exposure-bands

exposure-bands

generate successive bands of gradually increasing exposure.

This is useful when testing and prototyping image-rendering transform and you need to evaluate its render against different exposure of a same source.

design

Be aware that to be dynamic as possible the node generate the exposure bands on different frames. This implies also having tcl expression using the frame variable which can sometimes lead to unstabilities.

adding dynamic text on each band

It's possible to add text indicating the exposure value of each band without manually creating a text node for each band, however it's a bit tricky:

• Go inside the node
• Between the 2 internal nodes add a ModifyMetadata node
  • add a single _bands_exposure key
  • as value of that key put the tcl expression [value parent._exposure]
• Add a Text node after the ModifyMetadata
  • in the message put the tcl expression [metadata _bands_exposure]
  • configure the Text node as you wish

Why using a ModifyMetadata node ?

This is the only hack I found so Nuke properly pickup the band exposure for its correct frame (remember the tool use the frame-range to work).

Tip

If you are using the tool for evaluating image rendering you probably don't want the text to be affected by it, so you will have to put an OCIODisplay node or whatver you use for your image rendering before the text node but after the first internal exposure node.