Can RAW files be converted to different colour spaces?

[wideangle]

If I initially shoot RAW images in camera but have the camera set to sRGB, am I able to change this in my RAW converter to say Adobe RGB if I want?

[Jules]

Good question and I'll be interested to see the answer.

I think Adobe RGB is a larger colour space that sRGB, so maybe you can go from Adobe RGB to sRGB, but not the other way?

[ricktas]

Yes. but remember that if you convert from a smaller colour space to a larger one, then the missing colours are not just created magically to fit. So you can say go from Pro Photo to AdobeRGB to sRGB and each time you convert to the smaller colourspace you will lose some colours. But go sRGB to AdobeRGB to ProPhoto you dont magically acquire extra colours that did not exist in the first place.

[Calxoddity]

Hi,
I thought raw images didn't have a colourspace?

Regards,
Calx

[Jules]

Yes. but remember that if you convert from a smaller colour space to a larger one, then the missing colours are not just created magically to fit. So you can say go from Pro Photo to AdobeRGB to sRGB and each time you convert to the smaller colourspace you will lose some colours. But go sRGB to AdobeRGB to ProPhoto you dont magically acquire extra colours that did not exist in the first place.

So would you be likely to see banding as a result of converting from a larger to a smaller colour space?

[ricktas]

Not really Jules, what happens is the software finds the closest colour to the one in your photo and uses that, so it just cuts down the range of colours slightly each time.

[ricktas]

Hi,
I thought raw images didn't have a colourspace?

Regards,
Calx

They don't as such, but you have to give them one as soon as you work with it. Even displaying it on your screen. We are only now starting to see screens that can get close to displaying all of the AdobeRGB colourspace. But give it 5 years and we might be look at screens that can show ProPhoto space.

[wideangle]

So if I open a RAW image and then in the options click on the Adobe RGB colourspace (even though I have it set to sRGB in camera) that I can choose what colourspace I want it in before saving as a TIFF/JPG?

[Calxoddity]

Hi again,
Just to follow up my question further up, raw photos don't have a colourspace until you convert them to another format using a particular colourspace.

The in-camera setting is applied to the in-camera jpeg conversions, and does not affect the raw.

Once you have applied a colourspace to a resulting jpeg or tiff, making something small fit into a larger colourspace would appear to result in no gain (ie if you went ARGB > SRGB > ARGB through 3 generations of a saved tiff, the first ARGB image and the final one may have different colour if the shot was actually using colours in the full ARGB gamut originally).

I hope that makes sense!

Regards,
Calx

[ricktas]

So if I open a RAW image and then in the options click on the Adobe RGB colourspace (even though I have it set to sRGB in camera) that I can choose what colourspace I want it in before saving as a TIFF/JPG?

Yes, but as sRGB is a smaller colourspace when it goes to adobeRGB it will not be making full use of the gamut available in adobeRGB cause the data above what sRGB contained didn't exist to start with.

[ricktas]

Hi again,
Just to follow up my question further up, raw photos don't have a colourspace until you convert them to another format using a particular colourspace.

The in-camera setting is applied to the in-camera jpeg conversions, and does not affect the raw.

Once you have applied a colourspace to a resulting jpeg or tiff, making something small fit into a larger colourspace would appear to result in no gain (ie if you went ARGB > SRGB > ARGB through 3 generations of a saved tiff, the first ARGB image and the final one may have different colour if the shot was actually using colours in the full ARGB gamut originally).

I hope that makes sense!

Regards,
Calx

Exactly, BUT most monitors display using sRGB, so even though your photo in RAW doesn't have a colourspace, what you see on your screen is being limited to sRGB, even in your RAW converter. Gets confusing eh?

[wideangle]

Yes, but as sRGB is a smaller colourspace when it goes to adobeRGB it will not be making full use of the gamut available in adobeRGB cause the data above what sRGB contained didn't exist to start with.

Thanks everyone, ironically though most lab printers do not accept Adobe RGB colourspace, well none that I have dealt with yet. I suppose if you are doing a lot of your own printing then it may be a different story?

[ricktas]

Thanks everyone, ironically though most lab printers do not accept Adobe RGB colourspace, well none that I have dealt with yet. I suppose if you are doing a lot of your own printing then it may be a different story?

