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Photoshop Channel concepts: The Power of Ten

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  #71  
Old 05-26-2011, 01:19 AM
creativeretouch creativeretouch is offline
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Re: Photoshop Channel concepts: The Power of Ten

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Originally Posted by andrewrodney View Post
That may be true if all you have is an RGB doc but I think if the original is raw data, in a good converter, you’ll remove a great deal before you even render the data. Remember too that the noise is usually all in shadows. Raw is linear data and by the time its gamma encoded, a lot of damage is done. And if most shoot with noise in mind, exposing the data for ideal raw, not a JPEG, the noise would be far less (certainly when shooting at low/native ISO).
Yes, the noise is usually all in shadows. I see similarity to film grain here. If you compare film grain to digital noise - we can be really happy that the digital noise affect images less than film grain. I even agree to have most of the noise work done in the RAW converter. But if you shoot at low ISO the amount of the noise is so small that you don't need to care so much.
Some guys prefer to add small amount of noise back to the image before is printed (not for C-print of course)... And if you work at 300 Dpi - the noise should not be visible on the final print anyway.
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  #72  
Old 05-26-2011, 01:29 AM
creativeretouch creativeretouch is offline
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Re: Photoshop Channel concepts: The Power of Ten

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Originally Posted by RobertAsh View Post
Plus conceptually Lab's color model makes more sense to me than either RGB's or CMYK's. It's much more intuitive overall.

Over time I now mainly use RGB for portraits and Lab for landscapes/travel.
I agree ...

Regarding adjustment layers I have separate folders for each image. I name my files like 001_something_LAB and 002_something_RGB - the advantage of this is great. Even if you work with large files the file which is open is not so big and you do not have to have "a single room for RAM only" and strongest processor. I started to work on the computer with 64Mb of RAM and I can see now it was a great school
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  #73  
Old 05-26-2011, 02:28 AM
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Re: Photoshop Channel concepts: The Power of Ten

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Originally Posted by RobertAsh View Post
When I first got Margulis' book and started working in Lab I could do things I just couldn't do in RGB. That doesn't mean you or someone else couldn't do them, but I personally couldn't. Plus conceptually Lab's color model makes more sense to me than either RGB's or CMYK's. It's much more intuitive overall.
Lab does make a little more intuitive sense than RGB when it comes to thinking of brightness and color separately, but not as much as something like HSL. That's why I find it much more intuitive to work with Luminosity/Hue/Saturation as the color/brightness components of the image (Color = Hue + Saturation).

The fact that some people do not know how to do something in RGB, but know how to do it in LAB (e.g. sharpening the brightness and not the color), doesn't have to mean it is more cumbersome to do it in RGB. I think we will need a practical example here...
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  #74  
Old 05-26-2011, 08:43 AM
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Re: Photoshop Channel concepts: The Power of Ten

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Originally Posted by Chain View Post
Lab does make a little more intuitive sense than RGB when it comes to thinking of brightness and color separately, but not as much as something like HSL.
Agreed and fortunately we have this in ACR and Lightroom with very good controls.
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  #75  
Old 05-26-2011, 09:20 AM
RobertAsh RobertAsh is offline
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Re: Photoshop Channel concepts: The Power of Ten

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Originally Posted by creativeretouch View Post
I agree ...

Regarding adjustment layers I have separate folders for each image. I name my files like 001_something_LAB and 002_something_RGB - the advantage of this is great. Even if you work with large files the file which is open is not so big and you do not have to have "a single room for RAM only" and strongest processor. I started to work on the computer with 64Mb of RAM and I can see now it was a great school
That's a reasonable approach. I like it because it's easier to keep track of steps you took and to recreate those steps if needed. If you convert between color spaces you lose all that history as soon as you close the file unless you write out to a cryptic Photoshop trace file.

I've actually tried that approach before, and I ended up changing My_Image_RGB in one way, then changing My_Image_LAB in another way and found it impossible to keep both images in sync. I was learning the basics back then and did not have an established enough workflow to do that.

Over time I developed a workflow that is more organized and step-wise, but I still today get "aha" insights where I have to undo lots of steps or do a step that requires (for me) switching color spaces. So syncronizing the two color space copies is something I've pretty much given up on for now even though I still like the idea.....
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  #76  
Old 05-26-2011, 09:31 AM
RobertAsh RobertAsh is offline
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Re: Photoshop Channel concepts: The Power of Ten

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Originally Posted by Chain View Post
Lab does make a little more intuitive sense than RGB when it comes to thinking of brightness and color separately, but not as much as something like HSL. That's why I find it much more intuitive to work with Luminosity/Hue/Saturation as the color/brightness components of the image (Color = Hue + Saturation).

The fact that some people do not know how to do something in RGB, but know how to do it in LAB (e.g. sharpening the brightness and not the color), doesn't have to mean it is more cumbersome to do it in RGB. I think we will need a practical example here...
Yes, that would be helpful.

