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Image Processing and Workflow RAW, DNG , TIFF and JPG. From Capture to Ready for Publish/Display. All software and techniques used within an image workflow, (except extensive retouching and repair or DAM).

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  #31  
Old June 20th, 2006, 05:16 PM
Don Lashier Don Lashier is offline
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> I'm just wondering how much of a difference it is.

Not dramatic - you probably won't even notice it unless you're printing pictures of flowers or covettes, but quality is often made up of the sum of small differences and given that with properly setup workflow it's really no harder than working in sRGB, I switched to an Adobe RGB workflow quite a while ago even though I was a (former) skeptic also.

- DL
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  #32  
Old June 21st, 2006, 01:50 AM
Sean DeMerchant Sean DeMerchant is offline
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Quote:
Originally Posted by Wolfgang Borrs
I shoot RAWs in Adobe RGB for magazines.
I am editing my Images on a monitor only able to diplay sRGB, my question is now, is this a blind flight, am I working on colors which I can´t see? Wouldn´t it be better to shoot and work in sRGB, as long as I do not have an Adobe RGB Monitor.
Wolfgang
No, it is not a blind fight. The real value of a huge color space is that you can transform the image to retain image data in super-saturated tones in the smaller color space. We know that saturation will be lost in the output, but there is no good reason to lose detail too. This demarks the difference between a fine print and sloppy print IMO.
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  #33  
Old June 21st, 2006, 01:57 AM
Sean DeMerchant Sean DeMerchant is offline
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Quote:
Originally Posted by Tom Yi
Also, I may be wrong, but doesn't working in non sRGB color gamut a moot point unless your monitor can handle aRGB/pro photo and printer can print in those gamut as well?
Your working space (sRGB, Adobe RGB 1998, ProPhoto RGB, ...) are not directly related to your output color space. Working spaces are designed to make the underlying mathematical operations intuitive (i.e., R,G,B=27,27,27 is a dark gray rather than a dark color with a magenta hue).

What your monitor can display and what your printer can print are another issue. These are device spaces that describe what colors can be output by that device. These are not working spaces and in a device space 57,57,57 could be a dark magenta or a dark violet.

And I have never heard of a monitor that can display only the sRGB color space. I have heard of monitors that have psuedo sRGB calibration, but this is intended to allow the average user who cares little about results (i.e., not very picky) to get decent results from an uncalibrated workflow. This is good enough for a rather low standard of good enough.

Most printers ($100 US inkjets) can print many colors outside the sRGB gamut. Do you really want duller and flatter colors from a printer that can do more just because of your workflow?

some thoughts,

Sean
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  #34  
Old June 21st, 2006, 07:08 AM
Andrew Rodney Andrew Rodney is offline
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There are three areas where you need to look with respect to color gamut:

1. The gamut of the capture device. In reality, digital cameras and scanners don't have a gamut (they have what is called a color mixing function). None the less there is a gamut to film (which limits what the scanner produces). There's a real world of color gamut we see and it's pretty huge. Anytime you see one of those horseshoe plots of color (CIE chromaticity diagram), you're seeing the gamut of human vision. A digital camera can capture a huge range of color. All you need to do is take a RAW file of a very colorful scene in Adobe Camera RAW and examine it's Histogram for color clipping. I have tons of images that fall far outside Adobe RGB gamut. IF (big if) I want to contain the colors I shot, I need to use a much larger gamut like ProPhoto RGB (in 16-bit).

When you set your camera to sRGB or Adobe RGB (1998) and throw away the RAW file, you have no control over this. However, there's no question that selecting Adobe RGB will provide a larger gamut of captured colors compared to sRGB assuming the scene has a larger gamut than sRGB. That's pretty likely. Is capturing those important to you?

2. The gamut of the output device. You've decided that you do want to contain colors in the scene your capture device has collected. Now there's the gamut of the output device. Anyone that tells you "no output device exceeds sRGB" is smoking some very bad stuff or simply doesn't know what they are talking about. Again, by viewing a gamut plot (in 3D preferably), you can find all kinds of output devices that have colors that it can reproduce outside of sRGB. Are those color important to you? As I mentioned, the new K3 inkset from Epson produces colors that fall outside of Adobe RGB (1998)!

