in blue/yellow and green/magenta channels, and the detail of the scene into a monochrome "luminance" channel that looks like a B&W image, not as RGB values as with JPG or TIFF. That makes it easy to adjust white balance with a tweek of the blue/yellow slider, or eliminate the greenish cast seen shooting under trees with a tweek of the green/magenta slider, or more importantly adjust contrast without shifting the color balance of the neutral tones by tweeking the contrast of the luminance channel.

Another advantage is bit depth. JPEGs are 8-bit (256 values) per color. In RAW you can use 16-bit (4048 values) per color which produces smoother gradients in areas like skies. WIth 8-bit JPEG corrections in curves or levels can cause posterization banding which won't with the same correction in the 16-bit file. A caveat when editing the RAW in 16-bit is you'll also want to use Adobe RGB or ProPhoto RGB as the editing color space in ACR, then convert to sRGB before converting to JPG at the end of workflow for screen images, a minor extra step vs. an all sRGB JPG workflow.

The "belt and suspenders" approach is to shoot in RAW+JPG. Try it for a few hundred shots, long enough to get the hang of RAW and edit a variety of images. Do what you normally to with the JPG for basic color / exposure / contrast correction. The do the same adjustments on the RAW copy in 16-bit mode, save as JPG, then compare with the camera generated JPG. You should find the more you need to correct capture flaws in exposure / color balance the better the result are with the RAW.




Feb 01, 2013 at 10:45 AM
cgardner
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Upload & Sell: Off
Re: Raw for Dummies


The biggest difference with respect to color correction is that RAW encodes the RGB sensor sites into pixels with color in blue/yellow and green/magenta channels, and the detail of the scene into a monochrome "luminance" channel that looks like a B&W image, not as RGB values as with JPG or TIFF. That makes it easy to adjust white balance with a tweek of the blue/yellow slider, or eliminate the greenish cast seen shooting under trees with a tweek of the green/magenta slider, or more importantly adjust contrast without shifting the color balance of the neutral tones.

Another advantage is bit depth. JPEGs are 8-bit (256 values) per color. In RAW you can use 16-bit (4048 values) per color which produces smoother gradients in areas like skies. WIth 8-bit JPEG corrections in curves or levels can cause posterization banding which won't with the same correction in the 16-bit file. A caveat when editing the RAW in 16-bit is you'll also want to use Adobe RGB or ProPhoto RGB as the editing color space in ACR, then convert to sRGB before converting to JPG at the end of workflow for screen images, a minor extra step vs. an all sRGB JPG workflow.

The "belt and suspenders" approach is to shoot in RAW+JPG. Try it for a few hundred shots, long enough to get the hang of RAW and edit a variety of images. Do what you normally to with the JPG for basic color / exposure / contrast correction. The do the same adjustments on the RAW copy in 16-bit mode, save as JPG, then compare with the camera generated JPG. You should find the more you need to correct capture flaws in exposure / color balance the better the result are with the RAW.




Feb 01, 2013 at 10:44 AM
cgardner
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Upload & Sell: Off
Re: Raw for Dummies


The biggest difference with respect to color correction is that RAW encodes the RGB sensor sites into pixels with color in blue/yellow and green/magenta channels, and the detail of the scene into a monochrome "luminance" channel that looks like a B&W image, not as RGB values as with JPG or TIFF. That makes it easy to adjust white balance with a tweek of the blue/yellow slider, or eliminate the greenish cast seen shooting under trees with a tweek of the green/magenta slider, or more importantly adjust contrast without shifting the color balance of the neutral tones.

Another advantage is bit depth. JPEGs are 8-bit (256 values) per color. In RAW you can use 16-bit (4048 values) per color which produces smoother gradients in areas like skies. WIth 8-bit JPEG corrections in curves or levels can cause posterization banding which won't with the same correction in the 16-bit file. A caveat when editing the RAW in 16-bit is you'll also want to use Adobe RGB or ProPhoto RGB as the editing color space in ACR, then convert to sRGB before converting to JPG at the end of workflow for screen images, a minor extra step vs. an all sRGB JPG workflow.

The "belt and suspenders" approach is to shoot in RAW+JPG. Try it for a few hundred shots, long enough to get the hang of RAW and edit a variety of images. Do what you normally to with the JPG for basic color / exposure / contrast correction. The do the same adjustments on the RAW copy in 16-bit mode, save as JPG, then compare with the camera generated JPG. You should find the more you need to correct capture flaws in exposure / color balance the better the result are with the RAW.




Feb 01, 2013 at 10:43 AM
cgardner
Offline
Upload & Sell: Off
Re: Raw for Dummies


The biggest difference with respect to color correction is that RAW encodes the RGB sensor sites into pixels with color in blue/yellow and green/magenta channels, not RGB as with JPG or TIFF. That makes it easy to adjust white balance with a tweek of the blue/yellow slider, or eliminate the greenish cast seen shooting under trees with a tweek of the green/magenta slider, or more importantly adjust contrast without shifting the color balance of the neutral tones.

Another advantage is bit depth. JPEGs are 8-bit (256 values) per color. In RAW you can use 16-bit (4048 values) per color which produces smoother gradients in areas like skies. WIth 8-bit JPEG corrections in curves or levels can cause posterization banding which won't with the same correction in the 16-bit file. A caveat when editing the RAW in 16-bit is you'll also want to use Adobe RGB or ProPhoto RGB as the editing color space in ACR, then convert to sRGB before converting to JPG at the end of workflow for screen images, a minor extra step vs. an all sRGB JPG workflow.

The "belt and suspenders" approach is to shoot in RAW+JPG. Try it for a few hundred shots, long enough to get the hang of RAW and edit a variety of images. Do what you normally to with the JPG for basic color / exposure / contrast correction. The do the same adjustments on the RAW copy in 16-bit mode, save as JPG, then compare with the camera generated JPG. You should find the more you need to correct capture flaws in exposure / color balance the better the result are with the RAW.




Feb 01, 2013 at 10:42 AM
cgardner
Offline
Upload & Sell: Off
Re: Raw for Dummies


The biggest difference with respect to color correction is that RAW records color in blue/yellow and green/magenta channels, not RGB. That makes it easy to adjust white balance with a tweek of the blue/yellow slider, or eliminate the greenish cast seen shooting under trees with a tweek of the green/magenta slider.

Another advantage is bit depth. JPEGs are 8-bit (256 values) per color. In RAW you can use 16-bit (4048 values) per color which produces smoother gradients in areas like skies. WIth 8-bit JPEG corrections in curves or levels can cause posterization banding which won't with the same correction in the 16-bit file. A caveat when editing the RAW in 16-bit is you'll also want to use Adobe RGB or ProPhoto RGB as the editing color space in ACR, then convert to sRGB before converting to JPG at the end of workflow for screen images, a minor extra step vs. an all sRGB JPG workflow.

The "belt and suspenders" approach is to shoot in RAW+JPG. Try it for a few hundred shots, long enough to get the hang of RAW and edit a variety of images. Do what you normally to with the JPG for basic color / exposure / contrast correction. The do the same adjustments on the RAW copy in 16-bit mode, save as JPG, then compare with the camera generated JPG. You should find the more you need to correct capture flaws in exposure / color balance the better the result are with the RAW.




Jan 07, 2013 at 01:14 AM



  Previous versions of cgardner's message #11247707 « Raw for Dummies »