Color Spaces Etc.
We received a question via email from a Paper Arts community member. With permission, I am publishing that question along with an answer in todays newsletter. This question or related questions come up constantly in our workshops. I hope this helps other members. Please comment, question, or ask for clarifications in the comments.
Hello, This question came up after having an issue with my color lab not printing my image correctly. I shoot in the camera in RAW with the camera profile set to ProPhotoRGB. That gives me as much latitude in color capture as is available. I import images into Bridge and process them. When I saved I saved it in ProPhotoRGB. The photo lab that does my work said they cannot support ProPhotoRGB as it is too wide of a gamut and the colors fall outside of the range of the printer. The lab supports sRBG or Adobe RGB as they have a narrow gamut. I switched my preferences in RAW to AdobeRGB 1998 and use the labs ICC profile for soft proofing. My question is this and there might not be a simple answer. Why do we even have ProPhotoRGB if the labs cannot use it?
Christopher Boles Prescott Valley, AZ
Service Providers
First up, when sending files to any service provider do whatever they say. Send the file type, color space, and profile they ask for. Don’t ask me why but most print providers seem to be hopelessly rigid and appear to be completely unable to comprehend anything but what they ask for. Then again they may have had a lot of confused customers that demanded a refund due to absolute incompetence on the customer-end which prompted the draconian policies.
When in doubt as of the 21st century, send sRGB. Why? Simple most monitors will show you sRGB or at least the same shaped color space as sRGB. Most customers evaluate color using a monitor. To this day I cannot possibly understand why service providers insist on dumbing down color spaces that do not take advantage of the capabilities of their own hardware. It’s one of those mysteries of the universe… or it’s as I’ve speculated above where delivering a print that shows something not seen on a customer’s monitor is bad business.
What do I mean by sRGB shaped color spaces?? I implore you to take a look at the fine art printing eBookif you’ve not already. Specifically, take a look at the section on color management. It’s long and complicated but I explain a lot more there. The following might help the eBook color management section a bit easier to digest.
Camera Settings & RAW Software
When shooting RAW in your camera the color profile settings don’t have anything to do with the output of your RAW file. They don’t influence anything to do with your post processing or it’s output. The most they do (depending on the camera) is that they might influence what color profile the embedded JPEG happens to be within the RAW file which most software ignores.
RAW processing software, including Camera RAW and Lightroom use a super wide gamut space internally (probably ProPhotoRGB or wider). Any settings available such as AdobeRGB in your case influence the output not the internal working space. Taking Camera RAW for instance when you set it to AdobeRGB the process goes more or less as follows:
The camera RAW file is decoded from its own color space and profile into the internal wide gamut working space.
The adjustments are performed on the image in that wide gamut space.
The results of the adjustments are translated and output into whatever color space you’ve set such as AdobeRGB.
Taking the example farther with Camera RAW, you can clearly see that the color profile setting applies to that output even in Photoshop. Assuming your photoshop is using the default color settings, when it’s finally opened in Photoshop the profile inside photoshop will be Adobe RGB if that what is set in your Camera RAW settings. The same will be true if you set the Camera RAW output settings to ProphotoRGB, sRGB, or any other profile. The working space of Photoshop will be whatever was set in Camera RAW.
Lightroom works the same way, at least in the develop module. If you are working on a RAW file the internal color space in the develop module will be a wide gamut space, far far wider than any real-world output device be it monitor or printer.
Why ProphotoRGB & The Ugly Truth
We finally get to your question; Why ProfotoRGB? The better question is why any super-wide gamut color space that is far beyond what can be reproduced on any actual device?
The answer is analogous to why use a large bit depth when processing files or even why not just 8bits when capturing an image? The simple answer is that you maintain as much tonal and color information through the entire image pipeline from capture to output as possible without throwing any out along the way. Shooting RAW and using any modern RAW processor accomplishes just that. Any reduction in color or tonal information is done at the output stage.