Part of it for me is forward thinking vs. reverse thinking, for lack of better terms. In Lab, if I want to increase or decrease Magenta or Blue or Lightness I just move the curves. For Red, I move Magenta and Yellow.

In RGB if I want to increase Cyan I have to decrease the Red curve. To be honest, that part just clicked the other day watching Ctein, before then it was really confusing conceptually, had no idea how to do that.

But in RGB that also changes brightness. To be truthful, since Lightness/Brightness is part of any color, it works about the same in Lab, but it's noticeably more controllable and has less drastic impact on the colors.

Another factor for me is that I'm still refining my color sense, i.e., the ability to look at an image and notice a slight color cast. Or, even more difficult for me, to look at a skin tone, see that it's "off" and see what combination of R,G,B will make it look natural. That's the hardest challenge I face regularly.

Lab makes correcting color casts easier, but for me it's often still a challenge to know what colors will get rid of "color cast X".

Quote:
Originally Posted by andrewrodney View Post
Agreed and fortunately we have this in ACR and Lightroom with very good controls.
Good point. I'd meant to mention that as well but my note was getting too long already

ACR and Lightroom aren't always there to the degree Photoshop is, but they do a good job most of the time and the great thing about them is you don't have to think about color spaces at all, just move one of those 10 sliders
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  #77  
Old 05-26-2011, 09:35 AM
creativeretouch creativeretouch is offline
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Re: Photoshop Channel concepts: The Power of Ten

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Originally Posted by RobertAsh View Post
That's a reasonable approach. I like it because it's easier to keep track of steps you took and to recreate those steps if needed. If you convert between color spaces you lose all that history as soon as you close the file unless you write out to a cryptic Photoshop trace file.

I've actually tried that approach before, and I ended up changing My_Image_RGB in one way, then changing My_Image_LAB in another way and found it impossible to keep both images in sync. I was learning the basics back then and did not have an established enough workflow to do that.

Over time I developed a workflow that is more organized and step-wise, but I still today get "aha" insights where I have to undo lots of steps or do a step that requires (for me) switching color spaces. So syncronizing the two color space copies is something I've pretty much given up on for now even though I still like the idea.....
I have my workflow written and usually I continue 03... 04 ... 05... - again, it depends on the work I am doing. It means, if I would go for "a new look," I would experiment and when I would be happy with the result I would write down all steps and follow them ...

If I would do "a fast" work, less important, I would flatten image and convert to the other color space without keeping a track of it.
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  #78  
Old 05-26-2011, 11:03 AM
creativeretouch creativeretouch is offline
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Re: Photoshop Channel concepts: The Power of Ten

OK. I just finished a quick test. I took RAW image (same as I posted earlier) and I exported it from ACR (Photoshop CS3).

http://creativeretoucher.com/002.jpg

Top image - ACR export without touching Photoshop (no sharpening, no lens correction, no retouching - I paid attention to luminosity/contrast & color only)

Bottom image (detail from the posted one) - low contrast export to Photoshop without any or little correction in the RAW converter (RPP) + many magics within Photoshop. (I did not work in LAB this time).

I am looking forward to hear your comments. Please imagine you will print this image in large size & hang it on the wall. So every small detail matter (luminosity/contrast & color).
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  #79  
Old 05-26-2011, 11:40 AM
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Re: Photoshop Channel concepts: The Power of Ten

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Originally Posted by creativeretouch View Post
OK. I just finished a quick test. I took RAW image (same as I posted earlier) and I exported it from ACR (Photoshop CS3).
Oh, that’s a real old version of ACR (you don’t have access to Process 2010 which is HUGE). Might want to download a demo of Lightroom 3, you have 30 days to play and the most recent raw processing engine.

Quote:
I am looking forward to hear your comments. Please imagine you will print this image in large size & hang it on the wall. So every small detail matter (luminosity/contrast & color).
That’s tough because its your image. The differences here are more about which one would prefer in terms of pleasing rendering; the Ektachrome or Velvia ‘look’. IOW, neither is problematic. Personally I think the bottom is a bit much in terms of saturation, the top needs a bit more pop. I’d split the difference but its not my image, I wasn’t there to shoot it, I can’t comment on what you are trying to express photographically.

The question I’d also ask is, why limit the raw rendering to only luminosity and contrast?

Its also a low rez web image so commenting about detail is moot.
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  #80  
Old 05-26-2011, 11:49 AM
creativeretouch creativeretouch is offline
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Re: Photoshop Channel concepts: The Power of Ten

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Originally Posted by andrewrodney View Post
Oh, that’s a real old version of ACR (you don’t have access to Process 2010 which is HUGE). Might want to download a demo of Lightroom 3, you have 30 days to play and the most recent raw processing engine.
Approximately two months ago I downloaded all most important raw converters to make my own tests & compare them.

Quote:
Originally Posted by andrewrodney View Post
The question I’d also ask is, why limit the raw rendering to only luminosity and contrast?
Obviously I would do it. It was just a test and I did not wanted to waste my time as those corrections are not important - regarding this test.

Even at this resolution you should be able to see difference.
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