der CM takes another poke at Color Calibration - your opinions are invited

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Thought I'd share this with you - this was written by me in response to the question "What happens when you take a picture, edit it in Elements or Photoshop, and send it to CostCo for printing?".  I hope you take this as intended, in fun, and don't hesitate to chime in with your own opinions.  Diversity of thought will be welcomed!

Here's my take on how colors are converted, from camera click to display, to final printout at CostCo :-).

1) In the camera
a) Each individual pixel of the image is exposed to one of three colors - generally red, green, or blue.
b) The camera calculates the brightness of each pixel by a constant based on  the color of the pixel.
c) The color of each pixel is determined by a weighted average of the brightness of the group of surrounding pixels, and the color setting (daylight, incandescent, etc) of the camera.  Some cameras also allow selection of Color Space - sRGB, Adobe RGB, and sometimes others.  The profile is analogous to a tag on a text file specifying the language the text is in: Italian, Spanish, English etc.
d) the camera may or may not embed or otherwise tag the image with a profile.

Now we have an RGB value for each pixel in the camera.

2) In Photoshop Elements
a) Loads the image into memory, and uses the system's display profile to convert the image for display purposes.  This is where screen calibration has its main effect.
b) After editing, the image is saved back, normally with an sRGB or Adobe RGB profile embedded in it.

3) at CostCo
a) By default, the image is examined to determine the embedded profile.  If there is no profile, sRGB is assumed. 
b) The image is converted to a special color space for the specific printer being used, using a profile similar to the ones on file at drycreekphoto.com
c) The image is sent to a Fuji Frontier printer.

Additional thoughts and observations.

Yes, it should be simpler, and it is if you use common sense, and don't go traipsing off into color la la land, viz:

Drycreekphoto.com documents how you can work directly in the color space of the printer, by using one of individual per-system color profiles from its web page.  This is a tricky business, because you do not want the operator, in this case, to treat the image as an sRGB image and give you screwy colors.  Why would you want to risk having this happen?  The answer lies in some of the juicy colors, particularly bright, saturated yellows, magentas, and cyans, that are not possible to access in sRGB.  And, for some unfathomable reason, it is just plain cool to do so. You are like Promethius, borne heavenward on wings of wax and feathers, tweaking the nose of the color god himself, and your reward is some kind or other of incredible colors.

The downside?  Well, we all should know what happened to Promethius - your colors could, and probably will, melt, crash, and burn.  In trying to fix this, you may wind up spending more on color calibration gadgets than you will ever spend on the prints themselves, and still that wil o the wisp - perfect color calibration eludes you (insert deep echoing Jovian RITCL (rolling in the clouds, laughing) here, and the two words "viewer metamerism").  No joke, though.  A whole industry is built on this feckless persuit.

SRGB is the color equivalent of the Garden of Eden.  It's a nice playpen with plenty of everything we mere mortals, if we are wise, will need.  Venture outside at your peril, because once you taste the fruit of the knowledge of good and evil color gamuts, you may be banished by the angel Gabriel, doomed ever to comb the earth for the latest and greatest color calibration paraphernalia, leaving a trail of Colortron II, i1 Displays, Spider 1's Spider 2's, and other obsolete equipment in your wake, yet your desire shall remain the quest for perfect color match, from camera to print. (insert old Testament style, Yaweh-an laughter this time).

The lesson from all of this?  Walk away confident that your camera, printer, and monitor, were all calibrated, at the factory, with devices that cost as much as your car, or even your house.  Give the gods their due, and do not tweak their beards: use sRGB in good health, and leave the color gadgeteering to those, like myself, who really enjoy color puzzles, and have more money than sense.  With luck, a few of the better ideas will prevail, and be silently incorporated into future products, making your life easier.

And trust your eyes.  Look, remember the old saying that seeing is believing?  It's true.  If your monitor is too dark, crank up the brightness.  If it is too green, tweak the RGB controls until it is not.  If your prints are too dark, and you don't want to change your monitor, then lighten them a bit before sending them to be printed.

My holiday wish for you is this: use common sense, enhance your own ability to see colors, get excellent images doing so, and save a ton of money on gadgets.

[RonBoyd]

Hear! Hear!

Or simply purchase a good Photo Printer (Epson R3000 or SP3880?) and eliminate Costco from the formula.

[leeharper_admin]

Thanks for the link to Drycreekphoto.com Mike - it's a great resource.

Something that you wrote in your post is - I think - a little misleading (unless I'm misinterpreting what you're suggesting) is that it is possible (albeit more complicated) to get good results working 'directly in the color space of the printer.' Drycreekphoto.com advise against this, saying 'Editing color spaces are designed for editing. Printer color spaces are not.'

Drycreekphoto discuss optimizing images by soft-proofing in the printer color space, but not editing the file from beginning to end in the printer color space - which is I'm sure not what you meant to suggest, but your comment does read that way (to me). I've always had the impression that printer profiles are perceptually non-uniform (so for example a 2-point move to the Red channel at one point on the curve will not look like a 2-point move elsewhere on the curve - one of the moves will look stronger than the other); whereas editing spaces are designed to be perceptually uniform. Therefore the advice is generally to edit in an editing color space, and then (if you really care about your prints) to soft-proof using the printer color space.

I would just add that if you really care about your prints you would probably be disinclined to use a service like CostCo anyway :)

What are your thoughts about this?

Lee.

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Absolutely correct, Lee.  Working in the printer color space has a number of disadvantages in addition to the ones you describe.  I also said Promethius when I meant Icarus ....

[leeharper_admin]

You're piqued my interest now Mike - what other disadvantages are there?

Lee.