PhotoSlop Compared to 4 Different Editors

Discussion in 'Digital SLR' started by Too Funny, Feb 7, 2010.

  1. Too Funny

    Too Funny Guest

    [corrected URL]

    I thought it would be fun to add yet one more graphic editor into the
    testing results, and then combine them all into one easy to see chart so
    people don't have to bother clicking on 5 different links. Then trying to
    remember what you saw at each one (I know how slow some of you are).

    "Granger Calibration Chart" Editor-Test Results

    Isn't this fun? :)
    Too Funny, Feb 7, 2010
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  2. You can add this one I just created with GIMP. GIMP doesn't have
    "Luminance" in its layer mixers, but applying "Hard Light" to the second
    gradient seems to produce the same effect.

    I also don't understand why the Luminance Landscape author says that the
    background color must be white. The background will be gone after applying
    the rainbow gradient anyway.

    Ofcourse, it would be nice to see a response by a PS-user, who can say if
    the error really is created by PS instead of the original author. I've
    seen more stupid errors from LL before.
    Robert Spanjaard, Feb 7, 2010
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  3. Too Funny

    Too Funny Guest


    Yes, I had to use that same "Hard Light" layer-blend option in one of the
    editors, I think it was in PhotoImpact. And another even more inexpensive
    and obscure editor worked the same (PhotoScape? or something like that),
    but the chart looked a little too different from the others to include it,
    it was using some "Legacy Hard Light" method or something that clipped all
    the blacks and lights. But even then the colors in that program, like
    yours, were a nice even spread without all those horrendous hills and
    valleys of the PhotoSlop one.
    Not sure why. It could depend on if they have their system set to create
    layers with a default transparency? Perhaps an easier way to circumvent
    other settings. In either case, that's not even 1/10th his problem. :)
    When I spotted the difference on that page I got curious. That's why I
    created that PhotoSlop Granger Chart on the comparison list I posted using
    my own copy of PhotoSlop to see if he made any errors. He did not. I even
    tried changing the system color profiles in PhotoSlop. I changed the
    "rainbow gradient" to the true colors that they should be (they are way off
    in PhotoSlop). They should be, from left to right, in 100% saturations:

    Red, Magenta, Blue, Cyan, Green, Yellow, Red

    At spacing increments of

    0%, 16%, 33% 50%, 66%, 83%, 100%

    Or if using hue-rotation degrees, then:

    0, 60, 120, 180, 240, 300, 360

    PhotoSlop's default "rainbow" gradient was all over the map in colors and
    spacing. Further adding to any PhotoSlop user's nightmare when using this
    method without correcting the gradient first. When I corrected PhotoSlop's
    gradient even that didn't help. It resulted in a similar mess as what you
    see in the above chart.
    Too Funny, Feb 7, 2010
  4. Too Funny

    Too Funny Guest

    How can you find dead or blocked areas that don't exist on the PhotoSlop
    Granger Chart?

    [now waiting for that cartoonist's light-bulb to get drawn in above your
    Too Funny, Feb 7, 2010
  5. But is it? It this chart the correct result of combining two simple
    gradient layers? Does that mean that the error is in _all_ the other
    That is the purpose of the Granger chart, and ofcourse I don't care how
    that chart looks at all. But if I was a PS user, I'd be very worried about
    the way PS combines two simple layers. That _does_ affect the end result.
    Robert Spanjaard, Feb 7, 2010
  6. Havve you tried other blending modes in PS? Perhaps this is just the way
    their Luminance blend is supposed to work.
    If I convert my own chart to grayscale based on luminosity, I don't get an
    even black to white gradient (which I do get with a Lightness grayscale).

    So apparently a luminosity blend is different from a hard light blend. But
    if I convert the PS version to grayscale based on luminosity, I also don't
    get a correct black to white gradient.
    Robert Spanjaard, Feb 7, 2010
  7. Too Funny

    Too Funny Guest

    I added yours to the comparison chart. Thanks. Had to change the
    perspective a little to fit but that doesn't change the overall appearance.

    Here's the link to the more complete version.

