sRGB v Adobe RGB, Pro Photo etc..

[GaryMarsh]

I am always being told by more experienced photographers out there that if I want the best colour quality I should shoot in Adobe RGB (1998) or whatever because I will get more of the colours within the gamut as opposed to the sRGB colour profile. I am no expert, photography is just my hobby, but from my experience of using both profiles I can't see any difference when I get them back from the printers and this is on a high end printer I must add.
I only see the difference on my monitor when I am in editing mode and I switch between the two colour profiles Adobe RGB being much richer in colours but this doesn't extend to the final output, also when you are printing out an RGB image the CMYK colour gamut of the printer is smaller than the RGB colour space from what I have been told and this can make your Adobe RGB colour images look more muted.
So my question to the experts out there is wouldn't it make more sense to just use sRGB and have done with it?

Regards
Gary

[MilT0s]

Well Gary the answer is yes and no...

Yes, in the end you always have to convert your image to the much narrower CMYK your printer supports or to the also narrower (but less) sRGB in order to upload it to the internet.

However shooting and post processing in ProPhoto (better than Adobe RGB) gives you much more flexibility when editing since you can alter colors, sharpen, blur, denoise and do all this kind of stuffs with less danger to introduce posterization and other artifacts and obtain smoother results in general.

Another parameter to keep in mind is that things might change in the future as we will probably have better printers.

[MilT0s]

Another answer is: if your equipment supports it shoot in RAW. Raws don't have a color space assigned. You convert to a color space only when exporting to photoshop or creating a tiff, psd, jpg etc file in general.

[RSPIII]

... but from my experience of using both profiles I can't see any difference when I get them back from the printers and this is on a high end printer I must add.

I too am a bit of a novice Gary. Still, the difference should be fairly easy to detect assuming the printer and the paper are capable of reproducing the color space and ... and ... the software behind the print operation is using the right profile. What is the gamut of the printer? What is the gamut of the paper? Does the software know this?

Rob.

[orlcam88]

You hit it on the head. There's no printer (yet) that can print in RGB. Sure you'll get more colors in RGB but every output format are not in the RGB range. ICC profile for web (jpeg) does help though. The reason why they say to use RGB is because it "has" the wider gamut and overlaps the CYMK colors. sRGB and CYMK have parts that do not overlap. This is mostly in the green area. You can see this in the graph:
https://www.cambridgeincolour.com/tu...conversion.htm

So although RBG is wider color range, you'll have more to adjust for print than you would if you shot everything in sRGB.
I'm not sure if you are using PS or LR, but both of these allow you to preview the image in the CMYK gamut. If the color doesn't appear as you expect it, then you can adjust them. So for better print output, it's best that you send the images with the print color adjustment as you want it rather than letting the print service do it. Most do a good job of converting but there will be times where it just didn't convert them as you wanted.

I rarely print my photos but I learned alot about it. My personal reason for shooting in RGB is because technology changes and improves. At some point in the future, the print gamut will catch up. There are monitors that have RGB range now that didn't exist a few years ago. The web color space has been slowly catching up with firefox, IE allowing imbedded color space. To me it's future proof for a few years....until...The larger color space called prophoto starts to get popular!

[DanK]

You have some very good answers. I'll add to them by concrete example. I will use Lightroom for the example, so the details may vary.

I shoot raw, so there is no color space. Llightroom works in Melissa RGB, which is a variant of ProPhoto RGB, the largest of the three main color spaces. This is for the reason Mitos says: to minimize artifacts when editing.

When I export for the web, I use sRGB, which is the web standard. I see no difference between the jpeg and edited raw image on my monitor. This is because my monitor (a standard one, not a wide-gamut monitor) displays sRGB. So while I am working on the image, AFAIK, LR is rendering it as sRGB for my monitor.

Now, let's say I want to print an image, and I soft proof--that is, I tell the software to do its best to emulate the combination of printer and paper that I will use. If I put the original and the proof side by side, I will often see a difference. It is a striking difference when I am using matte paper. This is because the gamut of the matte paper is quite small, and the original image I see on the screen can't be fully replicated. I can edit the proof to make it closer, but I can't get 100% there because the printer can't reproduce certain colors on that paper.

but from my experience of using both profiles I can't see any difference when I get them back from the printers and this is on a high end printer I must add.

