X-Rite Passport Inaccuracies
X-Rite Passport Inaccuracies
- Subject: X-Rite Passport Inaccuracies
- From: Justin Krug <email@hidden>
- Date: Fri, 20 Sep 2013 09:18:06 -0700
- Importance: Normal
I was directed here by a helpful photographer whom I contacted regarding
my issues with the X-rite Passport. My primary purpose for using it is
to get accurate and consistent colors across different ambient and
artificial light sources for architectural photography. For example, I want the colors in the photo taken with ambient/artificial mixed light to match with those taken under CFL's at night. Also, I wanted
to use it to match color between cameras. On both counts, it has
failed, and when I subjected it to a test using the reference values
available on X-rite's website, it did not perform well. I would like to
get some feedback from experienced members here regarding my findings
and the response I received from X-rite after sending them details of my
testing.
Here is an outline of my test:
1) I took the photo
of the X-rite Passport under overcast daylight (no artificial light)
with two cameras, the Canon 5d and Canon 60d.
2) Then I created custom profiles from each photo using the X-rite Passport software.
3) Next, I applied the custom profile to each photo of the Passport
4) White balance was corrected in ACR by clicking the WB on the square two over from black (#22)
5)
Both photos were loaded into Photoshop and color sampler points were
applied to the blue, green, red, and yellow squares (#'s 13,14,15,16)
6) The image was converted to Lab color and the a and b values were compared against the reference values on X-rite's website.
7) The same process was repeated for the photo from each camera using the Adobe Standard profile
What
I discovered was that the color was just as accurate if not more
accurate in the Adobe Standard profile. Also, the colors did not match
between the Canon 60d and 5d after applying the X-rite profiles.
A couple sample points from the Canon 5d (again, a,b values):
Daylight
overcast test-- X-rite: red a,b= 69,41; Adobe Std: red a,b= 61,37;
Reference (rounded to nearest whole number): red a,b=53,28.
X-rite: green a,b=-51,39; Adobe Std: green a,b=-47,36 Reference: green a,b= -38,31
I
did the same test under artificial light (CFL I think) and the results
were a little closer between the Adobe Standard and the X-rite, but for
$100 and promises of accurate color, I was very disappointed.
After
contacting X-rite, and sending over my findings and photos, I waited
over a month to hear back, after their engineers were going to review my
results. The response I received was surprising. X-rite said "To make
a long story short, your standards for performance and data analysis
would not be well suited to use ColorChecker Passport and its DNG
profiles." And also "ColorChecker Passport software was designed to be a
simple camera profiling solution for casual and non-professional
photographers..." The recommendation was that I use an ICC profile as
opposed to a DNG profile. They also offered me a refund on the
Passport.
What do you think of my test and X-rite's response?
Have you conducted your own objective testing? I don't need perfect
color, but I do want consistent and accurate looking color. Thanks in
advance.
-Justin Krug
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Colorsync-users mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden