A couple of weeks ago I put a post together to how to calibrate your camera using the Datacolor Checker (available here). Now it’s time to finish the workflow and talk about the Datacolor Cube and calibrating your pictures in the real world (N.B. this example uses the Process 2012 profile available in Lightroom 4 and Lightroom 5). The Process 2012 profile was introduced in Lightroom 4 and offers better control of the Shadows and Highlights of the image. To check your settings, make sure you are in the Develop module, choose menu option Settings / Process, 2012 (Current) should be displayed.
Before we do anything with the Cube, we should turn on the Lens correction inside Lightroom. Lens correction makes sure that any lens vignetting and pin cushioning are removed from the image. You can turn on lens correction in the Lens Correction panel (Yellow) using the check box on the basic tab or on the profile tab, in this case, the lens was chosen for me based on the meta data that was supplied from the image during the import.
Based on the previous post on calibrating the camera and lens using the Datacolor Checkr (available here) the colour profile has also been applied (Red) and the colours have been corrected based on this calibration.
The Datacolor Cube is in the scene and the grey/white side is facing the light source (in this case the sun) and the black trap/side is facing the camera. I have metered the scene to make sure that i get the correct exposure. As a result you can see that the histogram (Orange) is perfect and has tone across the highlights, mid-tones and shadows and isn’t clipping anywhere. (You will see that the actual F stop used was f4.8 and not f4, this will cause the exposure to be slightly underexposed (Aperture ring slipped slightly when taken these photographs). Most Light meters are not calibrated when they are made. To calibrate it head over to Frank DoorHof’s blog and follow the instructions there.
The cube is designed to make sure that my images look correct based on calibrated settings. It will do quite a few different things :-
- 1. Set the correct white balance (this is not part of the profile that the Spyder Checker created).
- 2. Enable me to set the correct white and black point for the image
- 3. Correct the Exposure
The Technically the CUBE is defined to provide :-
- 1 Chrome Ball Measures catchlight to analyze specular highlights.
- 2 White Face(s) Define highlights in relation to catchlight.
- 3 Gray Face(s) Measures color temperature and midtone response.
- 4 Black Face Defines shadows in relation to black trap.
- 5 Black Trap Defines absolute black.
It doesn’t matter that the cube is the first picture, as long as you do it at some point during the shoot.
STEP 1: Set the White Balance
The White Balance tool is used to set the colour temperature of the scene.
You can see that the White Balance (Red) is taken from the camera ‘WB: As Shot”, the scene looks a little warm to me, so let us set this, set the White Balance. Click on the Eye Dropper (in the Red box) by clicking directly on it and it will be selected). Then click on the lighter of the grey faces using it. The White Balance will change (if required) and this will be the correct White Balance for this scene.
You can see in the following image, the new white balance (White Balance is now 5000, which is much cooler).
STEP 2: Exposure
Adjust exposure so that none of the color channels are clipped in your RAW converter’s histogram. Keep an eye on the Cube in the image for reference as you make this adjustment.
Inside Lightroom, make sure that the Highlight/Shadow clipping indicators are turned on, you can do this by clicking on the up arrows within the histogram space (Blue) (this should be displayed now with a white border). You can also turn both highlight and shadow clipping on using the keyboard short cut key ‘J’.
Move the exposure slider to the right until the bright specular highlight in the silver ball turns red (Blue box) (for extra information the brighter of the white sides now reads R99.2, G99.2 and B99.2 in the histogram (Red box)). You can also press the ‘ALT’ key whilst moving the Exposure slider to see when the highlights are starting to clip, if you don’t want to have the Shadow/Highlight clipping on all of the time. If the bright white side of the Cube starts to clip, and you see the Red appear, back off slightly, you can also type the numbers in to the Exposure values for more control.
You should see a very snug fit between the end of the highlight (right hand side) of the histogram box (Red box). (N.B. Having looked at this exposure in more details the aperture ring moved during the shot and it used f4.8 as opposed to f4, thus causing an under exposure).
STEP 3: Brightness
Next, brightness can be adjusted to compensate for lightening or darkening that occurred during exposure adjustment. Check the RGB values of the lighter of the gray faces; this face is designed to represent 18% gray, and can be used to determine how light or dark image midtones should be. You are able to alter and work on this value by slightly altering the Exposure value and make sure the mid point is where you need it to be (it isn’t hard and fast to be at 18%, it may be under or over, depending where in the scene you need it to be to make your image look amazing).
You can see in the histogram (Red) that the grey tones are now R 85.6, G84.8 and R85.2). We will check this actual value in Photoshop CC in the next step to see it as a percentage.
To test the values i am going to load the image in to Photoshop and see what the actual value of the Light grey face is, you can see that the value is now set to 18%, which means that the exposure is correct.
STEP 4: Blacks
Finally, set your black levels using the blacks slider in the Basic panel on the black trap. There should be a clear distinction between the black surrounding face and the black trap. If there is no seperation once the black trap has been set, you can use the shadows slider to create slight seperation.
You can see in the following image, as soon as i start to move the Blacks slider (Red), not only does the area under the ellipse (the Black Trap) go to black (displayed in blue) but the rest of the face goes to black as well.
To fix this we need to open the shadows using the shadows slider. You can see that by moving the shadows slider (Red) to the right we start up open up this area (Yellow). It will have an impact on the Black Trap, you will just need to work with both the Black and Shadow sliders to achieve the desired result.
Datacolor do recommend that the order of steps should be 1,2,4 and 3 because the mid-tone can shift in step 3, however this example was done with steps 1,2,3 and 4. As a final check you may want to go over the settings once again and check the values and the histogram.
You can see the final image below. Notice the shape of the histogram and that the ends (Highlights and Shadows are snug to the end of the histogram box), also there is a slight bit of clipping in the shadows which adds contrast and punch to the image. The only area that is clipping in the highlights is the silver ball at the top of the Cube. This is a perfectly calibrated image. The next step will be to use this across the other images on the shoot.
You can see the other images that i shot in the Survey mode view below. There images are straight out of the camera, and other than having a crop applied to tidy up the composition, have no other adjustments applied.
To make sure that the other images have the same settings, select the image that has the cube adjustments applied to it. (Notice the light grey box around the image in the film strip.)
Now in addition to this image, select the images where the adjustments need to be applied (i have used the CMD key on the MAC or CTRL key on the PC to select individual images that i want (i could also use the Shift key to select a range of images).
Then press the ‘Sync’ button (Red).
Here is the minimum set of adjustments that you are going to synchronise across the pictures, these settings are a representation of the changes that have been made to the calibrated image (described above), (including the colour profile for the lens and body from the Spyder Checkr (previous post), the Lens correction tab for automatically removing any lens issues, as well as the adjustments for the Cube white/black and exposure settings.
Press Synchronise, this will apply these settings to the other images.
You will see that Lightroom applies the adjustments to the images as soon as you press the button.
Of course you may need to tweak each image and make sure that it looks ok. But you can see by combining the Spyder Checkr, Spyer 4 Elite and the Cube, you can create extremely consistent results with the correct histogram and tonal values. Also the calibration process here is exactly the same in Adobe Camera RAW that comes with Photoshop.
Here is the link to the Datacolor website.