I am not entirely certain what process you are describing, but this is not terribly surprising. if the image has a color space embedded, the printer should try to map from that color space to the ICC profile of the paper. It will map differently, depending on whether the image has sRGB or aRGB embedded. If you are sending to a lab, some will only accept sRGB, but others (e.g., Bay Photo) will accept either one, and you should not see a big difference in the results.

So, my process is:
--shoot raw. This is only one of many reasons to do that.
--edit in the largest color space available. For example, when I have to export from LR to do external editing, such as focus stacking, I export TIFFs in prophoto, not sRGB or aRGB. If the software does not make the translation, they look awful on my monitor, but that gets taken care of later, when I bring them back into LR or other software that translates correctly for my monitor.
--For printing on my own, I don't reduce the color space. I let the software do that in the printing process, using the correct ICC profile for the combination of printer and paper.
--For printing at a lab, I convert to aRGB if the lab allows it because it is a larger gamut than sRGB, but I doubt this really matters.
--For the web, I convert to sRGB

[scriveyn]

A couple of questions

... I shoot raw, so there is no color space. ...

There are sensors for red, green and blue in the camera, so, isn't RAW a form of RGB colour space by default? - RAW captures "the amount of light" captured by each sensor. So, while standard RGB has a range of 256 values per channel, what range has RAW? Different for each camera make/model?

Where does Lab stand in this? Do I loose gamut converting from RGB to Lab for some processing and converting back to RGB (with a range of 256 per channel respectively)?

Hope these questions aren't altogether bonkers

Thx,
Frank

[MilT0s]

Bonkers? Not at all. Actually I think you are asking the right questions, I bet you have an engineering or science background.

As you suspected the range for RAW depends on the camera. Where importing to a computer the softwares needs to translates the raw data to a standard that every computer understands. The way these R-G-B informations from the photosites of the sensor are transformed into pixels is called demosaicing. You can find more details in wikipedia.

Lab is yet another way to represent the color of each pixel but after demosaicing. You loose data only when you convert to a color space that is narrower than the initial one even partially for some colors only, eg the reds.

Lab is wider than sRGB and adobe-RGB and I think (not sure) ProPhoto. So if you intensify of saturate for example the color of an image in Lab and then convert it back to RGB you might see some alterations on the image.

Keep in mind however that the process is limited not only by the color space conversion but also by the limited color range of you monitor. Many colors in ProPhoto and Lab can not be displayed in any monitor or printing device.

[scriveyn]

Thanks Miltos, I hadn't been aware of demosaicing. I have dipped into the Wikipedia and CiC articles and things are much clearer to me already. (Math rulez )

Lab/RGB: That's fine then. From the posts above I was aware of the display/print limitations, so, not loosing information during processing in Lab is good enough for me. - I prefer sharpening the L channel only over sharpening via USM in RGB.

Cheers,
Frank

[Manfred M]

This is always a highly debated subject and frankly in my testing, I find that theory in generally gets put down by reality.

1. The human eye can see a maximum of around 10 million distinct shades.

2. The very best printer create colours out of 9 (Epson) and 12 (Canon) cartridges. Not all cartridges are used for a specific print run; Epson uses a maximum of 8 and I don't know what Canon does. Regardless, colours are achieved by varying drop size and inks using a CMYK colour scheme, so the maximum number of colours that can be reproduced lies in the several hundred thousand range. The brightest white comes from the colour of the paper you are printing on.

3. Most lower end computer screens use TN (twisted nematic) native 6-bit and use a technique called dithering (i.e. a simulation technique to get up to 8-bit colours. At best they can represent the sRGB colour space. More expensive screens use IPS (in plane switching) technology which is native 8-bit and uses dithering to get to 10-bit (and beyond) colour space. Some of these are capable of displaying a high percentage of the Adobe RGB colour space. I am not aware of any monitor that displays ProPhoto colour space, not that we would be able to see in and reproduce it anyways.

So, why use ProPhoto versus Adobe RGB versus sRGB? Really for the same reason people shoot RAW rather than jpeg or edit in 16-bit rather than 8-bit. It give you more headroom. You won't necessarily need it or see it, but there could be times that you do. ProPhoto is a closer match to what a modern sensor captures than AdobeRGB (and even more so than sRGB) is, so if you shoot RAW, it makes sense to use this colour space and then down-convert as the last step of your workflow.

