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Photoshop Channel concepts: The Power of Ten

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  #41  
Old 05-23-2011, 09:14 AM
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Re: Photoshop Channel concepts: The Power of Ten

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Originally Posted by Richard_Lynch View Post
But again, why not just do it in RGB and save the trouble?
Amen to that!

I think some feel the more complicated, the more color model conversions, the better. KISS.
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  #42  
Old 05-23-2011, 10:42 AM
creativeretouch creativeretouch is offline
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Re: Photoshop Channel concepts: The Power of Ten

Approximately one year ago I have found these links:

http://www.broadhurst-family.co.uk/l...cobsladder.htm

http://www.broadhurst-family.co.uk/l...ore_detail.htm

interesting technique ...
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  #43  
Old 05-23-2011, 07:34 PM
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Re: Photoshop Channel concepts: The Power of Ten

Looks like Lee Varis is also a fan of the 10 channel approach. See:
http://blogs.adobe.com/jnack/2011/05....html#comments

Its a worthwhile video. I do question why the images he illustrates from raw are so under exposed (look at the histograms) or why he zero’s the ACR controls so much and ends up with a pretty butt ugly image before Photoshop is even used. Sure, the after looks better than the before (it better). But the before is very poorly rendered from raw (poorly exposed too). Why render a turd to polish in Photoshop so much. I suspect 90% of all this work could have been conducted in ACR first.

That said, Lee explains this technique far better and clearer than Dan M. There’s a lot of useful info in the presentation. I just think 75%+ is unnecessary if one captures and renders raw data appropriately.
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  #44  
Old 05-24-2011, 03:44 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
Its a worthwhile video. I do question why the images he illustrates from raw are so under exposed (look at the histograms) or why he zero’s the ACR controls so much and ends up with a pretty butt ugly image before Photoshop is even used. Sure, the after looks better than the before (it better). But the before is very poorly rendered from raw (poorly exposed too). Why render a turd to polish in Photoshop so much. I suspect 90% of all this work could have been conducted in ACR first.
I use same or similar technique to process my RAW files. Or let's say I underexpose my images already in my camera. I started to develop my own B&W images back in 1984. I learned how to use different developers in combination with different films & papers to achieve desired contrast of my images. Then I was pointed to Ansel Adam's "Zone System" technique which is based on combination of right exposure corrections + right film + right film developer + right paper developer + right paper ...

When I started to work with digital cameras (approximately in 1999) I released they are set up in "the wrong way" for my usual workflow. First thing what I use to do was to underexpose the image.

My first step in RAW processor is to take a look at color image as it would be B&W. Basically I judge the quality of "informations" within highlights and darks. I would make highlights less bright just to bring more informations to this part of image. And darks less black obviously. Then in Photoshop, I deal with luminosity & color separately.

I have a feeling that RAW processor does not deal with luminosity in the same way as I do in Photoshop. Within Photoshop I am able to work more precisely.
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  #45  
Old 05-24-2011, 08:34 AM
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Re: Photoshop Channel concepts: The Power of Ten

The last thing we want to do in digital capture is under expose the data. For those wondering why, see:

http://www.luminous-landscape.com/tu...se-right.shtml

http://www.digitalphotopro.com/techn...g-for-raw.html

When one examines Lee’s Red Church shot, one can see its quite under exposed (using the ETTR technique above, I suspect a good 2-3 stops under), with the current settings, and there’s a heck of a lot of noise in a capture from a good Nikon at ISO 100! Its flat and darn ugly. I’m amazed anyone would take such a poor rendering into Photoshop unless of course the goal is to show how a complex technique can make a poor quality capture look better. And if someone handed you that image as a TIFF, its a darn useful technique! But to do this on purpose from a raw capture is, well, very odd in my book.

I think I saw the church exposure as wide open, at ISO 100, at 1/6400th of a second. Again, odd. At the very least, based on the subject, it would have been mildly useful to bracket the exposure on the plus side (in this case via shutter) and produced a better quality raw to start with. Then use the converter to produce the best possible rendering quality considering the data provided, and then polish in Photoshop.
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  #46  
Old 05-24-2011, 08:55 AM
creativeretouch creativeretouch is offline
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Re: Photoshop Channel concepts: The Power of Ten

Andrew, perhaps you are right but I am happy with my technique and I like it as it is. And picture is noiseless ...

http://creativeretoucher.com/001.jpg
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  #47  
Old 05-24-2011, 09:52 AM
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Re: Photoshop Channel concepts: The Power of Ten

Just be aware that darker regions of digital images have more noise as fewer bits are used to describe the information. You should expose as bright as possible - without clipping any detail that you need in the highlights. This will give the least noise (and banding issues) when adjusting the image later on.

Anyway, back on topic, I do agree with Richard_Lynch and andrewrodney that (unless for some very special reason) it's best to keep your document in RGB. Learn how to use different types of layers and blending modes (like Color and Luminosity) and you suddenly have no real use for LAB and the problems that come with it. Note that converting between color spaces (and profiles) always gives you some information loss in the image (most notable with CMYK).

CMYK conversion is ideally done in the printer or RIP at the very end of the workflow and not something you should need to do manually to images (use Soft-Proofing instead if you need a preview). For example when working for print in InDesign I would link the original RGB images (properly tagged with their ICC profiles), and let the CMYK-conversion be done when generating the final PDF (this also allows me to output to different printers that use different profiles, or to cross-publish for screen without the color loss of CMYK).
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  #48  
Old 05-24-2011, 10:15 AM
creativeretouch creativeretouch is offline
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Re: Photoshop Channel concepts: The Power of Ten

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Originally Posted by Chain View Post
Just be aware that darker regions of digital images have more noise as fewer bits are used to describe the information. You should expose as bright as possible - without clipping any detail that you need in the highlights. This will give the least noise (and banding issues) when adjusting the image later on.
I do not think this is out off topic. I agree with you, Chain. You should expose as bright as possible. My picture above is a good example. if you aren't going to adjust your exposure, automatic setting on your camera will overexpose white buildings as this is the most contrast scene you will ever shoot. Direct & strongest sun, white buildings and most of the part of this image are darks or midtones. You need to make your choice - white, clipped buildings or small amount of noise in the shadows (which is not going to be seen on the final print anyway). If you would shoot on film - you will be facing same problem as well (film grain). And this is what Ansel Adams tried to explain ... (Zone System Theory).
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  #49  
Old 05-24-2011, 10:50 AM
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Re: Photoshop Channel concepts: The Power of Ten

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Originally Posted by creativeretouch View Post
Andrew, perhaps you are right but I am happy with my technique and I like it as it is. And picture is noiseless ...

http://creativeretoucher.com/001.jpg
I can’t (nor need) speak to noise in your image(s) but can to Lee’s shown in the video.

With linear capture, the bottom line is, less exposure equals more noise in shadows. That’s what ETTR is all about (idealized exposure). Especially at lower (native) ISO settings.
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  #50  
Old 05-25-2011, 03:51 AM
RobertAsh RobertAsh is offline
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Re: Photoshop Channel concepts: The Power of Ten

Hello Michael,

I see you're still the LabPirate, just in a different venue Really great to run into you here, missed you in the NAPP forum and wondered where you'd gone. I ran across RetouchPro some time ago (bought their main two retouching DVDs back when they were selling them). But I just joined RetouchPro forum earlier this month and it's quite a new level of expertise overall. Really great place!

Cheers, and look for me to bug you sometimes!
Robert
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