Digital Light & Color

A word of caution about the SpyderCheckr. I recently purchased a SpyderCheckr 48 to test and used it to create some profiles. I noticed variations in the curves it produced so I went back and hand-measured all the patches with a spectrophotometer and the values I got were significantly different from those in the reference file. Using my reference values, the curve became smooth, indicating that the brightness levels of the gray patches were off compared to values in the reference file they supply (and likely the color patches as well). This suggests one of two things is happening, neither of which is good:

1) There are variations from target to target due to inconsistent manufacturing

or

2) The supplied reference file is inaccurate

Did you update the values in PWP8 to reflect your measurments...sounds like you should ...I would measure mine if I had the hardware...that is interesting.....

The next release includes a second set of reference files since I can't tell if the problem is the old reference file or my target.

I think I may have had up to 3 sets of values...there was the old ones from 2011 that came with ArgyllCMS, I had the pdf from Datacolor, I also had data from dcamprof or rather its paid version Lumariver that contained also wavelengths.

This problems I was seeing were with the SpyderCheckr 48 -- the brightness values of the gray patches on the left hand side were inconsistent with the gray patches on the right hand side. The extra gray patches were presumably designed to provide additional points on the tone reproduction curve. FYI, here are the reference values I measured for the SpyderCheckr 24:

SpyderCheckr24
LGOROWLENGTH 12
ORIGINATOR "SpyderCheckr 24"
MANUFACTURER "Datacolor"

11/6/2020 # Time: 21:45

NUMBER_OF_FIELDS 4
BEGIN_DATA_FORMAT
SAMPLE_NAME Lab_L Lab_a Lab_b
END_DATA_FORMAT
NUMBER_OF_SETS 24
BEGIN_DATA
1E 96.04 2.16 2.60
2E 80.44 1.17 2.05
3E 65.52 0.69 1.86
4E 49.62 0.58 1.56
5E 33.55 0.35 1.40
6E 16.91 1.43 -0.81
1F 47.12 -32.52 -28.75
2F 50.49 53.45 -13.55
3F 83.61 3.36 87.02
4F 41.05 60.75 31.17
5F 54.14 -40.76 34.75
6F 24.75 13.78 -49.48
1G 60.94 38.21 61.31
2G 37.80 7.30 -43.04
3G 49.81 48.50 15.76
4G 28.88 19.36 -24.48
5G 72.45 -23.57 60.47
6G 71.65 23.74 72.28
1H 70.19 -31.85 1.98
2H 54.38 8.84 -25.71
3H 42.03 -15.78 22.93
4H 48.82 -5.11 -23.08
5H 65.10 18.14 18.68
6H 36.13 14.15 15.78
END_DATA

Thanks for sharing I'll take a look at how those compare.....thanks for the update....

Jonathan, what device do you use to measure/calibrate with....considering maybe purchasing something to calibrate my monitor...

I have several monitor calibrators. If you have a good monitor, it is likely that calibrating will make very little difference -- at the end of the process the calibration software shows you the before and after calibration of the same test image and I never see much of a difference.

I have the following two recent model monitor calibrators:

X-Rite i1Display Pro
Datacolor SpyderXPro

They are quite similar and both do the job.

If you want to measure color targets for creating camera, scanner or printer profiles you need a spectrophotometer which is much more powerful and more expensive than the colorimeters used in monitor calibrators -- I have an older i1Pro:

https://www.bhphotovideo.com/c/product/ ... ml/reviews

There are some available for much less on eBay, but you may have trouble getting the companion software i1Profiler to work.

Thanks for all the info...I will check it out...I appreciate your insight....

Jonathan wrote: I have several monitor calibrators. If you have a good monitor, it is likely that calibrating will make very little difference -- at the end of the process the calibration software shows you the before and after calibration of the same test image and I never see much of a difference.

Thanks for that, Jonathan. For years I had a calibration system permanently connected to my 11 year old monitor (it reads ambient light and automatically adjusts monitor brightness for changing conditions). At least once or twice a month it prompted me to go through the calibration process and each time there was a noticeable difference between the before and after colors.

Last year I finally purchased a new and larger fairly high end monitor (long overdue). For several months every time I checked there was virtually no difference between the before and after. So I haven't calibrated for months. It appears that newer and/or high end monitors are pretty spot on out of the box and hold that setting long term.