Any Minolta/Sony users using UFRaw and GIMP?

Discussion in 'Digital Cameras' started by Jeffery Small, Apr 5, 2014.

  1. Jeffery Small

    Savageduck Guest

    Oh Hell! If you look around this room you are going find all sorts of
    folks with firearms.
    < >

    ....and some of us actually know how to use them.
    < >
    Savageduck, Apr 20, 2014
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  2. Jeffery Small

    Sandman Guest

    No wonder, you're a typical troll.
    Sandman, Apr 20, 2014
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  3. Jeffery Small

    Sandman Guest

    No it isn't. Asking for substantiations for explicit claims is not a troll
    tactic, Eric.
    Classic troll diversion. It is obvious that I have said nothing about the
    purpose of nospam's "words" at all. I am merely correctly pointing out that
    you just confirmed that nospam had said nothing specific and that the troll
    in question had drawn a specific conclusion from it nonetheless.
    You are free to interprete as you please, but when you make explicit claims
    based on no explicit statements from someone else, then you will have to
    support your claim.
    Sandman, Apr 20, 2014
  4. Jeffery Small

    Eric Stevens Guest

    Eric Stevens, Apr 20, 2014
  5. Jeffery Small

    Sandman Guest

    No it isn't. Repeating it won't make it true. This is your claim:

    Eric Stevens
    Re: Any Minolta/Sony users using UFRaw and GIMP?
    04/17/2014 <>

    "That nospam claims this is evident from his writings."

    You're saying that it is evident from what nospam has written, that:

    1. It has improved his workflow 2. His workflow was previously

    If something is "evident" means that it is obvious that something is true -
    which is why I am asking you to substantiate the claim. You are claiming
    that something is obvious but fail to provide support for what makes it
    obvious. You are refering to a "nebulous" of statements that supposedly
    taken together makes it obvious that nospam regards his previous workflow
    as ineffective. I am asking you to put forth the material that made this
    obvious. Asking this of you is NOT a "troll tactic".

    Making a claim about another person without being able to support it, is a
    troll tactic, however.
    Which says nothing about the motive of nospam's words, just like I said.
    Of course I can. nospam has said "stuff", you have reached a conclusion
    from that "stuff" and I am asking you to support it. Just because I contend
    your conclusion does not mean I regard "stuff" as having no effect what so
    No, it's the other way around - you can't base your specific conclusion on
    unspecific words. That's the entire point. I am asking you to support
    something that you clearly can't support in an effort to make you realize
    that you can't support it and thus should retract your claim.
    Exactly. And you still don't get it.
    You should, yes.
    Sandman, Apr 20, 2014
  6. Jeffery Small

    Alan Browne Guest

    I have no definite answer - but consider that the way the information is
    stored in memory to work in Lab and RGB may be different and therefore
    require a conversion. If I load a really large raw (which then is shown
    to be 16 bit RGB) and then change it to Lab, there is "flash of change"
    in the image on the screen - as if it has been redrawn on the screen
    following a conversion.

    That could mean:
    1) The data was converted and then re-displayed from the converted data.

    a) convert the image RGB -> Lab, discard the RGB copy in memory
    b) display the image from Lab to the display
    c) image remains in memory as Lab


    2) The data was not converted, but was converted on the fly for the
    purpose of display only - the in-memory copy remains RGB.

    a) no conversion
    b) to display the image, point by point RGB is converted to
    Lab and then displayed from the Lab data and interpretation
    c) image remains in memory as RGB

    That said, the baseline internal representation might be Lab - so switch
    things around above as needed.

    Given 16 bit representation and the far less than 16 bit capability of
    our displays, prints/inks and eyes - in the end, for a typical amount of
    manipulation - and then some - there wouldn't be any discernible loss of
    information due to conversions IMO.

    All that said I don't see a huge advantage to working in Lab directly -
    though for some "effects" it presents an easy path to fun things. I've
    tried high pass sharpening in the mono channel in Lab, and while that
    works, the results are no better than high pass while in RGB. Any
    particular "betterness" at the pixel level don't show at the whole image
    level and are not at all perceptible in a print.
    Alan Browne, Apr 20, 2014
  7. Jeffery Small

    PeterN Guest

    On 4/19/2014 8:50 PM, Eric Stevens wrote:

    i use levels for that, one channel at a time. You can also get rid of
    haze selectively using a graduated mask. Make a selection, then:
    (select ! modify ! feather.

