sRGB VS RGB
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Old 09-12-2006   #1
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Default sRGB VS RGB

quick shots from last nite

RGB (what ive been shooting in)


sRGB


i think the latter looks more saturated??

phats

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Old 09-12-2006   #2
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Default Re: sRGB VS RGB

I don't have time to go into it right now, but it appears that you are assigning profiles to images, rather than converting. NEVER assign! ALWAYS convert! Seriously, I'll come back to this post later this evening, and explain further.
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Old 09-12-2006   #3
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Default Re: sRGB VS RGB

For the web, convert your files to sRGB. Adobe RGB is a wider gamut color space and good for editing and even print but will look flat when displayed on the web or in a program that is not color space aware.
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Old 09-13-2006   #4
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Default Re: sRGB VS RGB

OK. You have three basic areas of the workflow: capture space, working space, and destination space. If you are using raw format, capture space won't be relevant, since you can just assign you working space in the raw converter.

If you're in jpg mode, then the default is sRGB. sRGB is a web friendly color space designed for monitor displays. It's got a good range of colors, and since most uncalibrated monitors are targeting that output, your pictures will display somewhat close to the way you intend. By somewhat close, I mean blue will be blue, red will be red, but the contrast (white point) and brightness (black point) might be off a bit. Chances are, the uncalibrated monitor will look a little cooler in color cast due to a slightly high target temp. like 9300 K. But it's close enough.

Back to the camera capture mode. Some cameras have the option of using a wider colorspace, Adobe RGB. This has a wider gamut than sRGB, meaning all the colors available in sRGB are contained in the Adobe RGB colorspace. All that, and then some - particularly in the saturated reds and blues. If you want to get into this advanced color management, I suggest you invest in a monitor calibration software/hardware bundle. B&H has a pile of them. Look for something in the $200-300 range and make sure it uses measured luminance. Remember that variable contrast and brightness I mentioned - this'll fix that on your monitor.

Short of calibrating your monitor, if you have Photoshop, you can use Adobe Gamma to get your monitor in the ballpark. Go to the Control Panel to run the wizard, and follow the instructions.

OK, you have a calibrated monitor and you're still wondering what capture workspace to set your camera at. If you are going to do anything more than crop and resize your images - tasks like color correct, sharpen, tone, touch-up, reduce noise come to mind - then I recommend using a wide gamut workspace. Adobe RGB, or aRGB for short fits that bill. If you are using raw format, there are even larger gamut color spaces, but save those for when you are more comfortable with color management.

While we're on the topic of raw, jpg and color, let's address color depth. If you are going to shoot in raw, make sure your output color depth is set to 16 bits per channel and save as a psd file. This will ensure that you extract every bit of color data from that raw file. If you are shooting in jpg mode, and using Adobe RGB, you will want to convert to 16 bits per channel by using Image > Mode > 16 bits/Channel. This will allow extremely sensitive editing, and reduce posturization in the final output. It's also a good idea to File > Save As... and choose psd. Consider this psd (either from raw converter or the jpg) you digital negative. Forget what everyone else says about raw being a "neg" - the analogy doesn't really work. You can edit this and retain the final version for cropping, reprints, different sizes for websites, etc. later.

If all you are going to is crop and resize, then choose sRGB. It'll save you the step of converting to the destination space. This called early binding to the destination space. It is absolutely fail safe. You can't get your colors messed up.

So at this point, you've decided these are wedding pics, and you want the most color possible for your pics. Well not so fast, most print services require files be sent converted to sRGB. So, in the end, you aren't gaining any overall color, but while you editing, you have a much larger pallet of color to work with, and that larger pallet will result in smoother edits.

After you are done editing and you are ready to switch to your destination space, or sRGB, go to Edit > Convert to Profile... and choose sRGB as the convert to space. Then you can (and this is the same for the raw workflow, or jpg workflow) use Image > Mode > 8 bits/channel to reduce the bit depth, and File Save As... a jpg. Use Quality 12 for this step.

So, either set the camera to sRGB and forget it. Or, take advantage of the wide gamut colorspaces available.

Review:

For jpg workflow:
Set camera to Adobe RGB
Set Photoshop working color space to Adobe RGB
Convert jpgs to 16 bpc
Edit
Save as a psd
Convert to sRGB
Convert to 8 bpc
Save as jpg.

For raw:
Set converter to 16 bpc, aRGB
Edit
Save as psd
Convert to sRGB
Convert to 8bpc
Save as jpg

For simple sRGB (Early Binding)
Set camera or raw converter to sRGB
Edit - make sure you convert to 16 bpc
Convert to 8 bpc
Save as jpg
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Old 09-13-2006   #5
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Default Re: sRGB VS RGB

Thank you very much for the excellent explanation!
I have just one more question:
Which profile do you recommend to use for calibrating the monitor, sRGB (to see how the photo looks on the client's monitor, or in print) or aRGB (for editing in this color space)?

Best regards,
Klaus
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Old 09-13-2006   #6
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Default Re: sRGB VS RGB

When you calibrate the monitor, you'll be creating a custom profile for that monitor. The software should automatically apply it to the video output settings. That custom monitor profile will describe how the monitor will display the colors. The colorspace used in your image file describes the colors used. Make sense? So, you'll set your driver up to the default (for Windows its already sRGB) and the run your calibration tool, and create a profile that modifies the driver output. The tool should apply this to the video output itself. I use a Spyder2 Pro kit, and it uses a program called Profile Loader.
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Old 09-14-2006   #7
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Default Re: sRGB VS RGB

Thank you very much for enlightening me! I finally got it. The whole picture ... not so complicated after all!

Best regards,
Klaus
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Old 12-23-2006   #8
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Default Re: sRGB VS RGB

Quote:
Originally Posted by CogSci
Thank you very much for enlightening me! I finally got it. The whole picture ... not so complicated after all!
I second that Thankyou very much jfrancho.
Jay
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Old 12-23-2006   #9
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Default Re: sRGB VS RGB

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Old 01-01-2007   #10
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Default Re: sRGB VS RGB

jfrancho

Excellent explanation

I have to question: "you will want to convert to 16 bits per channel by using Image > Mode > 16 bits/Channel. "

If you start with a 8 bit file ( jpg) and are just doing minor tweaks ( levels?) what real value is there in going to 16 bit?

It makes sense to me if you are shooting raw ( 12 bit) and working in 16 bit mode ( my preferred workflow)

Your thoughts?

Glenn


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