RAW - aRGB vs sRGB

jchin

I was told today that even though I shoot RAW (no JPG), I still need to to use aRGB and then convert to sRGB JPGs before I get them printed online; being that aRGB will give me a better color space to work from and thus better color prints. Is that true? :huh

My Canon 20D and 40D are set to capture RAW and use sRGB (if that matters). When I get home, I convert the RAW using DPP to JPG for online prints (Smugmug or dotPhoto). Would having aRGB be any better? Or was I told a bunch of hog wash?

Thanks.

jfriend

It sounds like hogwash to me. When shooting RAW, it does not matter what the colorspace in your camera is set to. It does not affect the bits of the RAW image at all.

I shoot RAW, adjust images in Lightroom and then I either print directly from Lightroom or I export as sRGB images for the web. It does not matter what colorspace my camera is set to.

jchin

Thank you. I thought I was losing it.

arodney

Raw is Raw, the setting has NO effect on that Raw data. It does on the preview on your LCD (clipping etc). But since you're not shooting JPEG, the preview there isn't at all a reliable indicator of the actual data.

It does affect the tiny embedded JPEG in the Raw which will be ignored and overwritten by the Raw converter anyway.

al'be:do

RAW data are normally stored in a wider gamut color space that is dependent on the camera. This internal camera color space is well specified and also all corrections made in this space can be a lot more precise than working with a photo that's converted to AdobeRGB or sRGB.
If you want to process the photos for the later use on monitor displays or for printing then using a wider color space can be better, depending on the target device.
AdobeRGB is a bit wider than sRGB, especially in the green color range.
Normally the Photoshop color management system (or whatever program you use) should take care of any color space transformations that are necessary, if you configure the program appropriately.

sesshin

The only time you need to worry about a color space is when you leave your raw program. For instance if you are editing in Photoshop I would export out of DPP in the widest color space and resolution (Pro Photo / 16-bit / TIFF) and do all the editing using that. THEN convert to sRGB if the image is going on the web. This ensures all your editing was done with the least amount of destructiveness.

If you just going straight from DPP to web image though you only need to convert to sRGB jpeg once and be done with it.

Tee Why

If you are shooting RAW, color spaces do not apply. It's when you convert the RAW images to JPEG for printing online, that you have to pick a color space. Most online printers use sRGB. I think your monitor and online viewing of images are set to sRGB as well. So it may give you more consistent colors to go from RAW to sRGB JPEG images and print in that color gamut as well.

AdobeRGB is a little bit wider, but I think for most of the time, the difference, if any, will be small and not worth the hassel of managing through two different color gamuts.

Good luck.

arodney

Tee Why wrote:

Most online printers use sRGB.

No, most online printers ask for (some require) sRGB. None of those printers output sRGB, that's impossible (its a display color space). And the output of nearly every such printer I've profiled have gamuts that exceed sRGB in some useful colors. These labs are lazy and don't implement color management to its fullest (I'm being kind). They want to pump through large numbers of documents without having to worry about proper color space conversions to their printers native output space so they setup queues that assume everything is in sRGB and then convert to the native space (which isn't anything like sRGB).

For the time being, ignoring such sloppiness in terms of the original color possibilities, the only real use of sRGB is for web (or slideshow/projection). And even that's starting to go as more displays provide gamuts that exceed sRGB and match or exceed Adobe RGB (1998).

jaswebpics

So, for the moment, what do you recommend Andrew? Work with the file as AdobeRGB(1998), giving you the biggest range of tones to manipulate, then as a final step, convert to what the provider wants, in this case sRGB?

arodney

jaswebpics wrote:

So, for the moment, what do you recommend Andrew? Work with the file as AdobeRGB(1998), giving you the biggest range of tones to manipulate, then as a final step, convert to what the provider wants, in this case sRGB?

16-bit ProPhoto RGB is what I recommend for master images. Considering that my Raw converters (ACR and Lightroom) use that as their processing color space (just the primaries, the TRC gamma is linear), I see little reason to use anything smaller. Plus my output devices (K3 and HDR Epson inks) exceed Adobe RGB gamut in a lot of colors. Not so with Prophoto RGB. One can always convert an iteration of that master into sRGB for web use.

http://www.adobe.com/digitalimag/pdfs/phscs2ip_colspace.pdf