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aRGB to sRGB

PostPosted: Tue Oct 18, 2005 10:09 pm
by NJ
i know its probably been asked many times before, but can or how do i change my photos from adobeRGB to sRGB?

PostPosted: Tue Oct 18, 2005 10:19 pm
by leek
Hi NJ... In Photoshop, you just select Edit --> Assign Profile and select sRGB

HTH

PostPosted: Tue Oct 18, 2005 10:25 pm
by kipper
Actually wrong, you do Convert to Profile.

Assign will just take the image in it's current profile and assign a new profile to it without trying to best fit that image to the new color space/profile. As a result the image will subtly change color.

PostPosted: Tue Oct 18, 2005 10:27 pm
by stubbsy
Darryl's suggestion is better since it maintains the appearance of the image colours, whereas what John says can change the colours noticeably. If you have Nikon Capture it can be done there too.

PostPosted: Tue Oct 18, 2005 10:34 pm
by NJ
thanks very much guys!

PostPosted: Wed Oct 19, 2005 12:38 am
by oli
Surely you can tell your camera to assign the sRGB profile to files?

I'm assuming you asked because it is giving you aRGB files here...

PostPosted: Wed Oct 19, 2005 7:52 am
by leek
kipper wrote:Actually wrong, you do Convert to Profile.


That's what I meant to say... :oops:

Oli... you can tell your camera to work in sRGB, if you are shooting JPGs, but Adobe RGB can represent a much wider range (gamut) of colours.

People generally therefore capture and edit in Adobe RGB and only convert to sRGB at the last minute for display on the web.

PostPosted: Wed Oct 19, 2005 8:00 am
by kipper
Sorry John, didn't want to sound like I was coming off harsh either. It was a quick message in between jobs and a bit rushed :)

PostPosted: Wed Oct 19, 2005 8:02 am
by leek
kipper wrote:Sorry John, didn't want to sound like I was coming off harsh either. It was a quick message in between jobs and a bit rushed :)

Mine too... we found the right answer in the end :lol:

PostPosted: Wed Oct 19, 2005 1:25 pm
by oli
leek wrote:Oli... you can tell your camera to work in sRGB, if you are shooting JPGs, but Adobe RGB can represent a much wider range (gamut) of colours.

People generally therefore capture and edit in Adobe RGB and only convert to sRGB at the last minute for display on the web.


That is only relevant if you are shooting JPG the way I understand it. If you shoot RAW then it doesn't matter what profile you use in the camera because the profile tag only becomes relevant in post processing (ie. When you convert your RAW to TIFF or whatever it is).

It depends where you do your printing, in my experience some print labs want stuff in sRGB anyway so there's not much point in working with aRGB all the way through your image processing...

PostPosted: Wed Oct 19, 2005 1:56 pm
by leek
oli wrote:That is only relevant if you are shooting JPG the way I understand it. If you shoot RAW then it doesn't matter what profile you use in the camera because the profile tag only becomes relevant in post processing (ie. When you convert your RAW to TIFF or whatever it is).

Correct... As I said - if you are shooting JPGs :lol:

oli wrote:It depends where you do your printing, in my experience some print labs want stuff in sRGB anyway so there's not much point in working with aRGB all the way through your image processing...


My understanding is that you are better off editing in aRGB because it has a wider gamut. If you convert to sRGB early then you will lose colour information in your image. Every step in your PP will be operating on that reduced colour range, so you will probably end up with lower quality results. Personally, I'd preserve the aRGB in my PSD file and only convert to sRGB (if required) at the last step. Some experts even advocate using the Prophoto RGB colour space during PP as this has an even wider gamut than aRGB.

PostPosted: Wed Oct 19, 2005 2:55 pm
by NJ
My understanding is that you are better off editing in aRGB because it has a wider gamut. If you convert to sRGB early then you will lose colour information in your image. Every step in your PP will be operating on that reduced colour range, so you will probably end up with lower quality results. Personally, I'd preserve the aRGB in my PSD file and only convert to sRGB (if required) at the last step. Some experts even advocate using the Prophoto RGB colour space during PP as this has an even wider gamut than aRGB.

