sRGB - AdobeRGB - ProPhoto RGB

Hello all,

 

Just so you know, I am using Lightroom 1.4 and PhotoShop CS3 Extended.

 

Looking through my preferences in Lightroom I noticed that when I set my

external editor to PhotoShop CS3 Extended, there is a little message next to

where you set the color space that changes depending on which color space you

select. If I select either sRGB or AdobeRGB I get a similar message, "The

AdobeRGB (1998) color space cannot encompass the full range of colors avaliable

within Lightroom...." If I select ProPhoto RGB I get a different message,

"16-bit ProPhoto RGB is the recommended choice for best preserving color detail

from Lightroom..."

 

Can someone tell me if which I should use, I thought I knew (AdobeRGB for

printing and sRGB for web) but now, what about ProPhoto RGB.

 

thanks

 

Layne

You want to stick with 16-bit ProPhoto RGB for as long as possible, switching to a smaller space only at the end when you need to (e.g., outputting a file for printing or web use).

 

In the LR/PS model, you'd stick with ProPhoto RGB through the round trip, and only change it when you export from Lightroom.

Pro Photo needs to be used as a 16 bit per channel color space. it is the largest of the availble RGB color spaces and encompasses pretty much the entire visible (to the healthy human eye) spectrum.

 

I use Pro Photo as my standard Photoshop color space.

They're progressively larger color spaces: ProPhoto RGB contains Adobe RGB and

more, Adobe RGB contains sRGB and more. As for usage i switched last year to

use ProPhoto RGB as long as the images are within my controlled environment,

Adobe RGB for files that go to clients who know what they're doing and do their own

CYMK conversion and sRGB for simple usages as email, web or the occasional

cheap machine print. If you're on a Mac check out the Color sync utility and select

the profiles, Hold to compare and marvel at the spaces (and compare custom color

profiles as well). It's a great tool to visualize what those profiles do and how they

compare.

best, m

This is not an answer, but more an extension of the original question. What is the value in adjusting an image in a color space with a larger gamut that the monitor in use? Assuming I am using a CRT with an approximate sRGB gamut, if I work in AdobeRGB or ProPhotoRGB, am I not creating or modifying colors that I cannot see on the monitor? Sounds like flying blind to me. (Maybe Andrew Rodney will see this thread and clarify this.)

"What is the value in adjusting an image in a color space with a larger gamut that the monitor in use?"

 

a good question but the reality is that you aren't flying blind. The behind the scenes software (the color management module or CMM) does a very good job of emulating larger color spaces on a smaller gamut display device . Not perfect of course but far better than you fear. The better the display of course the better the results.

Thanks, Ellis. I was thinking perhaps something akin to perceptual rendering intent might do this, compressing the gamut for display purposes so that relative differences in colors might be evident.

Everyone also needs to keep in mind that using Prophoto can lead to banding, if you do large editing changes in post.

 

If you use ACR, you can switch between all three spaces, and watch for clipping in the histogram, to see if you NEED to go to a larger space.

"Everyone also needs to keep in mind that using Prophoto can lead to banding, if you do large editing changes in post. "

 

Prove it. I've been using Pro Photo (in 16 bit per channel form) for over four years and have never seen that happen.

If you're on a PC using XP (I figure it'll work in Vista too, but don't know as I'm running XP) you can download wincolor.exe from Microsoft for free. It's another program that lets you compare color spaces visually. It's great.

 

I don't have the link, but I found it (after reading about it) with a google search. As far as I know, it's not bundled with the operating system.

 

Incidentally, I've also been using ProPhoto for a while now and have never seen banding.

After reading an article by Andrew Rodney which he posted in another thread I switch to ProPhoto. It eliminated much of the high end clipping I was picking up in ACR with sRGB. This leads to better control and range of exposure in ACR and I think more accurate printes. The article really opened my eyes about color space and the management thereof. Sorry I can't remember which thread it was but it was within the last couple of months.

A quick google search does show reported banding problems with Prophoto in 8 bit. I've never noticed it but usually always in 16 bit.

<i>"You want to stick with 16-bit ProPhoto RGB for as long as possible, switching to a smaller space only at the end when you need to (e.g., outputting a file for printing or web use)."</i>

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This is the what I learned when I first learned about colorspaces, and as a result, have my default set to ProPhoto.

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However, lately I've begun to question the wisdom of that. Basically, I could see the wisdom of <i>capturing</i> in ProPhoto, or some other super-wide gamut if you have the capability to do so ﾖ this will give you a "digital negative" that you can use to make images when future monitor and printing technologies that aren't around today (actually, this is what Camera Raw is for, really). However, for printing or web publishing in the here and now, ProPhoto is a way bigger color space then one could possibly use ﾖ to the best of my knowledge, even really good printers are only capable of rendering in Adobe RGB as their widest gamut. (Correct me if I'm wrong on this.)

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The downside as I see it of working with ProPhoto is that you're inevitably going to have to downsample at some point. If you do so at the very end, there's a high likelihood that in you have all kinds of out-of-gamut colors. In fact, you might have even increased the number as you worked on the image color in ProPhoto. Neither the Colorimetric or Perceptual rendering intents that exist now to downsample to a smaller color space are perfect, and may have very real problems if a lot of your color is out of gamut, resulting in banding or like artifacts. On the other hand, if you start with or switch to the color space you're going to output in early in your workflow, you will only be shifting colors within the bounds of what you can actually print. Now, I'm not sure if having a wider gamut gives you some advantage with color correcting or otherwise rendering color even knowing you're going to downsample later.

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Thoughts?

Hello again,

 

<br>My portfolio can be seen here - <a href="http://www.photo.net/photos/LVX">http://www.photo.net/photos/LVX</a>. <br>Please notice that one of the images is slightly red. The rest look OK as far as the color is concerned. Any ideas as to why. I use Spyder to calibrate my monitor and the red image (I will not say which one is the red one - please tell me so I know if you see it as well) looks fine at home but red when I look at it on other monitors.

 

<br>any advice?

 

<br>Layne

"A quick google search does show reported banding problems with Prophoto in 8 bit."

 

Pro Photo is definitely not meant to be used as an 8 bit color space as it is way too large.