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Old Jan 31, 2003, 8:22 PM   #31
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I did read some of the the color space discussion above, but admittly not all of it. With the hours I'm working, time for this type of education is limited. At least I'm working....

Now that my brain isn't dribbling out my ears, I've read it all over again and I think I see. The camera is capturing more than my monitor can display (I live in 32-bit on my new machine.) I don't know how many printers an do it, but none that I'll have in my house, I assume. So more won't help me that much.


Because of the limitations of printers people have at home, a friend who does this as a semi-pro (has a day job, does contract work on the weekend) was saying that he hasn't gone out and bought a colorometer (sp?) to calibrate his monitor. It doesn't have to be perfect because he can eyeball it well enough to be as good as his Epison 2200. Why get it "perfect" on the montior when it can't be perfect on the printer? Improve the weakest link first!
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Old Feb 1, 2003, 12:55 AM   #32
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Eric & Jim

My 2c:
he hasn't gone out and bought a colorometer (sp?) to calibrate his monitor. It doesn't have to be perfect because he can eyeball it well enough to be as good as his Epison 2200. Why get it "perfect" on the montior when it can't be perfect on the printer? Improve the weakest link first!
This works just fine as long as the print is his/or client "standard". However eyeballing the picture to match the print usually results in the wrong color / brightness when this picture is posted on the web, and viewed on another person computer. Are we're all seeing the same color? :? A Spyder colorimeter is usually quite inexpensive (and is always on sale @ dpReview), and I rather create a custom profile for the Epson printer to match the source. BTW this is also preferable when one has several brand of printers! Beside the monitor color ages as it first turn-on or left on for days (The colorvision SW that comes with the Spyder reminds you to recalibrate every two weeks)... and then we have MAC vs PC which have two different gammas! :lol: :lol: :lol:

Inkjets are CMYK devices and have a more limiting gamut than your monitor's RGB gamut. If you use Photoshop you can see that by setting gamut alert on and seeing dark brown on colors of your image that wont print CMYK.
OK, let try to oversimplify this a little bit:

1. For this example let pick AdobeRGB as 4-bit by 3-bit picture mat opening measuring in inches, ie 16x8 inches.
2. An sRGB monitor is also 4-bit by 3-bit picture mat but measured in centimeters, ie 16x8 centimeters.
3. A printer for this example is 3-bit by 4-bit picture mat but measured in centimeters, but rotate 90 degree (to simulate CMYK), ie 8x16 centimeters.
4. For this example let assume the camera CCD is only 4-bit by 3-bit resolution with no unit!

When an image is taken in sRGB, the resulting picture fits the sRGB monitor perfectly, but if this the picture is output to a printer some gamuts are in, but some are also out since the printer mat's shape doesn't exactly align with the sRGB mat. The non-intersecting surface is lost! This is where AdobeRGB comes into play.

The same picture if saved in AdobeRGB format (in the D7hi/D100 etc) still has the same 4-bit by 3-bit resolution (ie no new color is created, resolution is still the same), but is now mapped to a larger(gamut) 16x8 inches area instead of the sRGB's 16x8 centimeters, and will also cover the 8x16 centimeters area of the printer!
Can everyone see this? Now this is where all the extra bits come into play: Imagine instead of measuring in inches (ie 8-bit), one measure the same scale in fraction of inches (ie 16-bit) which help the conversion from one device to another with minimum rounding errors... I know this is an oversimplification(ie I left the camera gamut out), but has everyone got the idea?
Doing this process in sRGB will usually clip something off when the gamut between devices have large offsets (especially when one can't see) :? However for most purposes and home/hobby sRGB is plenty adequate since the inkjet gamut is rather limited as well... but it's good to know and to watch out for as better printers become available! The other dpReview poster said its best:
If you look actual colorspace utilization as Marqulis explains it, sRGB and AdobeRGB are like two armies, each 16 million strong. The difference is that most of the sRGB soldiers are on the front line in the trenches (the part of the CIELab gamut the camera / scene photographed actually record) while many of Adobe's possible color combination are held in reserve in parts of the gamut not typically photographed.
But AdobeRGB is better in general for capture because it is a better fit to the destination CYMK output. But since you usually don't know what you'll use on the web vs printing its best to shoot in AdobeRGB all the time if you are sophisticated enough to convert the files you do use on the web to sRGB...
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