Which is better SRGB or Adobe rgb

[Saphire]

What is the best mode to have my camera set sRGB or adobe RGB, I seem to think it should be adobe am I correct.

saphire

[nigelblake]

SRGB is best for general use such as home prints etc, it is the system used for displaying images on the web.
Adobe RGB is the colour space that is used for images that are intended to be published as it will convert to CMYK more readily, Adobe RGB images are pale and lack saturation and will need more post processing to get the best results, they also will need converting to SRGB for web use.

[Saphire]

Thanks Nigel, my camera was set for SRGB I then changed it to Adobe RGB. I couldn't remember what was the better setting. I will put it back to SRGB as I post most of my photo's to web. When I open in adobe they are changed to Adobe RGB so I will change that to SRGB as well. Oh! this is complicated.

[Art Thorn]

My limited understanding of colour spaces, or 'gamuts', has been gained in reading many articles on the topic. Unfortunately I forget much of what I read just once, but from what I have gleaned colour spaces such as AdobeRGB can be larger (contain more colours) or smaller. I have never heard anything about lack of contrast, etc., and I use Adobe RGB for direct manipulation in Photoshop. My understanding is that AdobeRGB is a larger colour space than SRGB. There are several excellent articles referenced in Luminous Landscape. Check their website and do a search for colour space. Photoshop's digital manual also has several articles on the topic.

[Saphire]

I have now done quite a bit of reading on the subject and I have come to the following conclusion. I shoot only in Raw and do all my processing in Photoshop because Raw is in fact a file with maximum colours. In the camera RAW ignores the SRGB and Adobe RGB setting, so don't have to worry whether its in the correct setting unless I shoot in Jpegs . If I am wrong please come back and correct me.

[Art Thorn]

Well Christine, that makes perfect sense, but I've never thought of it. I use Phase One (LE) raw converter, and now that I do think of it, I've never worried about colour space in that. It only seems to become an issue when I'm creating TIF files and printing (maybe???). Have to back and look!

[compa]

I have now done quite a bit of reading on the subject and I have come to the following conclusion. I shoot only in Raw and do all my processing in Photoshop because Raw is in fact a file with maximum colours. In the camera RAW ignores the SRGB and Adobe RGB setting, so don't have to worry whether its in the correct setting unless I shoot in Jpegs . If I am wrong please come back and correct me.

You are correct ... to a point. RAW does not have a color space assigned but you must assign a color space to the photo upon converting to tiff or jpeg (which is something that must be done sooner or later).

You are simply delaying the decision of which to use. As for deciding which is best for you, I researched the issue a while back and wrote up my findings on my blog > Please check it out: http://www.jbs-blog.com/?p=85

One note I have to make in response to some of the other posts - Adobe RGB and sRGB both have exactly the same number of colors! The difference between the 2 is in which colors they contain - not in how many. sRGB has finer differences in the colors while aRGB represents a slightly wider gamut of colors (at the cost of accuracy). Properly processed, aRGB is not less saturated than sRGB - they only appear that way when improperly displayed on the web which assumes all photos to be sRGB.

Here's another explanation (from professionals) of the sRGB and Adobe RGB situation: http://www.smugmug.com/help/srgb-versus-adobe-rgb-1998

[robski]

Jim you have managed to grasp the hub of a very complex subject. For the past 80 years various attempts have been made to define colour. All attempts define it as a 3 dimensional model. Some models are wheels, sphere or cylinder shaped (the space within these objects will be referred to as the colour space). Hue, saturation and lightness demonstate that visible colour is 3 dimensional. These attributes provide three coordinates that can be used to map visible colour in a colour space.

So in essence a colour space is a range of colours contained within boundries. The colour space maybe "device dependent" i.e the range of colours produced by printer inks or the phosphors on a CRT. Therefore the colour range will change for every individual device. Other colour spaces are referred to as device independent. These provide a means of producing a repeatable standard (meant to contain the full range of visible colours). They are often used as a transitional space or images are stored in that space. A transitional space would be used when converting from a camera or scanner colour space to a printer or CRT colour space.

As Jim has indicated the Adobe rgb space contains more blues and greens than the srgb space because CMYK printing inks can produce this range of colours whereas the phoshors on a CRT cannot.

OK the space defines a range of colours.

Now Profiles is where it starts to get complicated.