Yeah thats what i thought. I usually always shoot jpeg, only coz i can fit more images on the card, but always at highest res. I will continue to shoot in aRGB but will change to sRGB for web use. Thanks guys.

PostPosted: Wed Oct 19, 2005 3:00 pm
by oli
I guess in the end it all depends on what you are doing with your images, and what their final output is going to be.

Personally my photos are usually just for the web so my whole workflow stays in sRGB. If I really need to have something in aRGB for printing then I'll process the RAW file again for aRGB...

There's not really a "better" way of doing it as far as I'm concerned. It's just a matter of working with whatever profile suits your output best.

If anyone put two or three identical prints (ie 30x40 inch) prints infront of someone which were processed using two or three different colour profiles I doubt that most people could tell the difference. :)

Now to be a bit picky: If you shoot JPG then why even worry about colour profiles? In my opinion if you are concerned enough about the quality of your final images (large prints in particular) that you are debating colour profiles then you wouldn't be shooting JPG...

PostPosted: Wed Oct 19, 2005 3:36 pm
by NJ
This is all stuff i need to know so dont worry about whether your being picky or not, its all usefull information to me. I only asked how to change from one to the other because i had a picture that was aRGB and i needed to change it for the web. I think i'll do what you do, oli, as pretty much all of my photos go on the web, i'll go with sRGB. thanks for the tips.

PostPosted: Fri Oct 21, 2005 6:09 pm
by rallyant
Is this the same with all cameras?
I have a Canon 350 and it lets me set it to shoot in sRGB or AdobeRGB in RAW also.

Just wandering y it would let me do that if i can take eather colour space from the RAW file?

Glen

PostPosted: Fri Oct 21, 2005 6:13 pm
by oli
rallyant wrote:Just wandering y it would let me do that if i can take eather colour space from the RAW file?
Glen


It's just a tag for the file. It probably could be removed or locked but it doesn't really matter.

PostPosted: Fri Oct 21, 2005 6:34 pm
by MCWB
leek wrote:My understanding is that you are better off editing in aRGB because it has a wider gamut. If you convert to sRGB early then you will lose colour information in your image.

True, but the counter argument is that your monitor's gamut is smaller than aRGB (much closer to sRGB), so if your working space is aRGB you can potentially be editing colours that your monitor can't physically display. Works both ways unfortunately, 'aint no such thing as a free lunch. :)

In the end though, the 'right' workflow involves you getting correct colours where you want them, either on the web or in print, and I'd wager that 99.9% of the time it's not going to matter whether you use aRGB or sRGB.

PostPosted: Sun Jan 29, 2006 1:56 pm
by pgatt
I suspect it does the aRGB profile, along with sharpening that you set and contrast and color tones, to the jpeg, but when you shoot raw you're getting a jpeg formatted how ever your camera is set, and a raw file which is raw ie. unprocessed. Can someone with a dslr handy try the following - turn on aRGB on jpeg, and shoot a jpeg and a raw file together as normal, and then switch to sRGB and shoot both again. (I can't at the moment, my slr is being serviced)

What I suspect will happen is that both jpegs will have different profiles attached to them and the RAW will be no different, but may perhaps default to the shot profile as the default conversion option.

PostPosted: Sun Jan 29, 2006 3:11 pm
by oli
pgatt wrote:What I suspect will happen is that both jpegs will have different profiles attached to them and the RAW will be no different, but may perhaps default to the shot profile as the default conversion option.


You're right. It doesn't matter what profile you select in your camera if you are shooting RAW because colour profiles don't come into it till you are in the processing stage.

PostPosted: Wed Feb 01, 2006 12:23 pm
by Grev
So I guess there is not much point to use pro photo RBG unless you're making a print? If the photo was never intended for printing then the best choice is to stick with sRGB?