    There's room on that for 2 more editors now. Anyone else want to add their
    favorite editor that's not already represented on it? :)
    Too Funny, Feb 7, 2010
  8. Too Funny

    Too Funny Guest

    Good thinkin'! I just tried using the Hard Light blend using PhotoSlop, and
    it does indeed appear to work, most of the evidence of those grossly huge
    valleys and peaks disappears. But the results look like crap. All the
    colors are dulled and shifted. So does this mean they don't even know what
    "Luminance" means and all the other programs do? :) Would this also
    explain why most all photos posted to the net by PhotoSlop users are so
    grossly oversaturated because they have to over-compensate for each photo's
    saturation on their own screen?
    Too Funny, Feb 7, 2010
  9. Too Funny

    Paul Furman Guest

    Screen mode gives a symmetrical chart across the colors, as well as some
    other modes, hard light is similar. Immediately after choosing a mode,
    hit the up/down arrow keys. Not sure why luminosity works differently in
    other programs to the PS luminosity mode but as Alan said, it's still
    useful for their purposes or they wouldn't have put it out there,

    Luminosity means apply the lightness/darkness to the colors, and it's
    apparently counting the luminosity of the rainbow layer also, so the
    dark blues move down & the light yellows move up. This is the same sort
    of issue where you have to be careful what method you use for converting
    to b&w.
    Paul Furman, Feb 7, 2010
  10. Too Funny

    Too Funny Guest

    I guess this means anytime someone is using a lighten or darken
    (dodge/burn) brush in PhotoSlop or creating any changes in luminosity, like
    trying to recover details from shadows or highlights, they can expect all
    their colors to get shifted just as badly. Nice! :)

    A good thing my copy was given to me or I wouldn't spend one cent on
    something like this. The *ONLY* reason I even keep it on a computer at all
    is for the one or two worthwhile plugins that are PhotoSlop dependent. Soon
    as I use it for that plugin's effect and am done, it's shut down again with
    the hopes that I don't have to ever run it again too soon. There's far too
    many better programs out there than having to put up with its nonsense.
    Too Funny, Feb 7, 2010
  11. Too Funny

    Paul Furman Guest

    No, the burn & dodge tools work fine on the rainbow layer. It is an odd
    behavior though. I sometimes use luminosity mode on adjustment layers,
    rather than going to lab mode so that contrast/levels/curves adjustments
    don't effect saturation. Hmm, so yeah this does make a difference. If I
    try the granger thing in lab mode (set lab before adding layers) that
    makes a very different chart with much softer transitions like the gamut
    chart they describe in the LL article. Do these other programs have lab
    mode? CMYK mode produces yet another different effect.

    I checked adjustment layers on a couple normal photos, one with oranges,
    one with orages & blues, both have green backgrounds. Lab vs
    luminosity-mode adj layers had very slight color shifts making the
    yellows brighter, no effect on the blues. Normal mode made the
    saturation increase and orange showed more effect. So anyways, yeah, it
    does seem to be a bit of a problem but if you don't like the color
    shift, add another adjustment layer or use another program if you like.
    I've been using photoshop for 20 years so it's what I like working with
    and it has a whole lot of tools for whatever needs to be done.

    Photoshop is not the tool for scientific experiments & measurement.
    Roger Clark found some weird rounding errors & bit depth issues when
    using it to make extreme adjustments to shadow detail in raw
    conversions. I forget what program he used instead, something designed
    for astrophotography manipulations I think. Not the sort of program I'd
    like to use for general photo editing.

    These days I mostly use Lightroom for tweaking exposures, contrast etc,
    which also is not perfect but it's great for workflow. If I'm actually
    going to do a large print of a difficult subject, I'll take the raw file
    into my old-ish version of photoshop & do fussy stuff like sharpen a
    luminosity layer, etc. Otherwise I don't use photoshop unless I need to
    do some serious cloning or editing like that. Lightroom is quick and
    effective, letting me concentrate on what's important. If a contrast
    adjustment increases saturation, I'll just tweak the saturation slider.
    If the oranges pop, I'll tune that, etc.
    Paul Furman, Feb 7, 2010
  12. Too Funny

