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Author Topic: How to swap from DARKS to the Left to LIGHTS on the LEFT IN CS6 CURVES  (Read 2815 times)

sanfairyanne

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I just got hold of a copy of Dan Margulis' book Photoshop LAB colour. It's probably way too advanced for me but I need to get involved in something. Anyway after reading a long intro' about how his book will be relevant for years to come I begin with the first exercise where he suggests I swap my Curves dialogue box so LIGHTS begin at the LEFT instead of to the RIGHT. I'm told to click in the gradient bar to make the swap. Unfortunately it's not doing anything, of course I'm on CS6 whereas the book was printed in 2006, all of which makes me wonder if I am wasting my time right from the start.

Any help would be appreciated.
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digitaldog

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Re: How to swap from DARKS to the Left to LIGHTS on the LEFT IN CS6 CURVES
« Reply #1 on: December 24, 2013, 10:42:12 am »

I just got hold of a copy of Dan Margulis' book Photoshop LAB colour. It's probably way too advanced for me but I need to get involved in something.
I'd agree (Lab is way oversold and unnecessary most of the time). If you want to get involved in something more useful <g> we can assist. ;D

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Anyway after reading a long intro' about how his book will be relevant for years to come I begin with the first exercise where he suggests I swap my Curves dialogue box so LIGHTS begin at the LEFT instead of to the RIGHT. I'm told to click in the gradient bar to make the swap. Unfortunately it's not doing anything, of course I'm on CS6 whereas the book was printed in 2006, all of which makes me wonder if I am wasting my time right from the start.

The swap (if I'm following you, and I do have that book so I'll double check) is just to alter the values or feedback (Light vs. Pigment) such the input/output values are reversed if you will. Dan pretty much only understands "CMYK" so he prefers the values be Pigment/Percentages, rather than RGB (0-255) which one could consider "Light".

If this continues to give you a headache, there's a ton of much more useful content to read or watch video wise on this site.
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Mark D Segal

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Re: How to swap from DARKS to the Left to LIGHTS on the LEFT IN CS6 CURVES
« Reply #2 on: December 24, 2013, 10:45:32 am »

A total waste of time. Leave your curves where they are. There is SOME stuff in that book which will remain useful indefinitely but you DO NOT need to alter your default curve positions to implement any of it. Much of the photographic impact he derives from the procedures in that book have since been rendered much easier to achieve in Lightroom, but there remain some image editing situations in which the creative use of Photoshop blend modes and the L*a*b* channels remains helpful. For most usual image preparation workflows you wouldn't miss that material.
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sanfairyanne

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Re: How to swap from DARKS to the Left to LIGHTS on the LEFT IN CS6 CURVES
« Reply #3 on: December 24, 2013, 11:03:15 am »

Thanks I did just figure it out for myself only to go onto the second section which again threw up hang up. So I fear this is one book for the garbage.
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Re: How to swap from DARKS to the Left to LIGHTS on the LEFT IN CS6 CURVES
« Reply #5 on: December 24, 2013, 12:52:46 pm »

Thanks I did just figure it out for myself only to go onto the second section which again threw up hang up. So I fear this is one book for the garbage.

 It will make a somewhat useful doorstop. ;D

Rich
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Ken Bennett

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Re: How to swap from DARKS to the Left to LIGHTS on the LEFT IN CS6 CURVES
« Reply #6 on: December 24, 2013, 08:39:16 pm »

Interesting. Back in 1998 or so my editor told me that I was heretofore responsible for all scanning and CMYK production for our alumni magazine. He wanted to save several thousand dollars per issue. I was already scanning for web and newsprint, so I worked with the designer to send off some color scans and get proofs made. The color was all over the map, but mostly terrible. Inconsistent, too.

