Independent Color Standard for Monitor Calibration

[dppollet]

Although I frequently calibrate my monitor with an Xrite i1 Display Pro, I recently received some prints from a photo lab that had substantial color shifts from what I had observed on my monitor.  Note that prior to submitting my files to the photo lab, I always convert the print files from my working color space (Pro Photo RGB) to the lab’s Noritsu 3411 calibrated color profile.  

After rechecking my monitor calibration (still calibrated) and noting that the lab’s printer had been calibrated within the month, I am thus at a loss as to how to determine which device is inaccurately calibrated:  my monitor or the lab’s printer.  

I also discussed the problem with Xrite’s technical support.  The only way to check the accuracy of my calibrator would be to send it back to them.  They did not know of any secondary standard that I might use to check it.  

However, they did provide me with two data files of test images.  These files have been apparently verified to be “colorimetrically accurate” in that the color values of the files have been verified to correspond to the color standard used to generate the profile.  Unfortunately, hard copies of the files are not available.  That is, a color accurate hard copy would provide me with the means to use them as a secondary or working standard that I could judge either the monitor’s color performance or that of the lab’s printer.  

Nevertheless, I plan on printing the unedited files on the lab’s printer.  My only change to the file would be to convert the file’s embedded profile (Adobe RGB) to the lab printer’s calibrated profile.  If there are substantial color shifts then this approach may allow me to determine if the color inaccuracy lies with the lab’s printer.  However, this is potentially in doubt because I do not have a color accurate print to compare the lab print to.  That is, if the shifts are not objectionable, then I don’t have any means to determine which is in error.  

Hopefully, my somewhat long winded description suffices to illustrate the root of the problem:  the absence of a hard copy working standard that I can use to independently assess my monitor calibration.  

Thus, does anyone know where one might obtain both color accurate test image files and color accurate hard copies of these same files? I realize that this is not an ideal approach but it is better than what I have now.  

[Frank Kolwicz]

A google search for "Certified Color Standards" turns up lots of possibilities as color matching is important for many industries and scientific uses. At one time I had a set of color chips for shades of warm gray, but I can't find it, so I can't send you the producer's name.

There are chips, like for house paint, that fade eventually and there are fired ceramic plates for the longest lasting standards. The color checker cards that you see in many camera and lens reviews are available through photo dealers. There are some color sets that provide RGB and/or CMYK values for each color too.

[Bob Atkins]

The Macbeth color chart is often used as the "gold standard" hard copy for color calibration and is available from many sources, including Xrite as their Original ColorChecker Card. If they don't know how to get you properly calibrated, I don't really know who can. Since they sell the chart and seem to be willing to provide you with color calibrated files, they should be able to help.

As you may be able to tell, I'm no color calibration expert, but the guys at Xrite should be!

Have you tried a different printer? If both produce prints with the same color problem, it's probably your fault. If they come back different from each other, it's likely the printer's fault. Who knows how well they calibrate their printers?

[dppollet]

Update: 

As I indicated in my earlier post, I converted the test image’s native ICC profile (Adobe RGB) to the lab’s Noritsu 3411 printer’s calibrated profile and submitted two files for printing.  One print was printed on luster paper using the profile for luster paper while the second print was printed on gloss paper using the profile for gloss paper. 

Evaluating the differences between the prints, I found obvious color shifts between the gloss and luster prints.  In my opinion, these shifts were more than what could be attributed to the differences between gloss and luster paper. 

I also used a recently acquired Xrite ColorChecker Passport to further evaluate both the monitor calibration and the prints of the test images.  In regard to the monitor, I did not find any significant color shifts between the monitor and the ColorChecker Passport albeit that this comparison is necessarily only approximate.  That is, the comparison is only roughly approximate both because of the differences in mediums, and because the comparison is also sensitive to the lighting in the comparative viewing. 

In regard to the comparison between the ColorChecker Passport and the lab prints of the test images, the colors in both the luster and gloss prints were significantly desaturated from the targets in the ColorChecker Passport.  There were also perceptible color shifts between the prints and the targets. 

As a result of these differences, it was apparent that the color profiles (gloss and luster) for the Noritsu 3411 were out of calibration. 

That said, I would like to add that either the ColorChecker Passport or hard copies of the Gretag Macbeth color pattern can serve as a secondary color standard.  However, it should be recognized that such a standard is only approximate because of the effects of lighting conditions and differences in mediums.