Editing sRGB in AdobeRGB color space?

[Abitconfused]

So, as recommended by some, I should edit sRGB images within the AdobeRGB color space so the editing is accomplished in a larger space preventing colors from going out of gamut. But, what difference does that make if the image needs be reconverted back to sRGB for the internet? And ProPhoto RGB is this the best space for RAW?

[Manfred M]

So, as recommended by some, I should edit sRGB images within the AdobeRGB color space so the editing is accomplished in a larger space preventing colors from going out of gamut. But, what difference does that make if the image needs be reconverted back to sRGB for the internet? And ProPhoto RGB is this the best space for RAW?

If you have an sRGB image, there is no real advantage to converting it to AdobeRGB or ProPhoto as your data is constrained by the colour space you started with. It can be argued that you might have a bit more headroom if you are manipulating colours, but in a practical sense I have not really seen this make any difference in practice.

ProPhoto is the widest colour space and a version of that is the default colour space used by Lightroom). The main problem with it is that no computer screen or printer can properly output this colour space, so any out of gamut colours have to be handled by the rendering intent of the computer or printer driver. What that means is that sometimes we will get colours that will surprise us because they don't look quite the way we expected them to. This tends to be more of something we see when we print, rather than on screen.

I tend to default to using ProPhoto all the time, but I have been warned that it is NOT a good colour space to use when preparing work for a conventional offset printing press that uses the CYMK colour space. The conversions from ProPhoto to CMYK seems to produce colours that are off a bit. As very few photographers have their work printed on offset presses, most of us won't have to worry about this issue.

If you are using a regular gamut screen, you are going to be seeing colours rendered as 8-bit sRGB anyways. If you have a wide gamut screen (hint - that's what I use) and have any AMD graphics card or an nVidia Quadro (workstation) graphics card, your colours will be rendered correctly as 10-bit images AdobeRGB images. For some reason nVidia's drivers in consumer cards do not properly handle Photoshop colours and this is clearly stated on their website.

The other issue that we have not looked at is the bit depth that should be used with these colour spaces. ProPhoto should always be used in 16-bit, otherwise you are likely to see artifacts (much like we see when editing 8-bit jpeges). You can get away with 8-bit in both sRGB and AdobeRGB, but if you are working with raw data, you will be throwing away a lot of the data your camera has captured. Depending on the specific camera model, raw will be either 12-bit or 14-bit. Some medium format cameras claim they are true 16-bit, but I don't know a lot of people who shoot with those regularly.

Finally, unless you are using Mozilla FireFox, all of the other web browsers out there are not particularly well colour managed, so saving anything that goes on the web as an 8-bit sRGB image will work. Anything else is going to be dependent on the browser that the viewer is using.

[Mike Buckley]

Finally, unless you are using Mozilla FireFox, all of the other web browsers out there are not particularly well colour managed

That was my anecdotal experience four years ago but I haven't seen anything definitive about that since then. Do we know with great certainty that none of the other widely used browsers have caught up to Firefox's color-management capabilities?

[Simon Garrett]

That was my anecdotal experience four years ago but I haven't seen anything definitive about that since then. Do we know with great certainty that none of the other widely used browsers have caught up to Firefox's color-management capabilities?

Last time I checked PC browsers (a couple of months ago), this was the status of those I checked:

• Firefox, Chrome, Vivaldi and Safari are all colour-managed properly. That means they use the profile embedded in the image, and the profile of the monitor, and convert properly from the image colour space to the monitor's colour space.
• IE and Edge are still not properly colour-managed. They use the image profile, but not the monitor profile - instead always converting the image to sRGB. This works roughly OK for normal-gamut monitors, most of which have a colour space similar to sRGB, but is hopeless for wide-gamut monitors. Note that most colour management test pages will work OK for IE and Edge, as generally they test only if the image profile is used.

There's a further problem even for properly colour-manged browsers: by default, they colour-manage only if the image contains an embedded profile. Many images do contain profiles, but most graphic elements on the web (banners, backgrounds and so on) are often gifs or other file types and without embedded profiles.

Firefox has an additional option (not the default) to make it assume that any graphic element (image or other) without a profile is sRGB, and colour-manage accordingly. To do this, set option gfx.color_management.mode to 1 from its default 2 (put "about:config" as the URL and you get a page with all Firefox's advanced options, type "gfx" and it lists those with "gfx" in them to save scrolling through hundreds, double click gfx.color_management.mode to change its value).

This (seting gfx.color_management.mode to 1) makes relatively little difference for normal gamut monitors, but is important for wide-gamut, which is (IMHO) why Firefox is still the only well-behaved browser for wide-gamut monitors.

[Mike Buckley]

Very informative, Simon. Thank you!

[Abitconfused]

Wow!

[george013]

I wanted to post this link in another thread, but the site was off-line. Now it's on. I posted it before.
http://regex.info/blog/photo-tech/color-spaces-page1

George

[Mike Buckley]

Note that the date of the blog George's post brings to our attention is more than ten years old and is surely out of date.

[Black Pearl]

A quick addition to Simons excellent post - Safari is now colour managed on both macOS and iOS platforms so if you have a wide gamut iPhone or iPad you will see embedded profile images correctly the same as on an iMac/MBP

[xpatUSA]

So, as recommended by some, I should edit sRGB images within the AdobeRGB color space so the editing is accomplished in a larger space preventing colors from going out of gamut.

In a good editor, the image data that you edit remains in a wide color space. like Kodak ROMM.

What you see on your screen is that file transformed but not converted to whatever you're using as the working space.

But, what difference does that make if the image needs be reconverted back to sRGB for the internet?

So, unless you've actually converted the file to a smaller color space, you can edit away, making "round trips" out-of-working-space-gamut and back in without damage. But, if your editing has left stuff out-of-target-gamut, damage will occur the instant you convert to a "lesser space".

And ProPhoto RGB is this the best space for RAW?

As worded, that question will get you lots of different answers. George might tell you that RAW is not a color space and he would be right.

My raw converter brings in raw data and converts it to an input-referred linear RGB file format such as Kodak RIMM and that is what gets messed with, while editing. Kodak ROMM (aka ProPhoto) is an output-referred color space which can even be embedded as a profile a JPEG, not recommended though for color-management reasons already mentioned here.

My memory is getting hazy on these matters, so the well-respected and extremely knowledgeable DigitalDog might be along shortly to apply corrections.

[dje]

I remember reading an article by DigitalDog in which he explains that with Lightroom/ACR, raw editing is done in a linear form of ProPhoto RGB. You have no choice with this. The colour space choices in LR/ACR determine the colour space used for export.

Dave

[DanK]

I remember reading an article by DigitalDog in which he explains that with Lightroom/ACR, raw editing is done in a linear form of ProPhoto RGB. You have no choice with this. The colour space choices in LR/ACR determine the colour space used for export.

Dave

I believe that is correct. The color space is not modifiable.

[george013]

Note that the date of the blog George's post brings to our attention is more than ten years old and is surely out of date.

The bible is older and still many peopl read it

The valuable part of that article are the background and the tools. Even if you're not interested in the background than still you can find out what your browser/pc is doing at this moment. Maybe even used by Simon.

George