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Author Topic: RGB or sRGB?  (Read 1528 times)

61Dynamic

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RGB or sRGB?
« on: January 04, 2005, 01:54:23 am »

The camera will either shoot Jpegs in sRGB or AdobeRGB selectable under the "Color Space" menu option. I'm sure that's what you mean as there is no other option that I'm aware of.

It would be recomendable to shoot AdobeRGB regardless if you shoot RAW or Jpeg.

Why for Jpeg: AdobeRGB is a larger color space which means it allows for a broader range of color. Very handy for editing and going to print. sRGB is "Standard" RGB and is the defacto RGB color space. It's fairly small. If you convert an image for printing from sRGB you will be much more likely to clip colors than you would with AdobeRGB.

Why for RAW: The camera shows you a preview of the image and a histogram after you shoot it. That preview is a small Jpeg and both the jpeg and histogram are made based off the parameters you set in the camera. By selecting AdobeRGB the histogram will show you a more accurate histogram as a RAW file can capture more color and luminotisy information than either jpg parameter can. If you set the camera ro sRGB, the histogram will show clipping sooner than it really is.

When you develop a RAW in PS CS, you can choose the color space the image will use regardless what it's set to in the camera. I'm not sure if you can choose a color space Elements 3...
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61Dynamic

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RGB or sRGB?
« Reply #1 on: January 10, 2005, 08:50:51 pm »

You can think of a color space (also known as a gamut) as a range of colors available in an image.

If you make an image in AdobeRGB (a large color space) it'll have a greater number of possable color values and you are less likely to see color cliping at the ends of the histogram.

8-bit/channel and 16-bit/channel is bit-depth and it effects color spaces in how many of those colors dictated by the color space can show up at any given time (simplified). Basically, if you use a color space that is too large for a 8-bit/channel image (like ProPhoto), it is possable to get posterizeation between colors after editing since the color values are more spread out and there just aren't enough bits of information to fill it in.

On my site I have examples of color spaces. The first is sRGB and the others are the two most common editing spaces AdobeRGB and ProPhoto. As you can see, the sizes are much larger than sRGB.

Edit in the largest color space possable (AdobeRGB for 8-bit/channel images and ProPhoto or similar for 16-bit/channel images)and save the image edits as a PSD or TIFF using the same color space. The only time you need to convert to a smaller color space (which thows away color data) is when you go to print or show stuff on the web.
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scubarob639

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RGB or sRGB?
« Reply #2 on: January 03, 2005, 09:55:29 pm »

I have a 20d and I have the option to use sRGB(default) or RGB. Does it matter which I use? And why?    I have P.S. elements 3.0 and not sure if I should shoot RAW mode or JPEG. Would this make a difference to the above question.

Thanks

Rob
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djgarcia

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RGB or sRGB?
« Reply #3 on: January 09, 2005, 11:24:39 am »

Can you please explain a "larger color space"? As I understand it, they're both either 8 or 16-bit spaces, same number of variations, the difference being in what the variations are in certain ranges of the spectrum. I could be wrong, though.

Having said that, I tend to shoot in Adobe RGB then convert and save after processing in sRGB. For some subjectively perceptual reason, I like the results from this.

DJ
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