Ah, but most home printers cannot print the adobeRGB gamut either. In fact most cannot get the full sRGB gamut..can't wait for the future.

[clm738]

Isn't it better to set your camera to Adobe RGB and develop in RAW then convert to sRGB for printing or web use?

[ricktas]

You can develop in RAW whether it is set to AdobeRGB or sRGB, but yes it is better to save in sRGB for printing at web at this time.

However, firefox and a few other browsers are colourspace aware so if you view an AdobeRGB photo over the net using a colourspace aware browser, it doesn't really matter. But an AdobeRGB photo in a non colourspace aware browser (that just assumes photos are sRGB) will look flat and slightly less saturated.

[arthurking83]

I have to disagree with Rick on the raw colourspace issue.

A raw image is not colour aware. It's a collection of data that has yet to be converted into anything meaningful. There is a jpg image embedded in the raw data, that will be affected by the colour space you've selected in camera, but the raw data itself is not determined, even as you process the file on your PC(depending on what software you're using)

So if you choose a smaller color space(such as sRGB) in camera, the only file that is affected is the embedded jpg thumbnail, as the colour space is now set in that file, and any adjustment may look affected, but only in the jpg file. Any conversion of the raw image, to whatever format you later decide on in your editor is then determined by what you set the raw image too.
But that, once again, is only limited to the converted image, and not the raw image... if you have kept the raw image, you can subsequently convert it to any other colour space and you lose nothing.

The raw file is the key.. any converted raster image is set at the time of conversion, and shouldn't be changed to any other colour space, if colour accuracy is required. You'd set a raster image(eg. jpg/tiff) to a different colour space via the original raw file again.

Older Nikons all used to have various colour space settings that the user could select from, but in their later cameras(at least from the D300 and onwards, that I know of) they changed those variables to only two... from about 4 or 5. Now you only get the option of aRGB or sRGB.. for those users that are affected by colour space requirements, such as someone that shoots in jpg or tiff mode) the two options are enough.
Those that need ProPhoto colour space will almost certainly be shooting raw anyhow(but I don't know if that's an option in the Dx series cameras, definitely not an option in the Dxxx cameras).

This info is based on using the manufacturer supplied raw conversion software, as I have no idea on how third party software handles any colour space conversion, and this info has been supplied by a high quality photo printing lab here in Melb, and via some 'professional advice' on other forums.
(so technically it's limited to Nikon raw images, but I suspect that other manufacturers use the same principles too).

I used to shoot mainly in aRGB with my D70s, as I thought that was the better colour space to use if I ever wanted to print professionally(via this pro photo lab), and they explained this to me, I still started off shooting in aRGB on the D300, but then changed as the file naming gets all screwy and confuses me when I upload to the PC.

I just have to remember, that if I ever get any of my images printed at a pro lab, I need to batch convert the raw images to aRGB, as that's what they recommend, and then convert to the highest quality tiff format.

As a test, it's quite easy to try.
You can extract the embedded jpg image from the raw file(see RAW Extractor in this link.
Once you set the camera to a specific colour space, the jpg image is then set.
If you then subsequently change the colour space of the embedded jpg to something different(usually sRGB to aRGB makes the biggest difference), the embedded jpg looks yuk! Try it and save it as a copy.

You can then change the colour space of the raw image, many times over, and save it as and alternate file with a different colour space save it as a jpg file and then use a non colour space aware program to see how the embedded jpg can be affected by colour, where the jpg image form the raw image will not be, and will always look the same as the raw image(depending on quality settings of course).

[Calxoddity]

What Arthur said! Well done sir.

BTW, here's a link that clarifies some of the concepts around raw conversion: http://www.bythom.com/qadraw.htm

[ricktas]

Im a bit confused here, seems some think I have stated a RAW file has a colourspace, which I haven't ?!?!

[Miaow]

i think whatever you save raw as after as a jpg in a program as is going to make it have a colourspace - ie save it as srgb and will be etc hmm though if camera is set on a specific colour space i think that would more apply to a jpg

[monkey]

so how do you find out which monitors support aRGB and ProPhoto?

Currently I have a Samsung SyncMaster BWX and cannot find out via the online specs.

Do FULL HD monitors support all formats?