sRGB to a wide gamut printer?

[Messiah Khan]

Right, I know what happens when you use AdobeRGB to display to a low gamut device. It clips the colours, making them look muted. But what happens when you go the opposite way? Ie, you print an sRGB image to a wide gamut printer. Does the image simply not achieve the maximum colour range possible, so therefore also look muted? Or do the colours 'stretch' to fit the new gamut, therefore causing banding? Im trying to do a digital photography handout, but im confusing myself on this issue. :shrug:

 

[EOS_JD]

The low gamut image will print fine as the printer can match the whole gamut. Why would the printer stretch it?

 

[Messiah Khan]

The low gamut image will print fine as the printer can match the whole gamut. Why would the printer stretch it?

But then lets say the pure red ink would be 'watered' down to produce the red that the sRGB gamut can produce, making a more muted image compared to that of a AdobeRGB image. Is this the case?

 

[alexkidd]

there are plenty of explanations out there on the web but suffice to say as long as your screen and printer are calibrated correctly and profiled there won't be a problem

 

[Messiah Khan]

there are plenty of explanations out there on the web but suffice to say as long as your screen and printer are calibrated correctly and profiled there won't be a problem

I realise this, even though it's not quite right. There is a lot more to colour management that making sure the screen and printer are calibrated correctly. Colour space is a seperate issue, then there is ink matamerism etc. I basically want to know what happens mathematically when you print a low gamut colour space image to a wide gamut output device.

 

[EOS_JD]

But then lets say the pure red ink would be 'watered' down to produce the red that the sRGB gamut can produce, making a more muted image compared to that of a AdobeRGB image. Is this the case?

What printer has "pure red ink"?

Learn how printers make their prints. I don't think your sRGB image will be affected. Calibrate your monitor and you should get what you see.

 

[pxl8]

I basically want to know what happens mathematically when you print a low gamut colour space image to a wide gamut output device.

The range of colours isn't stretched to fit the size of the printer's space, they stay the same. In one sense you could say the colours were muted as a result but only relative to the available saturation of the larger space, they haven't really changed - assuming a calibrated screen then the result should match.

If you want to use the full saturation of the printer's colour space then use a larger space for the image during the processing stage. Banding can be an issue with larger spaces because you still have 8bits to represent more colours unless the printer driver fully supports 16bit image data.

The golden rule is to use a colour space smaller than the output device but big enough for the colours in the image.

 

[Messiah Khan]

What printer has "pure red ink"?

Learn how printers make their prints. I don't think your sRGB image will be affected. Calibrate your monitor and you should get what you see.

I do know how printers make their print thank you very much. Ok, saying red ink was a bad example, but replace red for magenta and the same still applies. If AdobeRGB uses pure magenta ink for magenta parts of an image, then what happens to the ink when the magenta part of an sRGB is printed? Does it use the pure magenta ink? And if so, then surely the gamut is being stretched to map the gamut of the ink/paper. Or does it reduce the amount of magenta ink to keep the gamut from the sRGB true, in which case the image has lot 'potential' colour range? (This is the one I belive to be correct).

You say "Calibrate your monitor and you should get what you see", but there is a lot more to colour management than this. It doesn't take into account paper and ink profiles or the metamerism etc. Im fairly confident with colour management, but I need to know what happens mathematially when you put a low gamut image onto a high gamut output device.

 

[Messiah Khan]

The range of colours isn't stretched to fit the size of the printer's space, they stay the same. In one sense you could say the colours were muted as a result but only relative to the available saturation of the larger space, they haven't really changed - assuming a calibrated screen then the result should match.

If you want to use the full saturation of the printer's colour space then use a larger space for the image during the processing stage. Banding can be an issue with larger spaces because you still have 8bits to represent more colours unless the printer driver fully supports 16bit image data.

The golden rule is to use a colour space smaller than the output device but big enough for the colours in the image.

This is the answer I was looking for. It works as I had expected. Thanks.

 

[EOS_JD]

I do know how printers make their print thank you very much. Ok, saying red ink was a bad example, but replace red for magenta and the same still applies. If AdobeRGB uses pure magenta ink for magenta parts of an image, then what happens to the ink when the magenta part of an sRGB is printed? Does it use the pure magenta ink? And if so, then surely the gamut is being stretched to map the gamut of the ink/paper. Or does it reduce the amount of magenta ink to keep the gamut from the sRGB true, in which case the image has lot 'potential' colour range? (This is the one I belive to be correct).

You say "Calibrate your monitor and you should get what you see", but there is a lot more to colour management than this. It doesn't take into account paper and ink profiles or the metamerism etc. Im fairly confident with colour management, but I need to know what happens mathematially when you put a low gamut image onto a high gamut output device.

Colour management is a very complex beast and maybe I'm not so good at explaining things but the answe above is what I meant I wasn't being cheeky when I said learn how printers print. Sorry if that's how it came across!

JD