    You can also use this technique for blurring, etc. Yes I know ther are
    commercial presets for this, but This technique works for me.
    PeterN, Apr 20, 2014
  8. Jeffery Small

    Alan Browne Guest

    I just did this on a high key light image. See these 4 images.

    [1] Original (now in .jpf (JPEG2000) to save space) (aka: the Lab copy)

    [2 Original ( .jpg to save space) (aka: the RGB copy) copy copy.jpg

    [3] The difference (substraction - in jpg) (aka: nospam is wrong)

    [4] The difference (with sharpening on the Lab copy, jpg)
    (aka: test that difference works).


    -Image was loaded as raw and duplicated to a 2nd image.
    -First image was changed to Lab
    -First image was saved as TIFF (from Lab 'space') ([1] above)
    -2nd image was saved as TIFF (from RGB 'space') ([2] above)
    -Both images were re-loaded (they loaded as Lab and RGB - just as they
    were saved).
    -Copied the 2nd image and added it as a layer over the first.
    -Difference would not work when one layer was in Lab and the other in RGB.
    -Converted the first image back to RGB, then replaced the 2nd image as a
    layer again.

    *Difference was pure black (no differences - [3] above)

    -Sharpened the 2nd image to verify that differences would pop out (they
    did) and replaced the layer over the 1st image with it.
    *The sharpening difference showed ([4] above)

    So not only were the differences invisible to the eye they were NOT AT
    ALL shown by differencing.

    Of course you're welcome to show differently.
    Alan Browne, Apr 20, 2014
  9. Jeffery Small

    PeterN Guest

    Another really logical statement, without factual basis.
    PeterN, Apr 20, 2014
  10. Jeffery Small

    PeterN Guest

    You've said that before, and rceived a logical answer.
    do keep up
    PeterN, Apr 20, 2014
  11. Jeffery Small

    PeterN Guest

    the title of this thread is.......
    PeterN, Apr 20, 2014
  12. Jeffery Small

    Savageduck Guest

    All of these Dropbox url's are fractured and do not load, and are thus
    a PIA. Have you considered using limiters "< & >" or the DB link
    shortener (accessible via your page), or if that is too
    much, Tiny URL?
    < >
    Savageduck, Apr 20, 2014
  13. Jeffery Small

    Alan Browne Guest

    Alan Browne, Apr 20, 2014
  14. Jeffery Small

    Alan Browne Guest


    BTW I haven't seen your comments to my P-38 reply on single engine
    issues on alt.p.
    Alan Browne, Apr 20, 2014
  15. Jeffery Small

    PeterN Guest

    The only time you might see a difference would be if there were colors
    in the LAB spectrum that are not in the RGB spectrum, and those
    differences would rarely be noticable in a photograph.

    PeterN, Apr 20, 2014
  16. Jeffery Small

    Alan Browne Guest

    A good point - but nospam's contention is conversion differences.

    Let's color the situation. The files were taken from raw, reduced in
    size, saved as TIFF in each RGB and Lab. Re-loaded and compared
    (differenced). There is not a hint of delta. RGB Lab Diff
    Alan Browne, Apr 20, 2014
  17. Jeffery Small

    Eric Stevens Guest

    I think the key point is whether or not the data is ever stored in
    RGB. Everything I have read suggests the data is stored in
    device-independent form (which RGB is not) with various suggestions as
    to it being stored in XYZ or Lab. The book I quoted has it that the
    Photoshop ACE (Adobe Color Engine) uses Lab. I don't know whether the
    alternative ICM (Windows) or Colorsync (Apple) color engines do the
    same thing.
    Eric Stevens, Apr 20, 2014
  18. Jeffery Small

    Eric Stevens Guest

    That's an interesting experiment. It may be that the difference shown
    is not due to RGB vs Lab. I suspect you might get a similar result if
    you compare RGB-16 bit to RGB-8 bit (to RGB-32 bit) etc. i.e. the
    difference is an artifact of *any* transform.
    Eric Stevens, Apr 21, 2014
  19. Jeffery Small

    Eric Stevens Guest

    ... which seems to support the contention that they have been
    through an identical series of conversions, no matter what the working
    mode might be.
    Eric Stevens, Apr 21, 2014
  20. Jeffery Small

    PeterN Guest

    Saved as a tiff in LAB applied curves in LAB mode to try for dark shades
    that are not in the RGB spectrum and back to RGB.

    < test.tif>

    converted the above to RGB, to LAB & back to RGB, and back to LAB
    < test rgb.tif>

    Anyone can do their own subtractions.
    PeterN, Apr 21, 2014
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