Then of course there is reality. I've tried different combinations and in the end found that usually I can't tell the difference in the final product in cases where the PP work is fairly subtle and minor. If you get into fairly major surgery, then it can make a difference.

[loosecanon]

There are two aspects to this
sRGB is the standard to which most commercial equipment is built for, its in some ways the minimum that should always be capable of proper display. So if you display your jpegs on a TV or standard monitor or digital projector they will by default look right. Adobe RGB will display more colours on a suitable monitor or other device, that has been calibrated to display AdobeRGB, and yes it will sometimes not clip colours in the same way as sRGB, but most display devices will not be able to display the full gamut and so you will not be able to see all the image rendering.
What is more important is that when you develop a raw image you can have a 16bit colour space with much more subtle graduation, which when you subsequent adjust brightnees, contrast and so on will retain detail rather than become areas of flat colour. If you shoot raw and jpeg as I do then raw is for images I wish to edit, and jpeg can be sRGB and used easily with no other processing, colour space conversion and so on.

[MilT0s]

Frank since you are a mathematician the short answer I guess could be:

[a wider color space is beneficial] for more efficient advanced interpolations while post processing your images (thus smoother results) and for hopping for better printers and monitors in the future.

[GaryMarsh]

Thanks for your reply most helpful.

[GaryMarsh]

Thanks for your help much appreciated, I do mostly shoot in raw so like you say when technology advances I will always be able to convert to the wider colour gamut and get the benefit.
Regards
Gary

[mahfoudhhi]

Gentlemen:
I found excellent answers in this subject for the question, but I could not understand one thing, if I shoot RAW it will not matter whether I chose Adobe RGB or sRGB in the camera setting (is what I understood right?) if yes, why is that please?
Thank you in advance.

[MilT0s]

if I shoot RAW it will not matter whether I chose Adobe RGB or sRGB in the camera setting (is what I understood right?)

Yes it doesn't matter, it a setting for shooting jpgs only.

The same accounts even for color temperature with a big difference. The color temperature affects the preview image in the LCD of the camera and is written as metadata to the RAW file. This way when you import the file to a computer, say with Lightroom, the program reads that data and applies the setting automatically when demosaicing. You can of course change that without modifying any data, just the interpretation of the RAW data from the program, unlike the jpgs.

That's why it's called RAW data and they didn't find a more delicate name after all.

[mahfoudhhi]

Yes it doesn't matter, it a setting for shooting jpgs only.

The same accounts even for color temperature with a big difference. The color temperature affects the preview image in the LCD of the camera and is written as metadata to the RAW file. This way when you import the file to a computer, say with Lightroom, the program reads that data and applies the setting automatically when demosaicing. You can of course change that without modifying any data, just the interpretation of the RAW data from the program, unlike the jpgs.

That's why it's called RAW data and they didn't find a more delicate name after all.

thank you very much Miltos for you nice answer. I understood now.

[charzes44]

Hi Gary,

In order to get the best out of your photos you will have to invest in a printer and make your own prints. High St labs are set up for the average (sRGB), and, therefore you need to have your camera set to sRGB also for them to produce something reasonable! However, when you produce your own prints on your own printer, you can utilise all the advice given above.

[mahfoudhhi]

Hi Gary,

In order to get the best out of your photos you will have to invest in a printer and make your own prints. High St labs are set up for the average (sRGB), and, therefore you need to have your camera set to sRGB also for them to produce something reasonable! However, when you produce your own prints on your own printer, you can utilise all the advice given above.

Thank you Charles. I have Epson R3000. is it good enough?

[MilT0s]

Hi Gary,

In order to get the best out of your photos you will have to invest in a printer and make your own prints. High St labs are set up for the average (sRGB), and, therefore you need to have your camera set to sRGB also for them to produce something reasonable! However, when you produce your own prints on your own printer, you can utilise all the advice given above.

Charles setting your camera to sRGB (if RAW is not supported) is not the optimum choice. You just have to soft proof your images with a ICC profile provided by the lab or if not any with sRGB before sending them the file. That way you can have a high quality file for future use and PP and another version for sending to the lab. You cannot expect great results from a lab without correct soft proofing. The CiC tutorials on that are (as all of them) fantastic.

I wish I had an Epson R3000 :-)