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I am fairly new to photography, and I have heard many people say that I should import my images in Photoshop using ProPhoto RGB as color space (only for the RAW images).

However, when I import my photos using 16-bit ProPhoto RGB, Photoshop tells me that "The document... has an embedded color profile that does not match the current RGB working space".

It gives me three options: to use the color space I wanted, to convert the color profile to sRGB (as my monitor, I guess) and lastly to not use a color profile and thus not handling color at all...

I have tried before to check the "keep using ProPhoto RGB" box, however when I exported my picture as JPEG and watch it on my phone, or also when trying to post it on Instagram, the colors suddenly became unsaturated and ugly, very different from the colors I saw on my PC screen.

Also, another question that I have is: if my monitor can only display sRGB color space, why would I use ProPhoto RGB? If my idea is NOT to print a photo, but mainly web usage, is it really necessary to retain colors that my screen cannot display? Also, if my monitor cannot display those colors, how do I know that I am not "messing them up" (what if for example I mistakenly change the luminance or hue of some colors that I cannot see because they cannot be displayed? How would I even know that I did a mistake?).

I hope my question is clear, although it probably isn't, as my noobish nature makes me not really understanding color spaces at all...

Thank you for your patience!

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Let me first say that everything that's happening is exactly how it should be. Even the fact that Photoshop gives you a warning, which is a matter of its Color Settings (see below). And your concerns are absolutely valid.

In a TL;DR fashion, I'll say this: only use a non-sRGB profile if:

  • You have a colour-calibrated monitor (and, in fact, the whole workflow);
  • You have a wide-gamut monitor;
  • You are prepared for the inconvenience of handling the correct colour-managed workflow (both mentally and practically).

Otherwise, stay with sRGB. Even if you do observe colour management (which is always good), it will make your life much easier, especially for your intended purpose (i.e. web/sharing photos with others).

Now the rationale.

It is true that the RAW photos of any decent camera can store more colours than what fits in sRGB (and what most monitors can display). It may feel that it would be a waste to clip them. Sure it is. But what can you do? Your output device (and that of 99% of people) is fundamentally incapable of displaying them. If you think that at least those 1% (or your printing lab) will see them, ask yourself: how are you going to process your RAWs into JPEGs and ensure that the colours that you don't see are good? [1]

If you are worried about preserving the data for posterity, you should keep your RAW originals and the XMP files (or whatever files your RAW processing software writes) that record your processing settings. If you buy a wide-gamut monitor later and want to enhance your photos, you can then load your mostly-processed RAW again, switch to AdobeRGB (or something even wider) and enhance them further.

Handling correct colour management is another skill or, I should say, a mindset. Always remember that it is only as good as its weakest link. If you do apply it, you must apply it at every stage, from display settings/calibration to photo processing to photo viewing, otherwise it all loses sense. This latter, viewing, is often the weakest link: the processing environment is at least in your hands, but viewing is in the hands of the people you share your photos with. Given that the same 99% are oblivious to colour management, you can safely assume that the colour profile you carefully attached to your photo will be ignored in most cases. This is exactly why your ProPhoto images look so washed out for other people.[2]

I like this analogy: using colour management is like specifying and handling physical units to measurements. Engineers (unlike typical IT people) know their importance and how to handle them. They know that numbers by themselves are simply meaningless. But once you know (or declare) that "3" is actually "3 metres", you can work with it. You can convert it to feet, scale it, etc., all with full knowledge of what's happening. But if you lose the unit at any stage of the process, you no longer know what it is, and all is in vain.

Same with colours: Red=3 in sRGB is physically a very different thing to Red=3 in ProPhoto. The colour profile attached to the photo specifies these units. Ignore it at your peril. Yet your users will likely ignore it. This sadly applies even to many printing labs.

So, not only you should measure your monitor (ideally with a colorimeter), but you need to ensure that:

  • Your operating system records this measurement (in the ICC or another profile);
  • Your processing and viewing software uses this profile (some software ignore the OS profile and rely on their own custom settings);
  • The software processes conversions correctly (has a good management engine). Converting colour profiles is much less trivial than converting metres to feet, and even requires user input (so called rendering intent).
  • The actual colour profile is attached to every photo you produce.

What if a photo doesn't have an attached profile? For an engineer, not specifying units is a crime, unless the default unit is strictly stipulated. Unfortunately, for missing colour profiles there are two equally common assumptions: 1) assume sRGB (preferred; all professional software have a settings which profile to use in this case); 2) ignore colour management, i.e. directly map the photo gamut to the monitor gamut. However, given that most monitors (excluding laptops) are not too far from sRGB, the results are similar for most people.