Dan Margulis saved my butt. I learned how to work and think like a color printing house worker, not a photographer, and the files we sent to all of our publications' printers ended up being used with no edits. (Took me a bit :) ) The files were beautiful because they were MY work, and I wanted them to print beautifully. Not sure which book I started with, but yes, the final edits were done after converting to CMYK in Photoshop, using the appropriate profile. (Of course I started with as good an RGB scan as possible.) Once I made the transition to digital imaging in late 2000, this made the process much easier and more repeatable. Also, faster (no scanning.)

Part of the reason this worked so well was that printing shops were not set up to take RGB files at that time. They could handle CMYK from other printers or other projects (designers famously saved the CMYK print files and reused them promiscuously.) So when I sent them good-quality CMYK files, exactly sized and sharpened for the output process, they were suprised and happy. And my editor was happy. And I finally got good color repro in our publications -- and if not, it was my own fault.

These days we have far too many designers and publications for me to do this, but the print shops are much better at working with original RGB files, too. And the designers take responsibility for the color quality, and they have pretty good standards. (Did I mention how much I love my staff designers? Well, I do.)

I have not seen this particular book, but I still re-set my Curves in every new version of Photoshop so that it shows ink percentages, 0 on the left (white) and 100 on the right (solid color.) It's just how I see the world. It may be worth a look.
« Last Edit: December 24, 2013, 08:42:56 pm by k bennett »
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digitaldog

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Re: How to swap from DARKS to the Left to LIGHTS on the LEFT IN CS6 CURVES
« Reply #7 on: December 24, 2013, 08:48:07 pm »

Part of the reason this worked so well was that printing shops were not set up to take RGB files at that time. They could handle CMYK from other printers or other projects (designers famously saved the CMYK print files and reused them promiscuously.)
Which is odd. CMYK is highly device dependant meaning, you need the specific and correct recipe for CMYK or you get butt ugly output. RGB can be fashioned into the correct CMYK quite easily if (BIG IF) you have the proper conversion recipe which is in the form of a good ICC CMYK profile for the output. Old school (VERY old school) is scan once, use once and make that scan in CMYK. Note that there is no such thing as a CMYK scanner, they all initially produce RGB data. Many such scanners just spit out CMYK from that RGB data. But if you have the proper conversion recipe, that's fine. Today (well at least within this century), RGB makes far more sense. Scan once, use many! Or shoot (RGB), use many.

Here's where Dan is a master: someone hands him a turd of an image, be it RGB or more likely CMYK and he makes lemonaid from the lemon. Have you seen the awful photography he uses in his books? Any improvement, and there are improvements from his process, looks far better. Lesson: Don't start with turd images.

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Theses days we have far too many designers and publications for me to do this, but the print shops are much better at working with original RGB files, too.
Thanks in large part to modern ICC color management, something Dan isn't at all very savvy in! Making outstanding output on a CMYK device is easy, once you have the proper ICC profile for the output.
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Ken Bennett

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Re: How to swap from DARKS to the Left to LIGHTS on the LEFT IN CS6 CURVES
« Reply #8 on: December 25, 2013, 02:04:47 pm »

Which is odd. CMYK is highly device dependant meaning, you need the specific and correct recipe for CMYK or you get butt ugly output.

Right on several counts. At that time the print shops never saw or worked with RGB files -- the scanners did an internal conversion to CMYK so the color imaging techs only ever saw CMYK data. But they could do amazing things with those files, even from other projects and different color houses. I was always amazed to see decent printed output from something I knew was scanned for a totally different project a year earlier.

(Of course all those scans were made to be 100% at the specified output size -- half page, quarter page, whatever, and sharpened on the fly during the CMYK conversion process. So the vast majority of a magazine's scans were at best 2x3 inches at 300ppi. I will never forget how many times my editor and various higher-ups told me to "save all the scans for re-use" and I would try to explain image size and pixel dimensions to no avail. Good times.)

