sRGB vs RGB??

[scott1120]

Does someone have a link that explains these color spaces? I have never heard of PhotoPro RGB, is that something cameras can do or a PSCS2 thing? (I am trying to come up with real questions about stuff I do not know yet).

[johnastovall]

Originally Posted by scott1120

Does someone have a link that explains these color spaces? I have never heard of PhotoPro RGB, is that something cameras can do or a PSCS2 thing? (I am trying to come up with real questions about stuff I do not know yet).

Here is the best thing on ProPhoto RGB and why to use it.

It's not a PSCS2 thing but a color model thing. These color spaces are derived from the CIE color system.

[Wil_Bloodworth]

Originally Posted by johnastovall

Here is the best thing on ProPhoto RGB and why to use it.

<Caveat: I haven't read that article yet>

I must be missing something. If your camera body only supports the AdobeRGB color space then converting the RAW image data to the ProPhotoRGB color space doesn't introduce any new data. Right?! Only the 'bit buckets' where the AdobeRGB color space overlaps the ProPhoto color space will be filled-in. All the other ProPhoto bit buckets will be empty... thus leaving you with the same data that you had with AdobeRGB. Obviously, I'm missing something!

I'll go read the article now... and edumacate my ignorant self.

- Wil

[johnastovall]

Originally Posted by ParkImaging

<Caveat: I haven't read that article yet>

I must be missing something. If your camera body only supports the AdobeRGB color space then converting the RAW image data to the ProPhotoRGB color space doesn't introduce any new data. Right?! Only the 'bit buckets' where the AdobeRGB color space overlaps the ProPhoto color space will be filled-in. All the other ProPhoto bit buckets will be empty... thus leaving you with the same data that you had with AdobeRGB. Obviously, I'm missing something!

I'll go read the article now... and edumacate my ignorant self.

- Wil

AdobeRBG only applies to a converted in camera JPEG, not the raw data. Read the article.

Also get and read Real World Camera Raw with Adobe Photoshop CS2
by Bruce Fraser to understand what RAW is and isn't.

[Wil_Bloodworth]

Yes, I figured that out. There wasn't really mention of the rounding benefit of working in the larger color space. If you're doing a lot of CS2-type photo manipulations, it would be great to work in this color space so you can avoid all of the trucation through rounding.

For me, my monitor, printer, and photo labs do not support that color space. My customers are extremely happy with the current output that I provide (via AdobeRGB). I also notice that if you convert from the ProPhotoRGB color space down to AdobeRGB or to sRGB, the colors do not "pop" like they did if you started in that color space. That's kind of weird... I'll have to think about that one.

Interesting article though. Good read for sure! Thanks John!

- Wil

[johnastovall]

Originally Posted by ParkImaging

Yes, I figured that out. There wasn't really mention of the rounding benefit of working in the larger color space. If you're doing a lot of CS2-type photo manipulations, it would be great to work in this color space so you can avoid all of the trucation through rounding.

For me, my monitor, printer, and photo labs do not support that color space. My customers are extremely happy with the current output that I provide (via AdobeRGB). I also notice that if you convert from the ProPhotoRGB color space down to AdobeRGB or to sRGB, the colors do not "pop" like they did if you started in that color space. That's kind of weird... I'll have to think about that one.

Interesting article though. Good read for sure! Thanks John!

- Wil

You can still work in the color space and just convert before you do the final output. I print directly from ProPhoto to my R1800 and let the printer and profiles handle the conversion.

[Duffy Pratt]

The article John linked states the limitation of PhotoPro nicely: "What should be obvious is that if you work in the ProPhoto colour space you have no way of seeing what the colours that you actually have available are, and likely no way or reproducing them."

Rounding errors are likely to have more impact in a larger color space, not less. That is why its so important to be working with 16-bit images in PhotoPro RGB. In 8 bit, you start with 256 possible gradations per channel. In a wider color space, a jump between any two gradations is bigger. With 16 bits (actually 12 because thats what the cameras use), you start with over 4000 gradations, so the jumps between gradations are less, and the rounding errors are less significant.

Duffy

[Wil_Bloodworth]

Duffy: Re: Rounding... that's what I said... just in a different way.
John: Yes, but as I said before, working in the ProPhoto color space and then converting down to the target space makes the resulting image colors look washed out.

- Wil

[johnastovall]

Originally Posted by ParkImaging

Duffy: Re: Rounding... that's what I said... just in a different way.
John: Yes, but as I said before, working in the ProPhoto color space and then converting down to the target space makes the resulting image colors look washed out.

- Wil

I've not noted this wash out. And we are seeing more and more hight end printers which go beyond AdobeRGB.

[johnastovall]

Originally Posted by Duffy Pratt

The article John linked states the limitation of PhotoPro nicely: "What should be obvious is that if you work in the ProPhoto colour space you have no way of seeing what the colours that you actually have available are, and likely no way or reproducing them."

Rounding errors are likely to have more impact in a larger color space, not less. That is why its so important to be working with 16-bit images in PhotoPro RGB. In 8 bit, you start with 256 possible gradations per channel. In a wider color space, a jump between any two gradations is bigger. With 16 bits (actually 12 because thats what the cameras use), you start with over 4000 gradations, so the jumps between gradations are less, and the rounding errors are less significant.

Duffy

The new 14bit Canon raw images are going to be a very strong argument for large color spaces. As for not seeing some colors not visiable same as the square root of a minus one, it can help solve problems. Remember all color systems are an attempt to model a biological system into other modalities.

[Duffy Pratt]

Originally Posted by johnastovall

The new 14bit Canon raw images are going to be a very strong argument for large color spaces. As for not seeing some colors not visiable same as the square root of a minus one, it can help solve problems. Remember all color systems are an attempt to model a biological system into other modalities.

The only point that I'm making about not being able to see the colors is that it would take some hard proofing, coupled with some experience, to get a feel for what you are doing when editing in the out of gamut range. Whether the extra cost and effort is worth it is up to the individual.

The flip side is: If you have an image that fits wholly within sRGB to begin with, then you will be better off editing it in sRGB than PhotoPro, because you can do more subtle manipulations there. Ideally, you would use the smallest color space that is appropriate for the image and the intended output device. We don't live in an ideal world, and most people will pick a color space or two, and stick with them for editing purposes. As such, PhotoPro obviously gives some great results for some people. (And for some photographers, depending on subject, so does sRGB.)

Let me ask the question this way: suppose you are going to end up printing in B&W. Is it better to edit in PhotoPro or sRGB or some other color space?

Duffy

[AndrewCCM]

Originally Posted by ParkImaging

Duffy: Re: Rounding... that's what I said... just in a different way.
John: Yes, but as I said before, working in the ProPhoto color space and then converting down to the target space makes the resulting image colors look washed out.

- Wil

Are you "Converting" or "Assigning"?

I see absolutely no visible change in color when converting.

[billbunton]

Originally Posted by ParkImaging

Yes, but as I said before, working in the ProPhoto color space and then converting down to the target space makes the resulting image colors look washed out.
- Wil

It sounds like maybe you're assigning rather than converting. Going from a larger to smaller color space should, assuming you have nothing out of gamut for the smaller space, be visually the same.

[picasso]

Here is some very good information regarding color spaces in case you are interested. I ran across it last night. It almost has me convinced to purchase them. The reviews on the net are very good as well. Also, take a look at his gallery while you are there. He has some amazing images.

http://www.josephholmes.com/profiles.html

Paul