Adobe DNG Profile editor, primary grading done right!

[shaocaholica]

http://labs.adobe.com/wiki/index.php/DNG_Profiles:Editor

New stuff from Adobe but only for still image workflow right now (unless you convert your RAW footage into a DNG sequence:thumbsup:).

Basically, you shoot a color chart from any of the leading chart makers and you load it(a single frame) into the profiler app. Because the chart patches have known values confirmed at the factory with some serious color sampling equipment, the color of the patch in the shot should be "graded" until it matches as closely as possible the expected color. You can download the chart profiles from Adobe but you can get that data from the chart maker as well.

What the profiler does is to grade for all the patches very quickly and gives you a set of tone curves to apply to get your primary grading. Its all automated so you don't have to do anything by eye or manually and you don't have to worry about throwing off a patch when you work on another patch. Its all done for you by the computer, the way it should be.

[Stefan Christou]

nice one :thumbsup:

[shaocaholica]

I just tried this out at home with my D700 and it works quite nicely and fast too.

Just shoot a color chart in the actual lighting you'll be using, load it up in the program and mark the corners of the chart. From there, the program knows the location of the color patches and samples each one. Then it creates a hue/saturation offset for each color patch so that the final color of the patch is within a very small tolerance of the actual color of the patch. So the more patches, the more accuracy you'll have although the current Adobe implementation is limited to the 24 patch x-rite chart but support for a more complex chart shouldn't be that hard.

[Graeme Nattress]

Be very careful though - colour charts are often quite different in real life. This kind of calibration is only as accurate as the chart is, and you've got to be careful to light the chart nice and evenly too. If Adobe are specifying a specific chart, I think you'll find that a generic or other brands chart be different enough to throw the results off.

This is also something I'd call "characterizing" or "calibrating" rather than "grading".

Graeme

[RobinBalas]

Be very careful though - colour charts are often quite different in real life. This kind of calibration is only as accurate as the chart is, and you've got to be careful to light the chart nice and evenly too. If Adobe are specifying a specific chart, I think you'll find that a generic or other brands chart be different enough to throw the results off.

This is also something I'd call "characterizing" or "calibrating" rather than "grading".

Graeme
Actually Adobe claims to have sampled and averaged a horde of Gretag 24 patch cards and applied those average numbers in the software, so as long you get a fresh 24 patch Gretag plate every 2 years or so you are quite safe. The lighting is very important though, but it is easy to do when you hinge a clear plastic film to the top of the card and overlay it to look for specular highlights through the camera finder. Flip it back after getting rid of the speculars by diffusing them, shoot, process and you have an excellent color match for all practical purposes (note the"practical"). I have shoot difficult art repros in the artists studio under highquality daylight balanced tubes (CRI>98) and the match after using this approach was very good both on screen and print. It totally fixed the reds which were way down with the integrated camera profile in ACR.
I would have wanted a way to enter my own colorimetric measurmenst for my Gretag plates in the new software as I have a spectrophotometer and can measure my own for top accuracy.
Also the workflow alows shooting the card in both tungsten and daylight to create/interpolate a new general cameraprofile for your cameras serialnumber wich will help some people get better general color matching when having a near off-spec camera/chip.
I really like this as it apporaches the workflow of normal ICC based softwares like Phocus, Capture1, LEAF Capture and RAW Developer.
It is one of the many positive advancements Adobe has done the last year or two after a long time with little recognition for its lacking features.
MHO.

[fde101]

Why not put the same color in multiple places on the card and average that color over the image to compensate for variances in the lighting?

[RobinBalas]

Why not put the same color in multiple places on the card and average that color over the image to compensate for variances in the lighting?

There is a Gretag card wich does that and even has more patches. However having more patches is not always a good thing as more correct often means less smoothness in gradations if somthing is misbehaving slightly as it most often does - like the fluo-tubes I spoke of.
Have a look at http://www.xrite.com/product_overview.aspx?ID=938 it uses the white,gray,black patches around the chart to calculate light fall-off and correct the readings to make lighting even. One chart like the one shown even has some glossy patches to detect specular light, but it sort of fails on that aspect as speculars often is very localized and not detected. Hinge a glossy plastic foil on top instead and you will see in an instant if there are some problems.
MHO.