The Maxwell Render plug-in for Photoshop provides a useful action to make certain adjustments in your renders, similar to the Multilight adjustments in Maxwell Render.
Loading the action
Open Photoshop, and in the Actions palette menu, select “Load Actions” and browse in the folder where you have the “Maxwell Actions.atn” file. A new action group called “Maxwell Actions” will appear with a “Maxwell Layer Adjustment” action inside. Next time you open Photoshop, the new action will already be loaded in the Actions palette and ready to use.
- Windows: The PS action is installed in the following folder (Windows 7): "C:\Users\username\Documents\Maxwell\Maxwell Plug-in for Photoshop".
- Mac OSX: The action is included into the plug-in compressed package. Just unpack it.
Using the Maxwell Render action
This action was created to mimic the light intensity and color adjustments that are possible in Maxwell Render using the Multilight feature. You only need to launch your renders with the Intensity Multilight option enabled (Color Multilight is not needed here, as the color adjustments will be produced inside Photoshop).
By enabling the Multilight option when you launch your render in Maxwell Render, the render will be saved in MXI format (which is in fact a layered format), with each independent emitter contribution being imported in Photoshop as a separate layer.
If you would like your final image to take into account all the independent emitters, make sure you assign the “Linear Dodge” blending mode to each emitter layer. Linear Dodge is valid for 32 bitdepth range layers. For 16 and 8 bits it's better to use the Screen blending mode.
The Maxwell Action creates two adjustment layers to allow you to adjust the intensity or color of each emitter separately.
If you would like to make any adjustments in the intensity or color of one specific emitter (just like you do in Maxwell Render with the Multilight feature), you should select the emitter layer and execute the “Maxwell Layer Adjustment” action. Open the Actions palette, select the “Maxwell Layer Adjustment” in the “Maxwell Actions” group, and click the “Play Selection” icon at the bottom of the Action palette to execute the action.
A new layer group will be created automatically containing your emitter layer, and a couple of adjustment layers will be applied to it, named “Intensity” and “Color”, to allow you to control the intensity and color of that particular emitter.
- Move the Exposure slider up and down on the Intensity adjustment layer to increase or reduce your emitter intensity.
- Move the Hue, Saturation and Lightness sliders up and down on the Color adjustment layer to change your emitter color.
For a more precise color adjustment, a more complex “Channel Mixer” adjustment layer could be used, rather than the provided Hue-Saturation-Lightness color control. Simply disable the Color adjustment layer and assign a “Channel Mixer” adjustment layer to get a more precise per-channel color adjustment.
Use the Exposure slider to adjust the emitter intensity, and the Hue slider to adjust its color.
As Adobe Photoshop cannot manage the spectral information from Maxwell Render images, the Color adjustment layer can only mimic the high precision spectral changes that Maxwell Render performs, so this poses some limitations. The Color adjustment action performs a hue-saturation change, so it is not possible to change the color of a pure white emitter. In this case (and in general with pure white, grey or black desaturated emitters), we strongly recommend replacing the “Color” adjustment layer with a more complex “Channel Mixer” adjustment layer. The “Maxwell Layer Adjustment” action has been tested in Photoshop CS3, CS4, CS5 and CS6.
There is a limitation in the Photoshop Standard versions (not present in the Extended versions), which means that the Adjustment Layers cannot be created in 32-bits mode. Because this action works in 32-bits and uses Adjustment Layers to allow non-destructive adjustments, it won’t work on the Standard versions of Photoshop.
If you are using the Standard version of Photoshop, you can work around this limitation by converting your render to 16-bits (without merging) to be able to use the Action, as Photoshop is able to create Adjustment Layers in 16-bits. In 16-bits you will get a better result by setting your light layers to “Screen” blending mode, instead of “Linead Dodge (Add)”. Obviously, converting a 32-bits render to 16-bits will produce a reduction of the tonal range of the render.