Selective color manipulation?

[clouzot]

Hi all,

Is there a way to achieve something akin to Photoshop's "selective color" in Startools?

While Startools isn't a general purpose photo editor, there are cases where I'd want to slightly alter the colors it yields. In some cases, you can even tell if a picture was processed by Startools, because of its typical cyan + deep red colors (which is good for scientific exactness, don't get me wrong )

For instance, if I want to alter the bright cyan stars to give them a deeper blue color, the only way I know of is to put some bias on the blue channel. This, in turn, changes everything in the image (the background gets a blue cast, other stars in the field end up being unbalanced as well).
I could probably use masks and apply Color in multiple stages, but is there a better way?

Thanks

[admin]

There are a few ways to modify colors selectively, if that is really something you'd like to do.

1. You can use the Similar Color brush to select contiguous areas of similar color (for these sorts of manipulations).
2. You can use the Filter module (with and without star masks) to perform all sorts of color-based manipulations.
3. You can use the Color module (with Tracking off) with a mask.
4. You can use the Color module (with Tracking off) without a mask, and use the Layer module to blend a modified result with the original image (click Undo -> Background), for example using a Brightness Mask (for example "Where foreground is dark, use background") and vary the Brightness Mask Power to have the color modification only impact the highlights.

Does that help?

[clouzot]

Thanks Ivo,

Among the options you listed, the one that kind of worked for me was to run the Color module a second time (after the base color balance) with a mask using "select similar color". It's a bit of hit or miss because you never know how restrictive it is in selecting pixels that belong to a given color, but that allowed me to do (in three successive passes) an horrible purple, yellow and green galaxy that my daughter liked very much.