Why does Photoshop make you switch colorspaces?

jfriend

lately, I've gotten more and more interested in using features in Photoshop that are only available in color modes other than RGB such as A, B or L curves from LAB, K curve from CMYK, blend-if settings using A and B values, sharpening the L channel, using all 10 channels as potential masks, etc...

What I find is quite a pain in Photoshop is having to switch color spaces in order to use these different features. Besides the potentially destructive issues with switching to CMYK, you often lose your layers, blend modes, etc... when you switch color spaces, you generally have to flatten your image.

Why, for example, can't I be in RGB and use a blend-if settings versus the A or B channel which is often the easiest way to target an adjustment to just a particular area of your photo? Photoshop can display the A and B values in the info palette. It can know what the A and B values will be.

Why can't I have a heavily layered document in RGB and decide to use the K channel as a mask without having to do lots of gymnastics in order to get the K channel?

BinaryFx

I am not a programmer, but I presume that this would have to take place behind the scenes "on the fly" and then blended/combined back into the RGB working file - all hidden from the user. Currently, you do that manually.

The curvemeister.com curves plug must do something similar, one's file can be in RGB but one can curve in LAB, HSB Wide Gamut CMYK or RGB and when you leave the plug the original file is still in RGB...but there is no free lunch, somewhere a conversion and other similar steps must take place to access these channels.

You are asking for a "automatic transmission" version of Photoshop, when we are all used to changing gears manually. Both have pros/cons.


Stephen Marsh.
http://members.ozemail.com.au/~binaryfx/

jfriend

BinaryFx wrote:

I am not a programmer, but I presume that this would have to take place behind the scenes "on the fly" and then blended/combined back into the RGB working file - all hidden from the user. Currently, you do that manually.

The curvemeister.com curves plug must do something similar, one's file can be in RGB but one can curve in LAB, HSB Wide Gamut CMYK or RGB and when you leave the plug the original file is still in RGB...but there is no free lunch, somewhere a conversion and other similar steps must take place to access these channels.

You are asking for a "automatic transmission" version of Photoshop, when we are all used to changing gears manually. Both have pros/cons.


Stephen Marsh.
http://members.ozemail.com.au/~binaryfx/

I'm sure it would take more advanced programming. But because the conversion from RGB to LAB or from RGB to CMYK is deterministic (e.g. it's just a math transformation), it should just be more math in order to apply a LAB curve while in RGB mode.

Since you mentioned a car analogy, I see it more like each colorspace is a garage where we can work on our car with the particular set of tools available in that garage. When we want to move from one garage to another to get access to a different set of tools, we have to pack up our car and flatten things like adjustment layers and some blend modes or blendif settings so it's pretty inconvenient to switch garages. So ... all I'm asking is if Adobe could just bring all the tools to the same garage so we could use them all in one place without having to constantly switch garages (and thus flatten our image each time).

DavidTO

John,

I think that having LAB rules in RGB mode would confuse the crap out of most users.

jfriend

DavidTO wrote:

John,

I think that having LAB rules in RGB mode would confuse the crap out of most users.

Obviously, it's an advanced thing. I'm not sure why it has to confuse. Rather than just offering RGB curves, you also offer LAB curves or CMYK curves. If you didn't know what those were you'd ignore them and just keep doing what you were used to. If you did recognize them, it would be obvious what they were.

Do you not think it would be useful to have access to A, B or K curves while in RGB mode? To be able to apply an A or B blend-if setting to a layer while in RGB mode?

They already do some LAB-like things today by giving you a luminosity blend mode and color blend mode in RGB. Those are not native to RGB and require LAB-like functionality in order to implement. It's even rumored that the internal data structures used by Photoshop are actually LAB-like and that's why they can offer luminosity and color blend modes in the first place.