Converting Adobe RGB to sRGB

[Shac]

Hi - interested in your experiences when converting to sRGB for printing.
When I've used Camera Raw - the on-screen image doesn't change in its looks color-wise, but when I convert using "assign profile" in Photoshop, you see the image "dull" down.
Which should I be using?
Thanks in advance
David

 

[fbf]

Edit-> convert to profile
do not use assign profile.
The color would change a little bit especially if you print a lot so color profile calibration and proof are crucial.

 

[Shac]

Thanks - I'll give it a try. Still curious about the Camera Raw conversion though

 

[RichC]

Assigning a profile is not converting the profile embedded in an image.

An image coming from a raw converter will have an embedded profile, usually sRGB or Adobe RGB, depending on the options you selected in the raw converter. Let's say, for the sake of argument, the embedded profile in the image from the raw converter is the Adobe RGB colour space.

If you assign a profile, let's say sRGB, to the aforementioned image, you end up with a file that uses the Adobe RGB colour space but which is identified by software like Photoshop as an sRGB image. In other words, you have a mismatch between the colours actually in the image (Adobe RGB) and the instructions on how to display those colours (sRGB).

There are only two instances when you should assign a profile, both uncommon: (1) when a profile is missing (e.g. most images without profiles are generally sRGB - but you might want to assign the sRGB profile so that any colour-managed program will know it's an sRGB image); (2) when a file appears to have a wrong file (like the aforementioned Adobe RGB image with an sRGB identifier - which now needs the Adobe RGB profile assigned, to replace the wrong sRGB one with which it's flagged).

As fbf says, if you want to change the profile in an image, what you should be doing is converting the profile, using Photoshop's "Convert to profile" function. This both attaches the new profile and converts the image colours to the new profile.

When you convert from the Adobe RGB colour space to the sRGB colour space, you won't usually notice much, if any, change, as most colours are unaffected.

The Adobe RGB is larger than the sRGB colour space - in particular, it contains more bright greens and blues: so, if your Adobe RGB image has a lot of turquoise, say, you will see more of change when you convert it to sRGB, because these colours don't exist in the sRGB colour space and must therefore be approximated colours that do exist.

 

[Finder]

I would not use sRGB for printing as it is a monitor color space. Leave your images as Adobe RGB.

When you assign a color profile you are simply telling the software that the RGB coordinates should be sRGB without converting them. Since Adobe RGB has a larger gamut, assigning an sRGB would dull your image. Converting a profile is different as the RGB values are converted to the new color space which should preserve the colors as long as they fit the space.

To step back a bit, specific RGB values do not denote a specific color until they are placed in a color space. Since RGB are color coordinates, what color they appear to be depends on space they belong to. It is just like a map or GPS, the coordinates only work on the projection/space they belong to. To go from one space to another you need to adjust the coordinate values.

 

[RichC]

I would not use sRGB for printing

And I'll second that. The colour space illustration linked to in my post shows an example matt paper colour space (gloss paper would be a bit larger). As you can see, it's larger than sRGB (in some places), so you are potentially reducing the colour range in your print (in practice, it makes little difference for most images - but why throw away information and give yourself extra work by converting Adobe RGB to sRGB?).

As Finder says, you usually only need to convert to sRGB if the images are to be viewed on-screen (sent to friends by email, put on a website, etc.).

 

[Shac]

RichC/Finder - thank you both - very useful and informative. One of the reasons for me converting to sRGB is for the printer of a local outlet. Their machine is set up for thios colour space - probably b/c most people using their service shoot in sRGB. I know if I do not convert and use their printing service - the resulting images are flat.

I'm in the process of replacing my old Epson with something newer - just not sure yet which model - probably the one that is best for B&W

Again thank you all for your help
David

PS RichC the link seems to be broken

 

[charjohncarter]

I would not use sRGB for printing as it is a monitor color space. Leave your images as Adobe RGB.

When you assign a color profile you are simply telling the software that the RGB coordinates should be sRGB without converting them. Since Adobe RGB has a larger gamut, assigning an sRGB would dull your image. Converting a profile is different as the RGB values are converted to the new color space which should preserve the colors as long as they fit the space.

