Yesterday we briefly discussed auto-generating color palettes from specific images, and mentioned that one use for this feature is to re-colorize images or movie frames to match the color aesthetics or mood of a particular image or painting you like the color aesthetics of. This post will discuss the methodology of how to do re-colorization based on a custom color palette.
Auto-Generating a Custom Color Palette from an Image
I choose 2 different impressionistic paintings to use as color sources for this post. For each one, I first loaded them into Studio Artist as source images. I then ran the Edit : Color Palette : Generate from : Source Image menu command to generate a custom color palette derived from the source images. You can see the respective source images and their auto-derived color palettes in the gallery below.
For each of the 2 re-colorized examples images shown at the top of the post I started by first loading the source image I wanted to derive my auto-generated color palette from. And I then ran the Edit menu command described above to generate the custom color palette from the source image. I did not record these 2 preparatory steps in the paint action sequence (PASeq) I then built for colorizing an image or movie with the custom color palette. I was able to record my custom color palettes into the 2 PASeqs I recorded. How I did this will be discussed below.
Re-Colorizing based on a Custom Color Palette
The paint action sequence below shows the 3 processing steps I used to generate my custom colorization effects. Note that I could have eliminated the first set the canvas to the source image action step by setting the second Color Palette map ip op action step so that it’s IP Source parameter was set to the Source Image option. I build the PASeq the way I did to help visualize the various processing steps, so you can see the original source image and then the effect of the re-colorization and subsequent contrast boost action steps.
The first action step just records erasing the canvas to the source image. The second action step used the Color Palette Map ip op to recolorize the canvas based on the contents of the current Source Color Palette. Note that for the first example at the top of the post I set the Option parameter to Smooth. The different Option settings will re-colorize the Ip Source for the effect in different ways.
Smooth tries to choose the closes 2 colors to a given input pixel in the color palette, and then smoothly interpolates between them based on the Map Type color space distance between the pixel and those 2 palette colors. For the second example at the top of the post I used the second custom color palette we shoed above, and the Force Smooth setting for the Option control. Force Smooth forces all of the individual color palette colors to be used when rendering the complete image. Smooth will only use the colors in the palette closest to the original pixel color values.
Note that I want to record my custom color palette into the actual PAseq, so that when I export it and import it at a later date my custom color palette will be used when the Color Palette Map ip op is run (as opposed to whatever happens to currently be in the Source Color Palette at that particular time). The key to doing this is to turn on the Pal/Grad Playback parameter at the bottom of the Color Palette Map ip op Editor control panel. Note how I set it to Reset (as opposed to Don’t Reset).
Image operation action steps always record the color palette and color gradient states as they were when the action step was recorded. But they will only play back the recorded color palette and color gradient if the Pal/Grad Playback control is set to Reset for the effect.
The 3rd action step in the PASeq just uses the Image Compressor ip op to mildly adaptively boost the output image contrast. When using this step with movie processing you may need to back off on the Local Adaption control setting to avoid introducing strobing artifacts into the output movie processing, depending on the source material. You can always use the Blur ip op with an Edge Composite setting and a Blur of 99% to generate a contrast boost effect that doesn’t strobe if you do run into this issue.
The image gallery above starts out by showing the 3 step PASeq used for the re-colorization effect. I was processing a movie file, so the 2nd gallery image shows the source image with the loaded original source movie file. The 3rd and 4th gallery images show off the Color Palette Map and Image Compressor Editor control panel settings for the first colorize effect shown at the top of the post. The 5th, 6th, and 7th gallery images show the output for the 3 action steps respectively. The 8th gallery image shows how I slightly modified the Color Palette Map Editor settings for the second colorize effect, that used a Force Smooth as opposed to Smooth setting for the Option parameter (as discussed above).
You are always free to use any of the color palette hot key options to hand edit the automatically derived color palette, if you want it to have more contrast, have a different hue focus, etc. You could also build a custom color palette by hand picking colors and option clicking on individual color palette memory cells if you wished to. Here’s a link to a tip on hot key editing options for Studio Artist 4.
