RGB CMYK LAB and Dan Margulis !

[cricket1961]

Originally Posted by Markzebra

Thanks for the compliment Chris. Much appreciated.. it does have its limitations and can look more powerful on first glance than is the case in practice unfortunately: Remember that the master document still needs to be in a single color mode. So your LAB Smart Object is converted back to RGB each time you save.
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Ah, but when I saved down a RGB master image with a cmyk smart object and closed it and reopened it, the smart object was still CMYK.
Conversely, a master CMYK was still retaining a RGB AND a L*ab smart object.

This is great, at least for my workflow.

Chris

[Sistere]

Originally Posted by edgework

As Dan likes to say, every file has 10 channels. Even if you don't need CMYK for output purposes its four channels are a great source of targeted masks. Borrowing a black plate for use as a layer mask in RGB and LAB gives you a shot at much more refined shadow work than either space is capable of simply using master RGB curves in luminosity mode

Well said...Edgework. Extremely useful and most importantly...pretty damn practical. In fact, I printed it out and stuck it on my wall over my monitor for reference since I am still sucking my pacifier in regards to using CMYK & LAB.

Thanks for taking the time to sit and write something meaningful and not just a criticism or opinion.

Damien

[Kevin Connery]

Originally Posted by mayday

The Dan Margulis book Professional Photoshop is great but I think he makes it a harder read than it needs to be!

It IS a tough read, but the simplified versions used in 2 other authors' books took longer to cover less material and in less depth. I'd prefer a book which can be re-read to something which doesn't give as much coverage.

The LAB book is, however, much easier to follow, in my opinion.

[mayday]

Originally Posted by Kevin Connery

It IS a tough read, but the simplified versions used in 2 other authors' books took longer to cover less material and in less depth. I'd prefer a book which can be re-read to something which doesn't give as much coverage.

The LAB book is, however, much easier to follow, in my opinion.

Don't get me wrong its a great book, and for its information one of the best around, just not sure I like his writing style.
I have'nt read the LAB Book yet but looked through it and it seems better and more direct.

[Markzebra]

Fiddling around today I realised that you actually CAN hide channels in the Smart object file by unchecking the channels in the Advanced blending options - For example if you wanted to blend The A channel of LAB with your RGB document, open your LAB smart Object, Option Double click the Base LAB and turn off the L and B channels. Now save the smart object- your A channel will now appear intact in your original RGB document, converted to 3 channel RGB obviously (weird) but still useable. There you go even I learned something today.

You are welcome to use this Chris. By the way, what part of your workflow uses this? For me its alpha's and Getting a K density channel into RGB

[mayday]

Another great finding Mark! you offer some of the best advice and techniques on this site

[cricket1961]

This will allow for the adjustment of the black channel in RGB mode. Or certain calculations that work better in CMYK than RGB.
My softlight retouching is a lot harder to do in a CMYK file (more pressure needed)but now I can have a RGB file embedded and not have to worry about converting to CMYK at the end. Filters that work on RGB files but not CMYK are useable now. The list goes on and on. Having a CMYK base with a RGB smart object to tweak or filter. And within the RGB object, a L*ab object to change color or calculation masking.

Mark, I can write a whole book about just this one technique.

Chris

[Markzebra]

"and not have to worry about converting to CMYK at the end" - here's is a technique, You can have an empty "container CMYK" file with your working file as an embedded RGB. its possible to merely change your destination profle (lets say Euroscale or GMG) simply by using Assign profile on the CMYK master. No destructive after the event CMYK to CMYK coversions necessary any more if you set your files up this way. You can set up a droplet for each CMYK destination space which simply opens the file ASSIGNS the profile and then saves a copy. Non destructive CMYK to CMYK effectively using the embedded master RGB as the source each time. Pity most studios don't bother to get their heads around this stuff.

Smart objects are still too new to be used my most I've found. "Instances" too, occurances of the same Object used multiple times in a document, is another feature with a great many uses, each instance can be a different in every respect except the base pixels. This has mind boggling potential.

[cricket1961]

Now you are seeing it Mark! Way to go! Exactly what I meant by no more conversions to cmyk.
And each smart object can have multiple smart objects within. Even illustrator objects!

Like I said. This is huge.

Chris

[JMB]

I can write a whole book about just this one technique.

You better start to do that and I sure will buy it! XD

[pixel_monkey]

This is good stuff. Thanks for this very nice tip, Mark. This is probably the greatest approach to nondestructive retouching I've ever seen. The possibility is immense if not endless.

[KR1156]

mark, chris....can you help me understand this a little better.

having the working RGB file inside a container cmyk file, going back to your RGB embeded file, the working file everytime you want to do a direct RGB to cmyk conversion. is that the point? instead of cmyk lets say euro to cmyk us sheetfed.

i must be missing something, and sure i am. it just sounds the same as, let's say i have an RGB master file. if i need different RBG>CMYK conversions, why not just go back to the RGB file and do separate save as files each time i need a different cmyk conversion. what does the embeded RGB method do that's better than save as steps?

im just having trouble following it. i get the channels and filters and blending, just not following what is so different about the conversions.

thanks

[Sistere]

Hey guys,

Just wanted to drop a line and say that I took some peoples advice and ordered the two main Dan Margulis books listed in this thread...had'em overnighted from Amazon.

I've spent most of today with the LAB book and must say that in the little bit I have actually gotten down...the way I retouch is forever changed! Seriously!

If anyone is contemplating buying one or both of the main Dan Margulis books...but maybe are gun shy of spending the cash...do it! There are so many things I thought I knew but now realize I didn't know as well as I thought. (What?)

Thanks for the book tips guys.

Damien

[Markzebra]

Your right KR1156 - there is nothing different about it - you are effectively converting from your RGB master using whatever profile setup you have in color preferences (another flaw I agree). What makes a big difference to me is the whole thing is embedded in a single file, this is what gets confusing working with other people, having many different versions floating around - RGB, CMYK Euro, GMG retouched CMYK - maybe some pap file someone has converted using default SWOP - and THEN repurposing these CMYK files - disaster. Thats all.

There is nothing different about the conversions, and they are also flawed in that whatever rendering intent, black point you have set up in Color Settings will always be used. BUT ... if you know what you are doing its a great way to keep things clean.

[KR1156]

i got ya mark, thanks for the clarification....i thought i was missing something and it was bugging me!

but i do like a very clean, smart & simple workflow...so we're on the same page.