    Me Guest

    I can't cross-post (because of limitations of my free news server).
    The individual Photoshop (greyscale & spectrum) gradients might
    superficially look linear, but they are in fact not:
    Linear gradients produced by Gimp are on the left.
    Presumably there's a reason why PS does it this way, but I don't know
    what it is. Perhaps it's applying something like a gamma curve to
    gradients so that if they are used to blend down layers, the effect is
    visually more linear than a linear curve. (sounds like double-dutch - I
    Anyway, I'm at a loss to know how useful a "granger chart" can really be
    for system calibration for colour photography, except to demonstrate
    limitations (gamut) from various photo print processes. In that case
    it's better perhaps to use a colour chart / sample image with a
    distribution of colours which might be found in an actual photographic
    subject, rather than an artificial spectrum.
    Use a (good) granger chart, and soft-proof in photoshop using various
    ICC profiles including from systems claimed to "exceed sRGB gamut" etc,
    and you'll perhaps see what I mean.
    Me, Feb 7, 2010
  13. Too Funny

    Paul Furman Guest

    Over my head
    ....but that got me thinking about lab color space and there's some
    interesting similar issues involved there:

    In any case, I reproduced the chart like the others using two blending
    modes, patched together:
    see the other similarly named thread for that discussion.

    Each of the blending modes does a different calculation like your
    formulas. You can see a few different approaches in adjacent pics at
    that link, including lab mode.
    Paul Furman, Feb 8, 2010
  14. Too Funny

    Paul Furman Guest

    Paul Furman, Feb 8, 2010
  15. I am going to jump into this discussion with an idea, not based upon any
    direct knowledge I have as to why Photoshop is designed as it is, but
    with a mind toward human vision.

    Human vision is not linear at all. We see by two structures, rods, which
    perceive luminosity without color, and cones, three forms of which each
    see a different light frequency range, the "red" cones actually peak at
    yellow, green cones peak at green and blue cones peak in the violet part
    of the spectrum. These structures are not evenly distributed in terms
    of numbers or locations. Rods are more concentrated at the edges of our
    retina and are used in our peripheral vision, which has poor color
    vision. Cones are more concentrated in the middle of the retina.

    While the percentages of the three cone cells vary considerably between
    adults, thus creating the various levels and forms of color blindness,
    overall adults have very poor blue-violet color perception. We are born
    with less blue cones than either the red or green. Early in life,some
    are destroyed by UV light entering the eye. The UV also damages the
    transparent and neutral lens of the eye, slowly yellowing it until it is
    almost orange juice color as we pass middle age. While this yellowing
    actually filters the UV light reaching the retina, and therefore
    protects the blue cones left, it also filters out a huge amount of the
    blue light that reaches the retina, so a mixture of low blue cones to
    begin with, damage by UV early in life, and then a fairly heavy yellow
    orange filtration, means our blue perception stinks.

    While we are very attentive to reds, due to the evolutionary
    significance of red to yellow, it is the second smallest number of
    cones. So, while we are more aware of reds, we actually have less red
    cones to see it with. Our largest number of cones are greens, in most
    people by a substantial amount. This allows us to see green
    differentials quite well, and is probably significant because vegetation
    coloration can be important to survival.

    Now, I'm not sure what Photoshop is up to with their Granger Calibration
    Chart differences (yet at least - I've asked a friend who is a color
    engineer if he had any comments) but as someone who has a background
    with the human side of color perception, it may be that Adobe has made
    some accommodation for the species who use their programs, with our
    non-linear color perception.


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    Arthur Entlich, Feb 8, 2010
  16. Too Funny

    Paul Furman Guest

    Oh, I see what you mean. The odd looking asymmetrical PS version, if
    converted to grayscale, goes to a perfect gradient black on bottom,
    white on top. The others show dark & light vertical shapes like the
    color version. BTW I did a version in lab mode and had to convert to RGB
    for web... that rgb version looks very similar but doesn't go back to a
    smooth gradient but if I flatten the psd and convert that to grayscale
    while still in lab, it works. The lab version takes out the weird
    angular components, apparently lab is designed to transition more
    smoothly & match human vision better.

    None of these gives the appearance of a 'true' parallel set of vertical
    rainbow bands fading from black to white which one might expect from the
    exercise. Optics can be similarly baffling where you correct for
    spherical aberration, certain kinds of chromatic aberrations get worse
    or the bokeh goes ugly, etc.
    Paul Furman, Feb 8, 2010
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