Profiles are in essence colour remapping tables and can be used to deal with a number of situations. These tables are often 3 dimensional and can be thought of as a colour cube. There maybe more than one set of tables in the profile to deal with different situations. The first is simple colour correction. Others deal with colours that fall outside the destination colour space. Basically there are 2 options to deal with this. The first is to preserve colour within the boundry and then clip colours outside the boundry to the boundry. The second is to rescale the colours so that everything fits within the destination space to give a more natural photo effect (this can make the image look toned down).

As another source of info

A link to download a pdf from Canon on colour management
http://www.cps.canon-europe.com/articles/article.jsp?article.articleId=100226

Rob

[Saphire]

Thanks everyone, It is beginning to sink in although I will probably forget in a few months (An age thing). At least now I know I only have to use the correct setting in the 350D camera if I shoot JPEG. Raw ignores this setting except if I shoot RAW plus fine JPEG. I shoot purely Raw when I do a save for the web in Photoshop the best is in SRGB and if I want output to proof, save in ARGB.

[stuartlawrie]

Personally the line I take is to shoot in Adobe RGB as I don't know to what use the image will be put until later, if I then want to put it on the web, I can afford to disgard the unnecessary data by converting to sRGB, however if I have discarded it already at the shooting stage I cannot really put it back later in photoshop.
Its also worth noting that most of the agencies that sell photos want them in Adobe RGB, and yes as I found out to my dismay when I submitted my first digital images to Photega, they can tell if you have converted it back!

[robski]

I thought I would post some examples so you can see the effect.

going from left to right

1) camera set to Adobe RGB
2) camera set to sRGB
3) number 1 saved as web windows setting
4) number 2 with an Adobe RGB profile applied
5) Image as per spectrocam readings of the target

These show how they are on screen not how they would print.



Rob

[robski]

Spectrocam version of target now added

Rob

[Art Thorn]

This is getting more and more interesting. I read more and think of more questions. Something that I just saw suggests that I save my files (tif or photoshop format) with the embedded camera profile. Phase One has profiles for each camera that are obvious (I think Camera Raw has them too but they are not front and centre) and the suggestion was to stick with the native profile and not convert to anything??? I just have to keep reading, as this difference between profiles and colour spaces just isn't clear to me yet. At what stage do you pick a colour space Rob?

[compa]

This is a horrible subject! 99% of photographers never even need to know that this subject exists!

OK ... I'm not sure what the posted photos are supposed to show considering that almost everyone is going to be viewing them in a browser that is not color space aware and defaults to sRGB. They will see a difference but that difference will be different for everyone since they are not using calibrated monitors! It is almost impossible to show the differences between colorspaces over the internet.

Using camera color spaces is generally considered a no-no. The Pro-Photo RGB space is the preferred standard and matches (almost exactly) the Canon 20D space (It exceeds Nikon spaces). This color space is greater than that of any printer in existence. This article does a good job of explaining a few things: http://www.outbackphoto.com/color_management/cm_06/essay.html

Using a color space that is larger than you need is not a good idea. If you will be doing much editing, you are leaving yourself open to banding and posterization in your photo when using these larger color spaces. There is a cost for everything.

Basically, unless you are doing fine art printing (or selling your photos to an agency) use sRGB. Using any other color space requires that your editing system be setup properly and that your monitor be calibrated on a regular basis. Not to mention, that you fully understand all this mess!

Most computer users and photographers don't even have their brightness levels set correctly on their monitors!

[robski]

This is a horrible subject! 99% of photographers never even need to know that this subject exists!


Jim you have hit the nail on the head. The vast majority of shots are for amateur use and will be either be destine for web, 4 x 6 photos or home printer. For these srgb is the best setting.

The posted photos were simply to illustrate the effects of using different colour spaces and profiles.

If the shots are intended for professional use then take advice from the publishing house or agency on what format they want the image in. Normally a High resolution 16 bit Tiff with no processing done by you. The pre-press studio department will process as required to calibrate to their press.

Rob

[Art Thorn]

After much more reading, and learning to use photoshop's soft proofing properly using the actual printer/paper profile for that purpose, and the out of gamut warning, I am convinced that the best way to go is to use the actual camera colour profile all the way up to the last minute, the print. Since I am not really interested in posting on the web (my connection is too slow for that and it is a terrible waste of 300f2.8 resolution capability) this system works best for me. But thank you for getting me going down this road. I have learned a tremendous amount.

[christineredgate]

Phew,fascinating,complicated!!!.to think all I do is point ,shoot,enhance and print,and all that work re colour has been done for me via one camera and one small card,and a pc.Amazing.You guys certainly know your stuff re the ins and outs of technology.