The cool thing about using Margulis' system is that it almost always works. I could (and did, for kicks) color correct a photo on a black and white monitor, and get excellent results. Seriously. I could (and did, more times than I can count) color correct a turd image that we got from some law firm for use in the classnotes section, quickly, accurately, and easily. (Or, worse, a crappy, poorly exposed, 1-megapixel point-and-shoot image taken by a researcher that the designer wanted to spread across two pages.)

When we started shooting with digital cameras, some of our clients wanted to just provide the RGB files to the printers. This had mixed results :). I have stories :). Suffice it to say that since none of our print houses used any sort of color management for RGB files at that time, having that missing from the Margulis books was not a serious issue.
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kirkt

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Re: How to swap from DARKS to the Left to LIGHTS on the LEFT IN CS6 CURVES
« Reply #9 on: December 26, 2013, 12:27:33 pm »

While it is easy to malign Lab, and convert back and forth to RGB  ten times to show how much damage it does to a file, it is a much more intuitive way to think about color and contrast.  Even if you can do many of the color and contrast moves in Photoshop in RGB, it often helps to think about things in terms of Lab and the relationships between Lab and RGB.  Read the book and take a way from it what you will.  It is not the end all be all for everyday workflow, but it helps one to understand color and contrast.

If you are reading his most recent book, Lab aside, it emphasizes working quickly.  Very quickly. In a methodical way.  Many times I think one can get several minutes into editing a single image and lose perspective.  In contrast, the idea in the most recent Margulis book is to work quickly and decisively, making several versions of a image and thinking about what works and what does not  - often the final image is a blend the best of the results.   In spite of what one might think, much of the book is dedicated to RGB and enhancing contrast in the RGB channels.  This requires one to subscribe to the methodology espoused in the book, but even if you do not, you gain a much better understanding of how RGB channels capture and contain pertinent scene information for various types of scene lighting and content.  Again, it makes you think about the image and its foundation, instead of simply sliding a contrast and clarity slider around.

This is nothing novel, per se, about these image editing elements, but they are worth considering - especially when applications, like Lightroom, do much of the thinking for you and are self-contained editing and printing environments that encourage conforming to their structure and sliding sliders ad nauseum.  While it is interesting that Lightroom provides a method to make virtual copies of an image, ostensibly promoting variation, there is no way to combine these variations.  

And, as I'm sure you have already realized, just go to the curves window display options to change from Light to ink% to switch the direction of the curve axes, if that makes it easier to follow the book.

kirk
« Last Edit: December 26, 2013, 12:35:16 pm by kirkt »
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digitaldog

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Re: How to swap from DARKS to the Left to LIGHTS on the LEFT IN CS6 CURVES
« Reply #10 on: December 29, 2013, 09:36:06 am »

...it is a much more intuitive way to think about color and contrast.
Perhaps, that's up to the person looking into this. Everything you understand seems intuitive yet I know Photographers who's heads explode when presented CMYK and prepress folks who's heads explode with RGB. Lab IS an intresting color model but has plenty of warts and issues, it was never designed for image editing and in fact predates Photoshop by a very long time. If you find it intuitive and useful (and I do too), great. You can use the model without having to convert any data into Lab too. IF the OP is confused at this stage, I'd agree with him to move on. And while Dan does have some very useful techniques for fixing problems with rendered images, nearly all are unnecessary for the modern phtoographer working with RGB data and/raw. I also find his writing style rather difficult to get through but that's me. In the end, someone who's very savvy can correct images on a monochrome display using just numbers but why resort to working with one hand timed behind your back unless you are out to prove something. Work with a well calibrated and profiled display. Work with a good raw processor and well captured raw data. Make the image appear as you desire. You don't have to look at every image that has a scene with Cement and assume it should be neutral and do so (something Dan suggests). For him, the person who didn't make the image, it might be useful to make such assumptions. If you were the photographer and you know the image was shot at sunset, or you wish to invoke a look based on what you recall the image appearing as, none of these tricks are necessary. Make the image appear as you desire, soft proof, use sound color management and 90%+ of your color and tone issues are moot.
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