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andrew_rodney1

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Posts posted by andrew_rodney1

    dumb q about colour spaces/profiles etc

    in The Digital Darkroom: Process, Technique & Printing

    Posted

    Digital images represent color using big piles of numbers. That's all a computer can

    understand. When you Assign a profile to an image, you give the numbers a meaning (a

    scale). R255 doesn't tell us anything about color appearance but we can guess it's red. But

    how red? Unless we know the scale of the numbers, we can't reproduce it. R255 in Adobe

    RGB isn't the same as R255 in sRGB. When Photoshop see's R255 without a color space, it

    needs you to properly assign the color space so it knows the scale. That's all Assign Profile

    does.

     

    Read this: http://www.takegreatpictures.com/HOME/Columns/Digital_Photography/Details/params/object/9785/default.aspx

    Imacon Scanners

    in The Digital Darkroom: Process, Technique & Printing

    Posted

    They are fine products and worth the money if you're serious about high quality scans (the

    only thing superior would be a true PMT drum scanner). That said, I finally sold my 848

    last month because I simply wasn't using it and lusted after a Canon 5D (which is getting a

    lot more use). I still need a scanner for the 2 times a year it comes in handy. I'm looking at

    an Epson 750 but I want to wait until my bud Mac Holbert gets one to test and gives it a

    thumbs up. Even with oil mounting, I don't expect Imacon quality (the lens on the Imacon

    probably cost more than then several Epson scanners).

     

    When I was using my 848, I was very happy with the quality of the hardware, software and

    scans.

    Shooting in AdobeRGB. Any benefit?

    in The Digital Darkroom: Process, Technique & Printing

    Posted

    -->Bluntly stated...(Assumed that we are not in the art-reproduction business)...do we

    care about the 'ACTUAL' colors in a scene at the time of capture?

     

    You really can't be. It's important here to understand the very important difference in what

    is known as scene referred colorimetry and output referred colorimetry. I co- authored

    this piece with Jack Holms of HP (one of the top camera and color scientists there and on

    the ICC digital camera committee). I suggest you take a read (it's very light and not at all

    color geeky):

     

    http://www.color.org/ICC_white_paper_20_Digital_photography_color_management_basics.pdf

    Shooting in AdobeRGB. Any benefit?

    in The Digital Darkroom: Process, Technique & Printing

    Posted

    -->Question to you Rodney; When editing your images are you not come to a point that

    you are happy with what you see on your monitor screen?

     

    I'm not sure I follow you...

     

    We're talking about very saturated colors that fall outside display gamut. So I'm not seeing

    say a blue sky on screen that ends up printing too cyan or magenta on output. I'm seeing

    a more saturated blue I want on the print (as an example).

    Shooting in AdobeRGB. Any benefit?

    in The Digital Darkroom: Process, Technique & Printing

    Posted

    -->OK Andrew, I think I know now the differences and pro's and con's and all. Butt still I'm

    not utterly, utterly comfortable(yet) with editing colors in wider gamut colorspaces -

    knowing that they excist in that particular photograph - but my monitor can't display

    those colors, and furthermore I cannot accurately softproof.

     

    That's a viable concern and hopefully, we'll all be able to afford wider gamut displays (the

    technology is in it's infancy). Today, 99% of users are working with displays that can

    roughly produce sRGB. There are wide gamut displays but at a price (and they have issues

    too IF you're working with small gamut originals). Software will aid too. For example,

    Adobe kind of, sort of tried to address this in the Color Settings by providing the

    "Desaturate Monitor colors by" field. It's a kludge and I don't recommend it but there are

    those who feel that better software solutions that temporarily reduce the saturation so you

    can see the outward boundaries of a wide gamut color space as you edit are possible.

     

    But this isn't unique to gamut. Look at the soft proof and your print and you'll see that

    there are all kinds of areas of compromise. The dynamic range of the display versus the

    print can be pretty wide. This is why we have the Customize Proof setup options for paper

    white and ink black. In other words, not only is soft proofing an issue with wide gamut

    spaces, it's an issue when you have a big disconnect between the contrast ratio of the

    display versus the contrast ratio of you print. Yet we see more and more LCD

    manufacturers marketing wider contrast ratio's as a selling point (I personally think a great

    deal of this is total BS but you get the idea).

     

    Go back to film. It too has a gamut and contrast ratio that is quite different from a

    reflective print. That didn't stop us from making prints from film that we more or less

    agreed "matched" the original. It didn't but perceptually, we felt it did. In the end, we're

    almost always dealing with the issue of fitting square pegs in round holes. How many here

    remember shooting Polaroids and mentally adjusting what we saw to what we hoped to

    see on film?

     

    The bottom line is this. You can funnel all your files into the gamut of your display

    because you're concerned about a gamut mismatch, resulting in a great loss of color your

    output device CAN reproduce. Or you can contain the colors and output them but not see

    them. Given the options, I'd prefer to contain the colors and reproduce them, even if I can't

    totally see the all these colors on screen. It's not like those colors are radially different

    than what you'll output if all your color management ducks are in order. If the output

    meets your satisfaction but some real saturated colors don't look that saturated on screen,

    not a hill worth dieing on. And the lesson to be learned here is be gentle in corrections

    such as pushing Hue/Sat adjustments if you know the file has a lot of out of gamut colors

    on a lesser gamut display.

    Shooting in AdobeRGB. Any benefit?

    in The Digital Darkroom: Process, Technique & Printing

    Posted

    -->Why? What does it hurt to put everything in ProPhoto RGB for manipulating and then

    convert to sRGB for the web?

     

    You're not using your bits to the best use if you could encode into a smaller color space. If

    the scene can fit into something smaller, use it. Now if you're a bit lazy and you're always

    willing to encode in high bit, and the question is, is it better to encode smaller gamut

    captures into larger color spaces than the other way around (which does toss colors away),

    OK. But ACR and hopefully Lightroom and other RAW converters show you which working

    space is best suited for each image.

    Apple O/S vs Windows

    in The Digital Darkroom: Process, Technique & Printing

    Posted

    -->Andrew, I think you seem to be a color management specialist. I struggle keeping my

    current system consistant for color management. I think Microsoft as made big strides in

    the last version of Windows with color management. How would you compare that to OS/

    X?

     

    There's nothing really that unique in either OS. Apple has let the ball slip IMHO with the

    ColorSync utility in Tiger (it does all kinds of cool stuff that is mildly useful for anyone who

    wants to be a color geek) but its' not all that intuitive. What is interesting is stuff like Core

    Image and Quartz Filters which no one has done much with but the potential is there. As

    for a photographer who just wants to work in Photoshop and similar ICC aware

    applications, it is on parity for both platforms. There's some useful automation for color

    management in Tiger with either Applescripts or Automator. Again, how useful that is to

    any one user is hard to peg.

     

    We'll have to see what MS does in Vista. On paper, it's real interesting stuff but I have no

    idea if it will run as intended or not. The good news is MS is looking (finally) at color

    management at the OS level in a more robust way. However, will that break something in

    the Adobe suite? Only time will tell.

    Shooting in AdobeRGB. Any benefit?

    in The Digital Darkroom: Process, Technique & Printing

    Posted

    The big deal about a perceptually uniform color space (kind of like CIELAB) is that a move

    of equal value in any direction at any point within the color space produces a similar

    perceived change to the observer.

     

    The other advantage of a perceptually uniform color space like CIELAB is that it allows us

    to put a value on the difference between two colors as a human would perceive them. Just

    how close are these two similar colors? The result are the myriad of deltaE calculations

    that are somewhat useful for numerically defining the differences in colors as we perceive

    them.

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