Given the sad fact that most people will ignore the profile and fall back to one of the above scenarios, your workflow should include an additional annoying step if you decide to use a non-sRGB workspace:

  • Prior to sharing the photo with anyone (and, in most cases, for printing it in a lab), convert it to sRGB and share that converted one.

I have a wide-gamut monitor and use AdobeRGB as the working colour space. But I'm also an engineer as you could guess and I naturally keep all these things in mind without trouble. Yet for many people, adherence to strict non-sRGB colour management is difficult enough to poison their lives (more mentally difficult rather than actually difficult). Yet again, if you don't do it strictly, you'd better don't do it at all. Missing one step will simply produce unpredictable result, quite possibly worse than if you didn't do anything special.

By the way, those Photoshop colour settings... To have a clear mental picture of what's happening, you should tell Photoshop to alert you of any profile mismatch:

Photoshop important color settings

And if you have a non-sRGB image or monitor, you don't have an option to ignore mistmatches and colour management in general. It would be like pasting an imperial piece to a metric drawing and pretending that it's OK to consider "3 inches" as "3 mm".

As for ProPhoto specifically... This is a very wide all-encompassing profile which is alsmost guaranteed to be wider than both the monitor and the camera. But apart from the same problem of editing it on a standard-gamut equipment where you don't see all these extra bits, you have a new one: it's so wide that the 8-bit resolution is not sufficient for it. (You are stretching the same 256 steps over a much greater breadth of the gamut, and even untrained eyes can see these steps). So you need to move to 16 bit. But as we know, JPEG doesn't support 16 bit, so you'll be limited to more exotic or lossless formats.


[1] This is not impossible: histogram is your frend. But editing "by numbers" is a special skill, and you still need to "calibrate yourself" on a real device.

[2] In the most typical situation, photos made for a wider gamut will always look desaturated and flat on normal (sRGB) displays. The reverse (oversaturation) happens if you have a wide-gamut monitor and view other people's sRGB photos while ignoring colour management.

  • Good answer overall but note that a camera RAW file can certainly capture a pure 500nm, emerald green from a laser or through a narrow filter. However, it is also well outside ProPhoto RGB and so will be clipped and desaturated when rendered in ProPhoto RGB. – doug Dec 20 '18 at 2:55
  • Surely it will capture; the question is: will it distinguish it from the closest ProPhoto green? Only then can we say that it matters. That said, some cameras capture near-infrared. There are always special cases. That's why I said "almost" :) – Zeus Dec 20 '18 at 3:23
  • It could easily distinguish such a color but only if it could render it in a larger colorspace than ProPhoto RGB. Even if a camera had "perfect" CFAs that met Luther/Ives it can't distinguish the color from one on the ProPhoto RGB limits absent converting to a colorspace larger than ProPhoto RGB. Even though such a camera would be able to capture the entire visible gamut. It's the target colorspace that limits the rendered image. ProPhoto RGB remains an excellent choice because reflected colors from real life objects are almost always inside ProPhoto RGB. – doug Dec 20 '18 at 3:31
  • Zeus: Excellent comprehensive article. @doug Technically, camera RAW doesn't distinguish anything, the deBayering algorithm does. The Bayer filter would certainly allow 500nm to be recorded, but a camera is just a tristimulus recorder, (and generally not Luther for various practical reasons.) There are larger spaces such as ACES which encloses 100% of the CIEXYZ diagram, but they aren't useful as a practical matter. Mainly, you want a working space that is not going to clip during your workflow or output. The actual "best" way to do that is to work in linear floating point (32 bpc). – Myndex May 6 at 6:52
  • The problems I have with ProPhoto are: 1) it uses imaginary primaries not within the locus, 2) it uses D50 which is a non-starter if you are working in D65 or D63 and need an unbounded space, and 3) it's substantially larger than needed for practical purposes. As a practical matter, you simply need to "not clip," and if you aren't clipping in the space you're using you gain no benefit from a larger space, but you do get larger delta-E erors that you don't want! – Myndex May 6 at 6:54
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It depends on your intended purpose. If your output will be on typical screens (monitors, phones etc) then sRGB is going to get you the best most consistent colour accuracy. ProPhoto RGB has a wider colour gamut and so is technically better but you would only see the benefits if you are outputting to a medium that uses that colour range such as high quality print. You monitor won't even display that colour range and so you won't accurately be able to check colours.

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I have an Epson printer / and print paper combination that gets very close to Pro-Photo RGB color gamut so for this printers workflow I use Pro-Photo. So the answer is that if you have a reason as I do to use this colorspace then ProPhoto is the best tool for that workflow.

