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Raw Conversion Colourspace (ProPhoto?)

PostPosted: Thu Aug 04, 2005 5:01 pm
by NikonUser
I just got the book 'Real World Camera Raw' and have been flicking through it this afternoon.

It seems that it's suggested to use ProPhoto colourspace when converting RAW into photoshop. This is because ProPhoto has a much wider colour gammut than Adobe RGB.

Any thoughts/comments on this?

What colourspace to you guys convert to?

Thanks
Paul

PostPosted: Thu Aug 04, 2005 5:28 pm
by sirhc55
I only use Adobe RGB.

Found this interesting tidbit:

Even the best monitors struggle to display 98% of Adobe RGB. Unless the screen you are looking at cost in the region of $AU 7500 or more, then the odds are your monitor's gamut is only slightly larger than sRGb and about one third of the size of ProPhoto.

And why you should not use ProPhoto in 8bit:

Using ProPhoto with 8 bit files is digital imaging suicide! It is incredibly easy to introduce banding to a file in 8-bit ProPhoto. Nothing makes a digital image look crappy quicker than banding (except maybe the Unsharp Mask in most people's hands, but that will have to wait for another article!). ProPhoto is so large that having only 255 possible shades of each of Red, Blue and Green is a BIG PROBLEM! Quite simply the distance between tones is so vast you are almost guaranteed banding with only slight manipulations, especially if you try and recover detail in a slightly underexposed area of an image, i.e. the shadows.

And the argument with 16bit:

Converting from RAW into ProPhoto makes some sense, as you will likely not run into ANY significant clipping issues. Having said that, it is not actually common that your images will contain tones outside of AdobeRGB. It tends to be only image with extremely saturated colour (particularly yellows) that raise this problem. This is easily seen using the histogram in Adobe Camera Raw. Really, if your original capture does not contain tones out of the gamut of AdobeRGB, then there is no point whatsoever (and quite a few negatives) in using ProPhoto as your colour space unless you plan to artificially manipulate the saturation of your image to a considerable degree.


:) :) :)

PostPosted: Thu Aug 04, 2005 6:26 pm
by stubbsy
Wow Chris - stifled that debate quickly. Guess I need to revisit adobeRGB instead of sRGB (something which Mikhail prodded me about a while back, but I didn't get around to!)

PostPosted: Thu Aug 04, 2005 6:29 pm
by NikonUser
Wow that's quite an explanation! thanks.

I was thinking more about print than on-screen viewing though... but I read somewhere that printers can't even replicate Adobe RGB's gammut... Is that correct?

...And if I can't see it on screen then how will I know how it will look in print?

I think I'll stick to Adobe RGB.

Paul

PostPosted: Thu Aug 04, 2005 6:49 pm
by embi
I recently had an image printed at "The Edge" photographic lab in Melbourne. I picked up a leaflet that was very informative as to what colourspaces are best for printing. I thought about trying to copy the best bits here but havent got around to it.

Anyway Adobe 1998 is the best one for printing.

PostPosted: Thu Aug 04, 2005 9:18 pm
by Matt. K
Images should be captured in Adobe RGB if you intend to do any post processing. The colour gamut is wider then can be displayed on most monitors and it allows you to make some adjustments without the histogram turning into a comb. IE. The adjustments are fairly non destructive provided you don't overdo them. However, after PP then the images should be converted to Adobe sRGB as this is the colour space seen by your monitor, your printer and most printlabs, and you want to see what the image will look like before it is printed. This is ageneral rule and is also the method used by Thom Hogan. Hope this is useful.

PostPosted: Fri Aug 05, 2005 12:11 am
by sirhc55
Most colour printers will ask you to reprofile a ProPhoto to AdobeRGB :wink: