Nuke: Set white balance

I just saw a really great tutorial about setting the wb in Nuke at the Foundry site. We do this using the grade node.

1. Add grade node to the image you wish to correct the white balance in. In the blackpoint enable the eyedropper and Shift + Alt + Ctrl drag an area you consider as the darks in the skintones. It is important that we use all 3 modifiers to sample the raw data of the image not the data with the adjustment added to it. ( this will cause a “loop” and the image will flicker in the viewport).
2. Repeat the process with the whitepoint and sample the highlight area of the skin you want to match.
3. Now we start sampling the clip we want to match to. In the lift sample the corresponding dark tones in the image we want to match the wb with. Note we don´t need to hold the alt modifier since we´re not grading the image we´re sampling.
4. Do the same with the gain. Sample the highlight area. Done !
5. We can do some additional color adjustments to get even closer.

American Beauty

Sometimes there’s so much beauty in the world I feel like I can’t take it, like my heart’s going to cave in. 

Nuke: create node

To create a node in Nuke use the following cmd. The second line simply deselects the node.

b = nuke.createNode(‘Transform’)
b.knob(“selected”).setValue(False)

Nuke

After being curious and wanting to the step up my comping skills I have downloaded the Nuke PLE and starting to look into it. Altough After Effetcs still will play a part in my motion graphics tool box I think that when it comes to pure comping work ( 2d and 3d ) nuke is the way to go.

Nodes

To spawn a new connection shift + LMB drag an arrow.

To extract a node shift + ctrl + LMB drag

Transformation

up, down, left, right on the numpad will nudge the tramsform node. Ctrl (small) and shift (large) works as modifiers.

change pivot of transform node press Ctrl LMB move the transformation jack.

Timeline

Set the in & out point. Ctrl LMB click on either side of the playhead to set the in & out point.

Zoom the timeline. MMB click and drag to focus on selected segment. MMB click to reset.

Graph Editor

Insert keyframe on f curve. Ctrl + Alt LMB click the curve.

Move curve in both axis Ctrl + LMB click the keyframe.

Unlock tanget handle Ctrl + LMB click the keyframe.

Attributes ( parameters )

To copy an attr Shift + Ctrl LMB click n drag from one attr to the other.

To link an attr Ctrl LMB click n drag from one attr to the other.

Virtual slider. Alt LMB drag. This is context sensitive. If your cursor is placed at the 10 the 10 will be affected.

Up  down arrow will also modify the attrs. Place the cursor next to the digit you want to change and step up down. Move left or right to change the increment size.

Slider

To reset a slider Ctrl + LMB click the slider

Expressions

To link an attribute to another Ctrl click the driving Attr and release on the driven Attr.

To access the expr window place the cursor in the attr field and press =

random(frame/10)*10-5

sin(frame/10)*10

Format

Fit = width

Fill = Height

Color & Image Processing

If reading a premultiplied image make sure to enable the premultiply checkbox in the read node. Also if writing out a premultiplied image enable the premultiply cb i the write node.

Colorwheel & eyedropper. The eye dropper is lokaded next to the colorwheel icon. It is a toggle with constant color / colorpicker. It is a good idea to turn it off when you´re done with it. To sample a color toggle the color picker and Ctrl drag a box on the image.

The sampler node (color) will draw a graph of a scanline across the image and display values from o – 1.

To set the whitepoint of a colornode with a eyedropper without nuke fliping back and forth (sampling the corrected uncorrected image) press alt + ctrl and LMB click and drag.

To reverse a colorcorrection simply make a copy of the node place it downstream and enable the revers checkbox.

Color lookup node can be used to match two diferent shots. To do this simply add a color look up node to the image you want to match. Enable the eyedropper nect to the source attr and ctrl + shift LMB click and drag an area of the image you want to change. ( Make sure that you select an area on bothe images that you define as a midtones otherwise it will not work ). Then repeat the same process on the target attr and shift + ctrl LMB drag the target image. Hit Set RGB to match. Repaet for the Highlight areas to match highlights. If you´re working with an floating point image the “keyframe” at 1.0 can be removed.