To step back a bit, specific RGB values do not denote a specific color until they are placed in a color space. Since RGB are color coordinates, what color they appear to be depends on space they belong to. It is just like a map or GPS, the coordinates only work on the projection/space they belong to. To go from one space to another you need to adjust the coordinate values.

What if you send them over the Internet or take the disc to Costco for prints? I assume your answer would be the same, but Costco uses wet printing. Is this going to be different electronically; scrambling and jamming the file into your printer? Thanks for the answers/responses above.

 

[Finder]

What if you send them over the Internet or take the disc to Costco for prints? I assume your answer would be the same, but Costco uses wet printing. Is this going to be different electronically; scrambling and jamming the file into your printer? Thanks for the answers/responses above.

The printer should read the file color space and then convert it to a post script for the printer color space. BTW, printer color spaces are always a CMYK profile. The purpose of an image color space is to define the color within the image so then an output device can then deal with that file to reproduce it. The profile is simply a tag like exif data. That should follow the file no matter how you send it.

Does that answer your question?

 

[Shac]

Finder - intersting - b/c when I sent an image to the printer I use in Adobe RGB the print came back dull, but the same pri9nt converted to sRGB was closer to the on screen view (I use a Spyder 3 for monitor calibration)
I'll keep everyone's advice in mind and do some experimenting.
Again thank you all for your help
David

 

[Finder]

David, depending on the printer driver, you may need to go in and set the profiles for the image, printer, and paper. I believe the default for Photoshop when Photoshop manages color is Working sRGB for the printer. Printers do not like that. Our students always have a problems with this. And just to make it easier, printer drivers for a specific printer and from a specific manufacturer are different in Windows and Mac operating systems. If your print is coming out significantly different from your monitor image (assuming the monitor is calibrated), then it usually means a profile mismatch.

 

[Shac]

Finder - thanks - do you set these profiles in "Color Settings" - or?

 

[Finder]

Not knowing your driver, it would be hard to say. It could be "color settings, "color management," "CM," and a host of other stuff. Sometimes it is hiding in an advanced menu.

 

[Shac]

Finder - I was refrring to color settings in photoshop - this is the only pgm I use for images

 

[charjohncarter]

Finder - intersting - b/c when I sent an image to the printer I use in Adobe RGB the print came back dull, but the same pri9nt converted to sRGB was closer to the on screen view (I use a Spyder 3 for monitor calibration)
I'll keep everyone's advice in mind and do some experimenting.
Again thank you all for your help
David

Well, that has happened to me when I send over the Internet to Costco (not all the time) but if I take the file from my computer to the Costco store and do it on the kiosk computers it is more like my screen. This is especially bad if I forget to convert to gray scale. I just use only AdobeRGB.

 

[Finder]

Finder - I was refrring to color settings in photoshop - this is the only pgm I use for images

Windows or Mac? Which is managing colors, Photoshop of the printer? And my last question is the wild card: which printer?

 

[Disaster_Area]

The problem is that short of professional printing labs 99% of walmart/costco/local photo place or online print ordering don't handle the Adobe RGB space properly... check if the place you're getting the prints done will handle Adobe RGB... otherwise use sRGB.

 

[Shac]

Finder - Windows, I thought Photoshop was managing it, and I'll find out what's the printer

Disaster Area. I was told the lab used sRGB and that's what I try to give them

 

[charjohncarter]

The problem is that short of professional printing labs 99% of walmart/costco/local photo place or online print ordering don't handle the Adobe RGB space properly... check if the place you're getting the prints done will handle Adobe RGB... otherwise use sRGB.

Thanks, I'm not sure if they will know, but I'm going today so I'll ask.

 

[Finder]

Finder - Windows, I thought Photoshop was managing it, and I'll find out what's the printer

Disaster Area. I was told the lab used sRGB and that's what I try to give them

If Photoshop is managing color, under that you need to specify the printer/paper profile--the default is usually Working RGB. You also need to turn off color management in your printer driver--check the help section of your driver.