The new Digital Target - 3
now 570 color patches for more precise profiles !
new: Comparing the Adobe Camera Raw / DxO Optics Pro renderings
Quick links:
Presentation of the test chart
Photographing the test chart
Special case of RAW format shots
Configuration of Camera RAW
Configuration of DxO Optics Pro
v4 & v5.1
Configuration of Hasselblad Flexcolor
Configuration of Capture One
Price of test chart
Use of profiles
Demo images for application of profiles
The Digital Target - 3 test chart was tested by Gilbert Volker you can read his comments on his exhaustive web site ( french ): http://www.volkergilbertphoto.com/digitaltarget.html
The CCD or CMOS sensors
used in digital cameras pose some problems with regard to colorimetry: nonlinear
drift of colors (not easily corrected with curves), high lights without details
and imperfect white balance. With the adequate calibration and selection of the
proper settings when creating the profiles, you can get close to a
“traditional” rendering.
Also, just like
with printers, each sensor has a unique behavior: for the same camera model,
each individual unit is unique and features minor but noticeable differences for
the demanding photographer! This is why it can be difficult to successfully use
the ICC profiles (when available) created for a camera which is not yours (and
thus behaves differently).
The procedure is simple: you photograph a test chart featuring 570 referenced colors (36 levels of grays and 534 colors) with optimization of the common hues (skies, flesh tones, green vegetation, saturated colors) and of those hues which are typically a problem for digital sensors. The image file is then processed by an ICC profile creation software which compares the test chart reference file with the colors in the file from the camera. After comparison, you obtain a colorimetric correction ICC profile which you can use in any ICC compatible application (such as Photoshop) to bring new life to your images (even the ones you shot before calibration, by just applying the profile).The profiles obtained correct the chromaticness (colors) but also the saturation and contrast of your images.
Test chart dimensions: 20 x 30 cm – The chart features 570 color patches
on a mat backing. Each test chart is measured with a spectrophotometer and comes complete
with its numbered reference file (2 files supplied: 1 LAB-mode file, 1 SPECTRAL-mode
file).
These reference files can be used by any compatible ICC profile creation
software.
Image examples of the application of ICC profiles created with the Digital Target - 3
Move the mouse over the image to see the correction of
profiles generated for an EOS-1Ds
with RAW shooting and DxO Optics Pro development
with / without CMP ICC profiles
-- There is no special effect, only the action of the profiles --
Photographing the Digital Target - 3
The shooting conditions and the use of specific settings are extremely important in order to obtain quality ICC profiles. The following requirements are all essential to obtain a usable shot: proper exposure, uniform lighting and selection of a shooting angle without stray light.
- Choice of light,
location and framing
To obtain a good quality and uniform lighting, it’s easier to shoot outdoors ( natural
light or overcast sky ), avoid shadows when sunny in a clear location and avoid
colored walls nearby. The ideal is to shoot indoors with
2 light sources ( daylight type or 45° flash light ) lighting the
test chart. Center the test chart in the viewfinder with a long focal length (if you are
using a zoom) to avoid vignetting in the corners and use a frame wide enough so
that the test chart fills half the frame.
I insist on the fact that the test chart should be shot with a flash to obtain optimum quality of the ICC profiles.
If the white balance of a
camera aligns the RGB levels such that the white is white,
the grays are seldom
properly calibrated.
Move the mouse over the image to see the correction of profiles on the range of
grays.
- Exposure
For exposure checking, it is easier to use the LAB mode in the Photoshop
information window ( right click on the eyedropper in the window and select
LAB value display and to consider only the L value (luminance) in
the information window the RGB values are not reliable in our situation since
the 3 values are never identical.
Shoot in the manual exposure mode when you open the test chart image in Photoshop, patch O-12 should be between LAB levels 51 and 52 (component L). Patch O-12 should not be below 51 or above 52.
You can take several shots after changing the speed and select
the shot best matching the above values ( L52 for patch O-12 ). ATTENTION:
If the values are not right, do not edit your files with Photoshop !!
It is also very important to make sure that the test chart is uniformly lit:
the four corners of the black area around the test chart must be at
the same level when you check with the eyedropper tool in Photoshop. If one
corner is lighter, it means that there is some stray light... and you need to
reshoot your pictures!
Special case of RAW
files – Shooting the Digital Target - 3
RAW file
development softwares ( such as Adobe Camera Raw or usually include
internal corrections for each camera, but you still need to calibrate the files
developed from these softwares -- the improvement obtained by calibration is
quite significant!
The procedure to follow depends on the software. With Camera Raw and the original profiles are integrated into the software, calibration is being performed upstream in Photoshop.
With DxO Optics Pro v4 and v5.1, the procedure is simpler since it was designed by the software developer ( see this page for more information ). To develop the test chart, just click on the appropriate button and then select your profiles in the list ( after creation of the profiles ). Integration of this procedure and of the profiles into the workflow yields spectacular results ( see this page for a sample image ) and allows further optimization of the interpretation and use of your camera ( see chart below ).
Comparison of the gamut of an
EOS-1Ds calibrated
Adobe Camera Raw (white curve)
DxO Optics Pro (red curve
Price of the Digital Target - 3
The calibration
charts specially designed for digital cameras are not legion and are still
expensive. Each of the test charts I offer is measured individually for better
results and the improvement is quite noticeable. The DigitaL TargeT - 3
test chart is affordable: the pack includes one test chart and the reference files ( LAB and spectral data ), all for the price of 92 Euro ( including worldwide shipping )
I offer for free the creation of a pack of 5 ICC profiles ( ekta, negative and copy work ) for the purchase of one test chart. Other profiles for other
cameras can be created for the price of 48.50 Euro per pack of 5 profiles.
You can pay by credit card through (secure payment) for all international orders:
Click below to purchase the Digital Target - 3 calibration test chart
Creation of ICC profiles from
your photographs of the Digital Targel - 3
Many settings can
be used to create ICC profiles for digital cameras the profile quality depends
on the software used, and some experience is necessary to obtain quicker
results.
This is why I propose to create profiles for your cameras ( based on your
photographs of the Digital Target - 3 test chart ). These profiles are
generated with Profile Maker PRO from Gretag Macbeth and are available in
5 profiles packs:
- 2 profiles with
an Ekta type rendering (high-contrast saturated reversal film): one
normal profile and one which corrects your camera’s white balance problems.
- 2 profiles with a Soft type rendering (soft negative film), one
normal profile and one which corrects your camera’s white balance problems.
- 1 profile with no special rendering, for copy work.
The price of the digital cameral profile pack is 48.50 Euro. ( The first profile pack is free with the purchase of a test chart )
You can pay by credit card through (secure payment)
Image samples of profiles created with the Digital Target - 3
Correcting your images with the ICC profiles obtained is easy: open your images in Photoshop and assign the profile selected (in CS2: Edit / Assign profile, in CS and other versions: Image / Mode / Assign profile). You can now see the correction applied to your converted image in the color space of your camera you then need to to profile to a standard color space such as Adobe RGB 98 or sRGB ( in CS2 : Edit / Convert to profile, in CS and other versions: Image / Mode / Convert to profile ).
Assign Profile command in Photoshop
Assign the ICC profile of your camera to your images
Convert to Profile command in Photoshop
Convert the source space of your camera to a standard color space
After conversion, your image is corrected and includes a standard color space
Copyright(c) 2010 christophe métairie photographie. Tous droits réservés.