Page 74 - NyghtVision Magazine Volume 3 #4
P. 74
out of the camera is “good enough.” Even in the con- quent articles we will look at related issues. Here, our
trolled environment of the studio, it rarely is, and focus is creating a camera profile.
even then, if all the devices are not calibrated, the Compared to other tools designed for creat-
results will be disappointing. Fourth, just because ing color profiles for the camera, X-Rite has created
we are digital photographers, we are not free from a quick and easy way to make excellent color profiles.
the responsibility for processing our images correct- We use the Color Checker Passport all the time. It
ly. We can't process our images correctly if we don't is a quick and easy way to make sure that when the
manage color. time comes to process the RAW images we will pro-
We want to learn to think about end to end duce images whose colors are accurate and faithful.
color management as essential and central to a digi- The Color Checker Passport is small enough to fit in
tal work flow. End to end color management begins a shirt or pants pocket or in a camera bag. Mine lives
with the camera and ends with image output. Tra- in my camera bag so it is always with me. At the be-
ditionally, color management is done via a special ginning of each shoot and when I change locations or
profile. Called ICC profiles,1 when you calibrate your sets, I photograph the Passport. One photo that can
monitor, or, when you download - or create - paper say precious time attempting to correct all kinds of
specific profiles for your printer, the results of that problems.
calibration process are saved to a device specific pro- The software can be downloaded from X-Rite's
file and then loaded, usually when your computer web site and it available for Mac and Windows. The
boots, into the computer's memory. Even if you have Color Checker Passport software is very easy to use
two of the same monitors, each will have a unique and it produces not an ICC profile but a DNG. DNG
profile. While manufacturers test their monitors be- is an abbreviation for Digital Negative. DNG is an
fore shipping them, they do not calibrate them. The open lossless RAW image format created by Adobe.
same is true for camera and printer manufacturers. Ostensibly created for archiving RAW images, many
Consider this – another lesson learned the cameras support DNG as well as a proprietary RAW
hard way – go the your favorite supplier of ink and format.
over the course of a year purchase the same color Creating a DNG profile is easy - Either click
three times. At the end of the year, print each image on File and then Add Image or drag and drop the im-
once swapping out the ink each time. The results to age you want to profile into the application window.
the trained eye – and sometimes to the untrained eye Note:
– will be different. Very different some times. Every
batch of ink differs from the one before it and the one 1 The Color Checker application does NOT read
to come after. Best to correct variances by creating a
new ICC profile whenever you change ink. In subse- any file format except DNG so, you will need to do
one of two things -
1 According to Wikipedia, "In color manage-
ment, an ICC profile is a set of data that character- a Process your RAW images and output
izes a color input or output device, or a color space,
according to standards promulgated by the Interna- them as a DNG or
tional Color Consortium (ICC). Profiles describe the
color attributes of a particular device or viewing re- b If your camera supports it, change the de-
quirement by defining a mapping between the device
source or target color space and a profile connection fault format from your camera's proprietary format
space (PCS). This PCS is either CIELAB (L*a*b*) or to DNG. The images in this article are from a Ricoh
CIEXYZ. Mappings may be specified using tables, to 645D saved in camera as DNG.
which interpolation is applied, or through a series of
parameters for transformations." 2 The image should include somewhere in the pho-
tograph a Color Checker Passport.
3 The software will automatically try to identify
the Passport. If it can't, you can isolate the passport
manually.
We should also note that there is a size lim-
it on the DNG you import into the application. We
74 | Creating a Camera Color Profile