Here's an example: sRGB and Epson S900 printer gamut comparison

To the assumption below that "no printer can print all colors in sRGB" while this may be true it has no bearing on why a color space profile is chosen for any specific workflow. The real reason to chose ProPhoto over sRGB or Adobe 1998 is simply gamut volume. If the gamut volume of the printer is larger than the container space, Gamut mapping cannot happen. So the container space must be larger than the destination space.

For this printer, ProPhoto is the only color space profile that will contain the full gamut volume.

If the workflow is meant for commercial print then sRGB is too small because cyan colors are clipped in this gamut and the print space is larger.

  • The colorspace printers have is quite different than RGB colorspaces. However, all printable colors can be contained in ProPhoto RGB which is why it's best for printing. But ProPhoto RGB also has a lot of "colors" that not only can't be printed, many are imaginary colors. For that matter, as small as the sRGB colorspace is, no printer can print all colors in sRGB. Printer colorspaces and RGB colorspaces have radically different shapes. – doug Dec 20 '18 at 2:47
  • That would be correct except for the whole process of ICC profile transforms. You see that's where the math comes in to transform one gamut to another. So if you use ProPhoto colorspace and have printer close to SRGB the transform is huge and inaccurate. Much better to choose the correct and closest container space for your destination workflow. – R Hall Dec 20 '18 at 13:51
  • There is, unfortunately, a widely held, and commonly stated, view in many articles on the net, that printed image colors depend on the gamut the image is encoded in. This is not the case outside of highly specialized processes like device link ICC profiles. These are not used by photographic printing from an RGB space. A printable color in ProPhoto RGB will print exactly the same as the same in sRGB. This is because a color in an RGB space is first converted colorimetrically to the ICC PCS. From there it's converted to the printer's space. That conversion has no idea what the RGB space was. – doug Dec 20 '18 at 15:43
  • Doug, If the color is "Printable" it will be inside the gamut of the printer. As the plot above clearly shows there are colors in the gamut of the printer that are not available in sRGB, so your statement may be true for a subset of colors but impossible in the case shown above. The rest of the world does use ICC profiles to characterize printing devices and yes they do provide excellent results, but not all results for each profile gamut volume The RGB space is known in any ICC conversion because the values are mapped to CIELab. – R Hall Dec 20 '18 at 15:57
  • 1
    Then we are in agreement. BTW, I don't know why you were down voted. I agree one should use the largest RGB space that encompasses the colors in any given image. But one should be careful with ProPhoto RGB. It has the most unprintable colors of any colorspace and so editing an such an image should be done with care. My initial response was just pointing this out. That ProPhoto RGB has a huge number of unprintable colors. But it also is a colorspace that will include all colors that most good printers can print. It needs to be used if one desires a print that has those colors. So I'm upvoting. – doug Dec 20 '18 at 19:11
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Zeus's answer is great and comprehensive. I am just going to add some additional thoughts for some of the OPs specific questions. Some below are opinionated based on PRACTICAL REALITY and experience.

Avoid ProPhoto in Practice

I normally recommend NOT using ProPhoto. It is an ESPECIALLY bad choice for someone just starting out. And it is a particularly bad choice if your image destination is D65 (i.e. web or video) and not print (D50).

Reasons To Use ProPhoto

  1. You are going to print. Especially if the print process to be used is a high quality wide-gamut process using more than CMYK (i.e. hexachrome etc). Using ProPhoto in THIS instance allows you to remain in RGB mode to do your image editing (must use 16 bit per channel or more).

Reasons to NOT use ProPhoto

  1. Higher Delta E errors.
  2. Wider gamut than you can display.
  3. Impossible to accurately proof before print.
  4. Imaginary color primaries means you could inadvertently clip relative to output and not know it.
  5. Will still require transforms to another space.
  6. Converting to another space adds substantial workload to the flow.
  7. Requires multiple transforms to go from its D50 wp to the D65 used in web and video. More transforms means less accuracy, more losses, more problems.
  8. Unpredictable results because of all the above.
  9. Requires working in a higher bit depth.
  10. More predictable results can be had for most print outputs by converting to the CMYK colorspace (i.e. SWOP) and soft-proofing and delivering with the print profile instead of using an arbitrarily large RGB profile and crossing your fingers it might work.
  11. Provides no benefit in most scenarios.
  12. In other words, it adds complexity and needless work without actually providing a real benefit in most practical applications.

It's Not The Size It's How You Use It

The main reason people say use ProPhoto is a set of misconceptions. Here are some:

ProPhoto is a bigger gamut so it has more colors.

No, incorrect. The "number" of colors is defined by the BIT DEPTH. Technically, an 8 bit per channel sRGB image has up to 16.8 million colors. ProPhoto in 8 bit ALSO has up to 16.8 million colors. But those colors are spread over a LARGER AREA, so there is more DISTANCE between them. This does not result in greater fidelity, but it does result in greater errors (visibly as "banding").

ProPhoto won't clip your image.

Yes and No, but Not Usually Relevant. Yes, it is easier to clip in a smaller gamut space like sRGB. The next larger common space is Adobe98, and if you are clipping in sRGB, then Adobe98 might be the better choice for that image. But if you are going to web, you still need to get into sRGB, so you are going to need to adjust the image to fit into the sRGB space at some point.

The best way to not clip is to use an unbounded linear floating point working space.

Your Image Won't Lose Anything in ProPhoto

No, incorrect. You always have the potential to "lose" image data and fidelity. How much you lose depends on things like bit depth and how transforms to other spaces will be performed. When you use ProPhoto, you will have to make transforms to an output space, introducing errors for instance.

As mentioned above, using a space where the primaries are farther apart means that the available bits have more distance between values so each color is less accurately represented.

Also, since ProPhoto is a D50 whitepoint, you have to use the ICC PCS to convert to sRGB and a bradford chromatic adaptation. Going through the PCS can twist colors, clip, and cause other unpredictable results.

The better way to "not lose anything" is use SmartImage when opening RAW.

ProPhoto is better for HDR imagery

Again not true, it's more about bit depth. If you have very HDR imagery, bit depth and data type are important concerns. And again, the bigger the gamut, the MORE BITS you need to describe color values therein.

Side bar on bit depth

Not all 16 bit data containers are equal. There is integer, and there is float, and there is Photoshop.

Photoshop first, as it's a special case. PS 16 bit is actually 15 bit. That's still 35 trillion color values for RGB, but only 32768 "evenly spaced" levels per channel instead of 65536. This is enough for ProPhoto when gamma encoded, but not really for HDR imagery.

Other editors use all 16 bits, but Photoshop throws one bit away if you open those images in PS. Regular integer 16 bit is 65536 "evenly spaced" values per color. When I say evenly spaced, I mean in terms of numbers not gamma encoding. Integers are whole numbers 1,2,3,4 and no "fractions", i.e. decimals like 1.253

Another kind of 16 bit is 16 bit float. This is a floating point format, and DOES allow decimal values like 1.24345 the important different is this: in integer, each number is a whole number, and there nothing possible in between those whole numbers. With a float format, there is a LOT in between those whole number values, so you can "vary the distance" between color values in a more practical way than with integer math.

Floating point math allows working in LINEAR mode as opposed to a gamma encoded mode. This is actually more useful to prevent clipping and working with HDR than the colorspace.

Note that Photoshop is not so great for linear mode, but AfterEffects IS great for linear mode.

Pros use ProPhoto, so it must be best

No, Incorrect. Pros rarely use ProPhoto except for specific circumstances that may warrant it. This is especially true with current ADoughBee products that allow "Smart Images" when opening RAW, which is more ideal way to "not lose anything" than using ProPhoto.

Other Things

Setting Working Space OP's question on working space: You can set the working space in PS under colors, and you could set it to ProPhoto so you don't get that warning, but hopefully all here have sold you on the idea of NOT using ProPhoto for your application.

sRGB is the Standard for the Web sRGB is the standard colorspace for the worldwide web. Even if you don't tag your images, browsers will assume they are sRGB. CSS4 is going to introduce other colorspaces to the web (IMO that's a bad idea but whatever) but even then sRGB will be the DEFAULT.

The implication is that you need to end up as sRGB for EVERYTHING. And sRGB is FINE as a working space if it is not clipping your images.

Linear Space I work in Hollywood as an editor, VFX Supervisor, and Title Designer. We do most of our work in a LINEAR workspace, not a gamma encoded one. Photoshop does most things (8 and 16 bit) in a gamma encoded space, whcih is also how images are saved in jpeg, PNG, and TIFF etc.

Linear means NO gamma curve (curve power of 1.0). Linear requires floating point math (we use 32 bit float). The advantage of linear is that the math works the way light works in the real world. SO the math is simpler and also "more real".

Linear is virtually "unbounded" in that you can have colors much brighter than what would be maximum white in an integer image, and you can even have negative colors as are in some colorspaces (imaginary colors). this means that you essentially CAN'T clip.

Working in a linear floating point space is actually the IDEAL solution. Unfortunately Photoshop is kinda bad at it. Try Gimp if its interface doesnt drive you mad.

Adobe AfterEffects (AE) is surprisingly better than PS for linear (being driven by the film industry) but sadly Photoshop is stuck in its legacy ways. While AE is made for film/video, when I want to work on a still image in linear, I do it in AfterEffects.

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