3. There's the gamut of your display. 99.9% of users have a gamut that's no larger than sRGB. There are new displays on the market that exceed Adobe RGB (1998) but at a huge cost (today). So there ARE colors you can capture and output you can't see on your sRGB display. The question becomes, do you throw away those colors you captured AND CAN reproduce away because you can't see them all? I think not but maybe some do.

This is all about flexibility and future output needs. IF you know that the scene gamut/camera can't exceed sRGB AND you know your printer can't produce anything larger than sRGB (get a new printer ), then sure, stick with sRGB. But if you look at just Epson and the evolution of increasing gamuts in ink technology, why paint yourself into a corner???

Those silly labs that tell you "just send is sRGB and all is well" are either lazy, don't understand color management or simply don't want YOU to decide how to handle YOUR files! There are NO printers on the planet that produce sRGB!!! The only sRGB device is a CRT display in a very fixed and defined environment. In fact sRGB is a totally synthetic color space designed using pure math (as are all the other RGB working spaces). These labs just don't want to profile their devices so you can soft proof the image, they don't want to worry about embedded profiles and want their automatic systems to simply assume all files are sRGB. Then they do a conversion to the printer color space on the fly. It makes them very productive. However, you lose a lot of control over how you render an image for an output device.
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  #35  
Old June 23rd, 2006, 03:30 PM
John_Schwaller John_Schwaller is offline
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What is wrong, if using ACR->CS2, to start with Raw and do all follow on PP in ProPhoto-16bit....and then convert to jpeg at the very end.....sRGB for web and ProPhoto-8bit for printing (using Qimage)?

My thoughts are it maintains the best space for all the processing steps and the initial jpeg (minimal compression) is more than just fine for printing. I do not believe TIFFs will give any better results.

John
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  #36  
Old June 23rd, 2006, 03:58 PM
Andrew Rodney Andrew Rodney is offline
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Nothing wrong (it's right!).
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  #37  
Old June 23rd, 2006, 06:11 PM
Bart_van_der_Wolf Bart_van_der_Wolf is offline
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Quote:
Originally Posted by John_Schwaller
What is wrong, if using ACR->CS2, to start with Raw and do all follow on PP in ProPhoto-16bit....and then convert to jpeg at the very end.....sRGB for web and ProPhoto-8bit for printing (using Qimage)?
Depending on your printer's (ink/paper) Profile, I'd prefer using a slightly smaller gamut colorspace than ProPhoto RGB for 8-bit/channel conversion. Profile conversions in 8-b/ch space may (depending on actual gamut differences, subject, and magnification) cause visible posterization.

You can test for that by assigning the ProPhoto RGB colorspace to this image, and converting it to the printer's profile. Just like in the RGB vs Lab conversions on that web page, you may or may not experience visible artifacting.

I never asked Mike Chaney whether Qimage, which is mainly an 8-b/ch application, uses dithering with profile conversions. If it does then there is a smaller chance of visible posterization.

Bart
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  #38  
Old June 26th, 2006, 08:44 AM
John_Schwaller John_Schwaller is offline
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Quote:
Originally Posted by Bart_van_der_Wolf
Depending on your printer's (ink/paper) Profile, I'd prefer using a slightly smaller gamut colorspace than ProPhoto RGB for 8-bit/channel conversion. Profile conversions in 8-b/ch space may (depending on actual gamut differences, subject, and magnification) cause visible posterization.

You can test for that by assigning the ProPhoto RGB colorspace to this image, and converting it to the printer's profile. Just like in the RGB vs Lab conversions on that web page, you may or may not experience visible artifacting.

I never asked Mike Chaney whether Qimage, which is mainly an 8-b/ch application, uses dithering with profile conversions. If it does then there is a smaller chance of visible posterization.

Bart
OK...I understand your concerns. I am not sure what Mike is doing either. I have read some posts of his (from about a year ago) where he is not high on the use of ProPhotoRGB, prefering aRGB or ddiRGB (which is not available in ACR). With ProphotoRGB to "printer profile" he mentions the possibility of banding with relative intent, but not perceptual. I am not sure if he was specific to the bit size in making that statement.

Assuming your concerns are valid, what would be your recommendation? Do all printing in TIFF? If so, what color space? If using jpeg for printing, would you recommend starting with aRGB direct from ACR or use ppRGB and at end convert to aRGB or ddiRGB (possible in PP??) before changing to 8-bit and jpeg?

Thanks for your advice....JOHN
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