Photoshop, whats the best RGB colour space to use

i use srgb to save pratting around but i do a lot of stuff for web as well as print and my printer is calibrated to my screen so regardless of colour space as long as it comes out looking like what i'm seeing then i'm not too fussed.
 
sRGB

AdobeRGB only makes sense if

a) The image needs the extra saturation the colour space allows for
b) You work in 16bit
c) The output device can handle the larger colour space

Having a calibrated monitor is also very important otherwise you're playing paint by random number :(
 
Working in 16bit is only part of the equation, you also need to print in 16bit. Epson only have a few 16bit capable drivers for their high end models.

Printing with an 8bit driver could lead to banding in subtle gradients when used with AdobeRGB. The colour space might support 400 levels of saturation but 8bit can only represent 256 so it has to skip some of them in order to reach the limits. Using a smaller colour space like sRGB which was designed for 8bit images means the saturation and bandwidth are well matched. If the original image data had more saturation than the colour space allowed for then those colours will be clamped at max saturation.

Bear in mind that most images don't need the extra saturation of AdobeRGB and the differences are subtle anyway, most people wouldn't be able to tell one from the other.
 
pxl8 said:
Working in 16bit is only part of the equation, you also need to print in 16bit. Epson only have a few 16bit capable drivers for their high end models.

Printing with an 8bit driver could lead to banding in subtle gradients when used with AdobeRGB. The colour space might support 400 levels of saturation but 8bit can only represent 256 so it has to skip some of them in order to reach the limits. Using a smaller colour space like sRGB which was designed for 8bit images means the saturation and bandwidth are well matched. If the original image data had more saturation than the colour space allowed for then those colours will be clamped at max saturation.

Bear in mind that most images don't need the extra saturation of AdobeRGB and the differences are subtle anyway, most people wouldn't be able to tell one from the other.
Click to expand...

Hi,

Interesting discussion here, what's your opinion of pro photo RGB Pxl8?
Over the summer I had a client that specifically asked for 16 bit, Adobe RGB in camera colour space, working profile pro photo RGB, I submitted the images as a 16 bit TIFF in pro photo RGB which they later coverted to CMYK for press publishing.
I'll be honest I didn't 100% understand the reasons why I just did the do or die part.
My client was completely satisfied and when I saw the finished product in print it looked fine.
I'd like to understand a little more about these procedures, any wise words & wisdom would be appreciated.

T
 
Tomas Whitehouse said:
Hi,

Interesting discussion here, what's your opinion of pro photo RGB Pxl8?
Over the summer I had a client that specifically asked for 16 bit, Adobe RGB in camera colour space, working profile pro photo RGB, I submitted the images as a 16 bit TIFF in pro photo RGB which they later coverted to CMYK for press publishing.
T
Click to expand...

In camera colour space is pointless if you're shooting raw, the output from Lightroom, etc. is what matters which in your example ProPhoto.

If your outputting to a high end system for press, etc. then using a larger colour space makes perfect sense and the system can handle the colour depth and range. That's where the larger colour spaces really come into their own and has lead to the idea that they "give you more colours and are better" as, after all, more is better isn't it?

In an 8bit bandwidth a red value of 255 is full saturation of red. Now if you compare red values between sRGB and a larger space such as AdobeRGB or ProPhoto to get the same saturation you need a much lower value, maybe 230 and 200 respectively. Now if the saturation in the image only needs the 255 level of sRGB then using a larger colour space means you're throwing away data. The larger space doesn't have values above 230 or 200 but still needs to represent all the levels up to that point so instead of 0-255 you've only got 0-230 or 0-200 and that can produce banding in gradients - you've got fewer values to represent the transition from zero saturation to full saturation.

Note this is exactly why images posted online in AdobeRGB look dull and lose saturation - a given RGB value represents less saturation which would normally be converted by the colour management system to the correct value for your display profile.

So what happens when the image does need more saturation that the large space offers? 255 in AdobeRGB might need a value of around 280 in sRGB to display the right amount of saturation but of course in 8bit you can't go that high so instead all the values are clipped to 255 (actually it depends on what mode you set the colour management to but for simplicity I'll stick with clipping). So now you're gradient in sRGB loses some tonality at the top end but still has the smooth gradient to that point. In AdobeRGB you have an evenly space gradient but the banding is still there - remember AdobeRGB is going further in the saturation but still only has 256 steps to get there.

The working space should always be the smallest one you can get away with for the image data. If you put the image into a larger space you don't get more colours, you get the same colours but with less tonality because the working space has to save headroom for more saturation. It's like having a room 10ft tall, you might get a few people who are approaching 7ft in there but you've still got 3ft of space that's never going to be used. Better to have a room only 6.5ft tall and have a few people duck (clipped colours). In some situations the clipped colours might be vital and a larger space is needed but when that happens you really need to think about using 16bit colour with 16bit output devices to prevent the banding issues, something your client was able to deal with. For most of us, printing on inkjets or using photobox, etc. we're stuck at 8bit and images that don't need the larger space anyway so all we're doing is trading tonality for satuation values that aren't being used.


Jayst84 said:
I shoot in Adobe 1998, process in Adobe 1998 / 16bit, then convert to custom profiles for printing. I don't see why you would choose to throw away information from the beginning, never know when you may want it.
Click to expand...

See above, having the data in 16bit doesn't solve the wasted space issue, it just means you can measure it more accurately.
 
The simplest test would be to produce 2 images , one in sRGB and the other in Adobe RGB. Keep them all 8 bit as I don't know if you printer can handle 16 bit files.

Print both images and see if you can see a difference. Look at saturated Reds and Greens, I don't know if you'll see anything in the Blue axis.

I tried to find a profile for the 1400, to compare it with the colour spaces for Adobe and sRGB but couldn't, so I think it's down to a visual test.
 
Of course you need to use an image that uses the extra saturation in the first place or there won't be any difference (y)
 
Cheers Pxl8, I've just got back home from being on the road since Tuesday, thanks for the detailed reply, I seriously appreciate it (y)
 
You must log in or register to reply here.
Back
Top