Request for CMY color model for Levels Curves and other Adjustments

[shijan]

Is it possible to add somehow CMY Subtractive color model https://simple.wikipedia.org/wiki/CMY_color_model for Levels, Curves and other possible Adjustments?

"Therefore, the difference between the CMY and the CMYK color model is, that the CMY color model assumes that it is possible to mix black by all of the three pure colors and the CMYK color model uses black as an additional color."

[Hoogo]

Is it more than RGB inverted?

[shijan]

How could it be related to RGB inverted? CMY is a color model that came from color film emulsion.

[der_fotograf]

Just name 5 (!) real world advantages of using CMY instead of CMYK or RGB.

Cameras deliver RGB images. Software runs with RGB and according color profiles. Prepress uses RGB images (provided the RIP does handle PDF/X-3 or PDF/X-4) or RGB images converted to CMYK images. Large format printing uses RGB or CMYK images. Laser Printing uses RGB or CMYK images. Displays and monitors use RGB images. PDF proof tools use RGB and/or CMYK color models. 99% of all professionals in photography, design, and printing think and use either RGB or CMYK color models, but not CMY – for a very good reason!

Just a few users want to use the CMY color model and have it implemented into PL?

There are tools and software out there that let you work with CMY color models. Reach out, purchase them, use them. But please don't request this model for PL.

[shijan]

go away

[Hoogo]

How could it be related to RGB inverted? CMY is a color model that came from color film emulsion.

Because they are opposite colors. Instead of adding Yellow, you can remove blue.
Here I have a gradient from white to black. I inverted it and added an inversion curve on top, so it looks still white on black.
Now you have CMY controls, just with wrong RGB caption.
I adde some yellow to white $00, and removes some yellow from black %FF.

CMY.jpg

[shijan]

That's interesting. I never looked to color wheel from this point of view. But anyway native support in Adjustments would be simpler than using Curves like you explain. Currently many apps advertise color correction option in CMY, so i expect something like this:

[Herbert123]

Currently many apps advertise color correction option in CMY

"many apps" - which software exactly? The big ones do not as far as I am aware: Affinity, Adobe, Corel, Krita, Gimp, PaintShop Pro, ... I am unsure how many users would actually make use of CMY space adjustments to warrant an implementation of a CMY option in all the adjustments.

And it is already possible to work with a CMY workflow and any other adjustment in PhotoLine. Not only via Hoogo's method but also by:

1) create two virtual copies of the original layer.
2) group them and ensure Draw Isolated is TURNED OFF. If not, it will blend the group as RGB instead of CMY
3) Select the bottom (original) layer. Turn on the R channel only, turn off both G and B. Name this "Cyan"
4) Select the second layer. Turn on the G channel only, turn off both R and B. Name this layer "Magenta"
5) Select the third layer. Turn on the B channel only, turn off both R and G. Name this layer "Yellow"

Congrats! You now entered the wonderful world of CMY adjustments! CMY channels can now be edited and adjusted.

Create a simple action to automate this.



PLD example:
https://filetransfer.io/data-package/H6TXGvTd#link

Message for the Hubers: I noticed that playing around with the channels in this way would lead to a corrupted thumbnail preview for the group (zoom in and out with ctrl-mouse wheel) and even in the main view at certain zoom levels. It seems to be a bug related to activating "Draw Isolated" together with turning off one of the layers in that group for the parrot group and zooming in and out.

[Herbert123]

Btw, I used this workflow before for splitting RGB channels. It is pretty cool that PhotoLine allows for specific channels to be controlled this way. Very very powerful, and a heck of a lot more elegant than fooling around destructively with channels in Photoshop, for example.

So kudos to the Hubers for implementing it a few years ago.

[shijan]

Recently i watched video tutorial about Imacon scanners software and noticed that their Curves tool can work in CMY mode. So i downloaded example package of scanned images and test it in real life. I noticed interesting logic:
RGB curves works very well and logical if you need to remove color cast (Image looks too green -> lower Green curve)
CMY curves are more logical and human friendly when you need to create artistic color correction or add color cast (I want warmer image -> increase Yellow curve)

Screen-Shot-2024-06-01-at-7-55-03-AM.jpg

[russellcottrell]

As previously stated, CMY curves are just inverted RGB curves.
If you want a warmer image, create a curves adjustment layer and set the blend mode to Color; decreasing blue will then be identical to increasing yellow, and so on.