ACR Camera calbration

Nikolai

Does anybody use it? :dunno
If yes, how? :scratch
TIA :bow

colourbox

I've never tried it, but this is a CS how-to article that people get pointed to as a good example.

LiquidAir

Yes. I started using calibrations of my camera using a Gretag Macbeth color checker about a month ago and am working on refining the technique. I am (slowly) working on a tutorial for my methods. As I have time, I'll try to get some of my process on line for folks to look at.

Nikolai

Colourbox,

colourbox wrote:

I've never tried it, but this is a CS how-to article that people get pointed to as a good example.

Thanks!

colourbox

I almost forgot. When you read that article, be sure to read the author's comments in the "Read User Responses" question, because he added some amendments to the article.

Given how much we are still learning from the author, it is extremely sad that the author has just passed away, as noted elsewhere on this forum.

Duffy Pratt

What are you trying to achieve with camera calibration?

I understand the goal of having a predictable result between your monitor and your printer. And I understand why one might as close a match as possible between different monitors. But I'm not sure I see the point of camera calibration, and I'm pretty sure its just my ignorance.

Duffy

Nikolai

Duffy,

Duffy Pratt wrote:

What are you trying to achieve with camera calibration?

I understand the goal of having a predictable result between your monitor and your printer. And I understand why one might as close a match as possible between different monitors. But I'm not sure I see the point of camera calibration, and I'm pretty sure its just my ignorance.

Duffy

Being a control freak, it drives me nuts where I see a bunch of controls and have no clear idea how to use them.

Being a programmer, I have a hunch that those controls do something useful, otherwise they wouldn't waste time on making them 20% of the ACR functionality.

Finally, I suspect that setting those controls right may save me some time. I'm also not fond of the tought that NOT having them set right may impair my ability to control the color in the most efficient way.

That's basically my reasonings...

colourbox

Again, I feel stupid posting because I haven't actually done a calibration, but I think they are there in case you always have to make the same corrections when you import images. Maybe you've noticed that no matter the shooting conditions, the Auto settings always produce a white balance that's too warm by the same number of degrees every time. As I understand it, the calibration is there so that if you feel the built-in camera profile created by Adobe doesn't quite represent the particular unit you got off the assembly line, you can compensate and reduce the corrections you have to make.

I'm not quite clear on how different that is from creating new Auto defaults.

Nikolai

Well,

colourbox wrote:

Again, I feel stupid posting because I haven't actually done a calibration, but I think they are there in case you always have to make the same corrections when you import images. Maybe you've noticed that no matter the shooting conditions, the Auto settings always produce a white balance that's too warm by the same number of degrees every time. As I understand it, the calibration is there so that if you feel the built-in camera profile created by Adobe doesn't quite represent the particular unit you got off the assembly line, you can compensate and reduce the corrections you have to make.

I'm not quite clear on how different that is from creating new Auto defaults.

In the link you mentioned Mr.Fraser suggested that they may only be used under the titghtly controlled environment. What I don't get is why to have an extra tab with six more sliders on it for what seems to be easily fixed by having a shot of a gray card and using the WhiteBalance picker tool...

LiquidAir

Color calibration does not change your white balance. What color calibration does do is adjust the hue and saturation of your red, green and blue channel but it is applied after the white balance. None of the sliders in the calibration tab will have any effect on the neutral tones in your image.

The most common use of color calibration is to get accurate color. While perfect color reprocuction across the entire spectrum is not possible with current DSLR sensor designs, the calibration process lets you at least choose your priorities so that the colors you care about are reproduced accuractely.

Once you have learned to get accurate color, you will likely decide that you really don't want accurate color for most applications. Settings in ACR that give a good reproduction of a color chart yeild flat and lifeless photos for many subjects. Worse than that, if you use an accurate color calibration for ACR and then use the curves to pump up the contrast, you will often end up with oversaturated color.

Where I am headed is in the direction of building a set of calibration targets. A calibration target (in my sense) is a set of target LAB values for the color chart. Rather than using the published values (either Bruce Lindbloom's or Gretag Macbeth's), I pick my own modified set of target values and adjust the calibration, brightness, contrast, and curves to hit that that target. I am putting together a set of calibration targets that look a little like the Canon picture styles: faithful, portrait, velvia, etc.

Once I have defined a particular calibration target, I start building ACR parameter sets for that target. For instance, here is a sample parameter set:

5D DL +2/3 Portrait

This paramter set means I shot the color checker on my 5D in daylight overexposed by 2/3 of a stop and the parameter set takes that image and adjusts it to my standard portrait calibration target. Note that this is full paramter set for ACR, not just a calibration set.

The primary goal of this process is to take all my pictures from a particular shoot to a standard place. In principle this allows all of my Photoshop work to be identical and give me a consistant look across the shoot. I have not yet worked out all the bugs in the system, but when I have smoothed out the process I intend to write a tutorial.

Nikolai

L.a.,
Interesting approach, thank you for sharing.

However, I can only see it to be an effective time saver if you are getting TONS of shots in the nearly identical lighting conditions. Which kinda leads to the idea of totally controlled enironment, aka studio, etc. Brings back the memories of the days when a studio would purchase a whole batch of film to make sure all the rolls have identical response, would deal with only one lab to develop and only one printer to print...

I personally lead way less organazed and "controlled" photo-life to be able to benefit from such a highly methodical approach. My environments change like crazy from one shot to another...

Hmm, mebbe I'm in the wrong hobby :-)

Once again, thank you for the input!