Color space and online printing

[93octane]

I have read both about sRGB and aRGB seems Adobe RGB is better because of more colors. I usually print all my pictures at ofoto.com or samsclub.com. How do I know what color space they are using? I was also reading on my 10D manual that if you shoot with any parameter other then Adobe RGB everything else is sRGB. I can shoot raw and then make the converstion to either but what is recommend since I never print at home???

[scottbergerphoto]

Most onlne printers require sRGB. I suggest :
1. Shoot Raw
2. Convert to 16bit tiff Adobe RGB
3. Edit your shots.
4. Image>Mode>Convert to Profile>sRGB
5. Convert to jpeg.

[tim]

Every color space conversion loses information. I'd suggest that if your target color space is sRgb that you work in that space for the whole time you're processing the image.

http://www.shootsmarter.com/infocenter/wc025.html

[Nightcrawler]

Every color space conversion loses information. I'd suggest that if your target color space is sRgb that you work in that space for the whole time you're processing the image.

http://www.shootsmarter.com/infocenter/wc025.html

I agree. When you work in aRGB and convert to sRGB you not only lose color information, but you also could possibly clip individual channels if you are not careful. It is a lot easier to deal with colors when you don't have to change spaces.

[Sathi]

If most monitors cannot display the entire gamut of aRGB, then how are you supposed to know what you are getting when you edit in that colour space? I have read that some high end inkjet printers can print into the range that aRGB offers...but still how are you going to know what your print is going to look like if your monitor cannot display it?

[UncleDoug]

Most onlne printers require sRGB. I suggest :
1. Shoot Raw
2. Convert to 16bit tiff Adobe RGB
3. Edit your shots.
4. Image>Mode>Convert to Profile>sRGB
5. Convert to jpeg.

Dont' forget to switch back to 8bit before you send the images out. All the printers out there are 8bit. Printing a 16bit image comes out like an acid-test poster.




Every color space conversion loses information. I'd suggest that if your target color space is sRgb that you work in that space for the whole time you're processing the image.

Tim, you are right about information loss in general, but not in this case.
Adobe RGB completely encompasses sRGB, nothing is clipped so nothing is lost. So when you convert from AdobeRGB to sRGB info is compressed but not clipped or lost. If you are converting using perceptual rendering intent, all will be fine.



If most monitors cannot display the entire gamut of aRGB, then how are you supposed to know what you are getting when you edit in that colour space? I have read that some high end inkjet printers can print into the range that aRGB offers...but still how are you going to know what your print is going to look like if your monitor cannot display it?

It is the same concept as: "why work in sRGB since the printer I send my images to can not reproduce the full gamut of sRGB."
If you are following an ICC compliant work-flow, delve into the soft-proofing feature of Photoshop.


Your monitor is nothing more than a yard-stick, just as the RGB/CMYK numbers in the Photoshop info palette is. If you fly only visually, when you enter a cloud, you are screwed if you can not fly by the numbers as well. :D

[Scottes]

Every color space conversion loses information.
This is true. But it's pretty negligible if you only convert once. So if you shoot and process in AdobeRGB and then - at the end - convert to sRGB you're only converting once.

Well, twice, really. Once from the "native colorspace" of the sensor, then to AdobeRGB (this conversion is done by the camera), then finally to sRGB to send to the printer. (And you should save a copy of that final image in AdobeRGB of course.)

I'd suggest that if your target color space is sRgb that you work in that space for the whole time you're processing the image.
This I most definitely do not agree with.

(I have to admit that I didn't read the article since I don't have an account and don't want one, but I simply can not agree with this sentence or thought or strategy.)

Work (ie; process) in the largest possible space to retain the most information. Save a copy, then convert down to the final image for viewing/printing/etc.

Staying in sRGB just does not make sense, since it's possible to perform post-processing steps that would result in colors that do not fit within the smaller color space of sRGB. These colors then get clipped, or "blown" in photographer-speak. Another post-processing step might have pulled those colors back into the sRGB space, but it's too late since they're already blown. You can not get details (or colors) back after they're been blown out, or pushed outside the boundaries of a color space.

Staying in sRGB during the entire post-processing procedure is like staying 8-bit the whole time. It does not make sense to work in a confined area when such a confined area may cause loss of details and/or color.

Work in the largest space(s) possible, and finally - and only finally - convert ONCE to the destination.


Here's an article from Luminous Landscapes about ProPhotoRGB, a color space that's even larger than Adobe RGB. http://www.luminous-landscape.com/tutorials/prophoto-rgb.shtml

[robertwgross]

If you fly only visually, when you enter a cloud, you are screwed if you can not fly by the numbers as well. :D

The trouble here is that we are flying in the clouds, and the clouds have rocks in them.

I think it is good that _somebody_ understands color space.

Every time I need color space inspiration, I wander over to Calypso Imaging and look at their super large photos on the wall.

---Bob Gross---

[UncleDoug]

The trouble here is that we are flying in the clouds, and the clouds have rocks in them.

I think it is good that _somebody_ understands color space.

Every time I need color space inspiration, I wander over to Calypso Imaging and look at their super large photos on the wall.

---Bob Gross---

Thanks Bob.
Yeah, those rocks can bend a propellor or two! :D

The LuminousLandscpe article is a good one.
ProPhoto RGB is a good tool.
But the last paragraph of the article, I feel, needs to be emphasized at the beginning of the article.

I quote the article;
"But, on the other hand, an image file in a wide space such as ProPhoto RGB needs to be kept in a cage, so that it doesn't accidentally get into the outside world. Anyone receiving a copy of such a file who doesn't know what they have, and who doesn't function in a properly colour managed workflow, or who presumes that the file is sRGB, can inadvertently use it to produce some really horrid results."
end quote.

It is an unwieldly beast that can come back and bite you in the south end if you are headed north. :)

[scottbergerphoto]

Dont' forget to switch back to 8bit before you send the images out. All the printers out there are 8bit. Printing a 16bit image comes out like an acid-test poster.

When you convert to jpeg using Save For Web, it automatically changes your file to 8 bit from 16 bit.

[Scottes]

When you convert to jpeg using Save For Web, it automatically changes your file to 8 bit from 16 bit.
Though it won't really hurt, Save For Web is not ideal for files going to the printer. It takes more time (yes, I'm impatient) and it's easy to get a file that's too large for Save For Web. But Save For Web doesn't get you anything. Just Save As... and choose JPG, Quality 12. I uncheck the Preview box as soon as possible so it doesn't spend time trying to build a preview. If you're uploading to the printingcompany you could choose Quality 10 to save a little time for a (usually) tiny loss of quality.

Again, Save for Web won't hurt, but it's not necessary for files getting printed.

[UncleDoug]

When you convert to jpeg using Save For Web, it automatically changes your file to 8 bit from 16 bit.

Ah! Nice to know.

I use ImageReady and a script for processing images to the web instead of PS Save for web.

Thanks for the enlightenment.

[scottbergerphoto]

Though it won't really hurt, Save For Web is not ideal for files going to the printer. It takes more time (yes, I'm impatient) and it's easy to get a file that's too large for Save For Web. But Save For Web doesn't get you anything. Just Save As... and choose JPG, Quality 12. I uncheck the Preview box as soon as possible so it doesn't spend time trying to build a preview. If you're uploading to the printingcompany you could choose Quality 10 to save a little time for a (usually) tiny loss of quality.

Again, Save for Web won't hurt, but it's not necessary for files getting printed.
Good to know. Thanks.