Let’s think about sRGB vs AdobeRGB for a moment. What is so good about AdobeRGB vs sRGB? Everyone knows it’s ”bigger”. Where’s it bigger? It’s bigger in areas that ink on paper can reproduce but sRGB monitors cannot reproduce. In other words if you have an AdobeRGB monitor you can see more of what paper and ink can do than what sRGB monitors can do. Can you see all of what paper and ink can do? Nope. What about P3 color spaces (modern Apple monitors etc.). That color space is about as big as AdobeRGB but shifted away from what papers can do and towards what high gamut monitors and projection devices can do. Great for filmmakers.
Hmmmm, AdobeRGB, sRGB, and P3 do not contain everything that paper and ink of modern pigment printers can do. ProphotoRGB and other super-wide gamut spaces do contain what ink on paper can do. By using these super-wide gamut profiles and carrying them all the way through to print you will not throw color away before they are ultimately translated to the paper/printer profile and printed.
I’ll spell out the ugly part of this. All monitors including sRGB monitors can display colors that paper and ink just will not do but you can see clearly when evaluating images on your monitor. When soft-proofing the only thing that’s going on is that those super-bright, super-saturated colors that monitors can do are being dumbed down to what the paper/printer profile you are proofing to can do. Obviously soft-proofing cannot make your monitor do things that the paper/printer combination might be able to do.
Why’s this the ugly truth? Because most of the problem people have is with super-bright super-saturated colors (like pinks and reds) that even sRGB monitors do very well that no paper/printer can do at all.
I hope this shed some light on your question, let me know. If it just confused you or anyone else more, definitely chime in and I’ll attempt to explain in a way that’s more clear. Things like this are why Les & I host things like our hands-on Intro To Fine Art Printing workshops. For those that cannot attend I’ll do my best to explain or help where I can.
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One important thing to understand is that there are input profiles, profile connection spaces, and output profiles. Camera raw files are in an input space, not ProPhotoRGB, Adobe98, or sRGB. Printer output files are in an output space, based on the capabilities of the inks, paper, and marking engine, plus choices made by the profiling method and settings.
So, ProPhotoRGB is a connection space. A robust workflow will support this space as input to connect to a printer profile, but opening color space up to whatever the photographer wants is not favored by most printers, because of the reasons called out in the article, plus fun bonuses like corrupt or stunt profiles used by some pro photographers as reasons to print only through their workflow.
The other thing important to consider is bit depth. Raw files are nearly always in higher bit depths (12, 14, or 16 bit, usually), so converting to 8 bits while maintaining a very wide gamut will quantize the colors *more* than converting to 8 bit sRGB.
In short, “do what the printer asks you to do” is sound advice. Camera raw and high-bit-depth ProPhotoRGB gives you the widest gamut and possibilities on the front end, but consider the trade offs being made to display these files onscreen, and on to print.
There were several opportunities which were lost in the conversation namely,
1) A calibrated workflow is a necessity if one wants a reasonable expectation of achieving consistent and predictable results,
2) Most users need to turn down their monitors’ luminance to around 80 Cd/m2 if their final destination is printing.
3) Room ambient light and illumination sources are important considerations when post processing for print.
4) While there are numerous advantages to editing in a larger color space such as ProPhoto, primarily lack of rounding or mapping errors, these advantages do not necessarily translate into better or more desirable prints. Commonly employed monitors can at most display sRGB or 99% of aRGB. Thus, one cannot visualize on conventional monitors what might be lurking in the file or how it will appear on the output. A great example occurs when printing portraits and if one exports the results in aRGB to a company whose printers are operating in the sRGB color space, the skin tones will likely appear orange/yellow in the output. In this scenario, the user is wiser to convert the print to sRGBand deliver the final proofed print as intended.
There are many other interesting points to discuss, though as you indicated, they are better covered in a course on printing. Cheers!