Margulis LAB Color Book - Reading group

1246

Comments

  • aphotojaphotoj Beginner grinner Posts: 2Registered Users Beginner grinner
    edited February 2, 2006
    Prof Photoshop 4th edition
    rutt wrote:
    I have in mind to have another reading group for the new edition of Professional Photoshop, which Dan is sure will be out this year.

    I the mean time, don't be afraid to post questions. Some of us do know the current edition of Professional Photoshop pretty well.
    Was a reading group ever established for this book? I just got it, and am trying to work my way through it. I think I understand the theory in the first two chapters, but for the life of me can not apply it. I have no earthly idea how Dan is moving the curves around. Obviously, I missing something.

    After I convert my image to CMYK, I can not lay points down on the curve by Cmd clicking. Also, I want to use an adjustment layer, but when I do that, I can't lay points down either because it's sampling from the layer and not the background.
  • DavidTODavidTO Mod Emeritus Posts: 19,160Administrators moderator
    edited February 2, 2006
    aphotoj wrote:
    Was a reading group ever established for this book?


    Yep. Read the first post in this thread. There's a link for each chapter discussion posted thus far.
    Moderator Emeritus
    Dgrin FAQ | Me | Workshops
  • ruttrutt Cave canem! Posts: 6,511Registered Users Major grins
    edited February 2, 2006
    DavidTO wrote:
    Yep. Read the first post in this thread. There's a link for each chapter discussion posted thus far.

    David, I think he's talking about Professional Photoshop, not Photoshop LAB Color.... There is reading group for the LAB book and David's right: look at the first post in this thread.

    There is no reading group PP. I'd like to have one, but I'm waiting for a new, drastically revised, edition due by the end of the year.

    If I were you, I'd read the LAB book now and wait for the new PP.
    If not now, when?
  • DavidTODavidTO Mod Emeritus Posts: 19,160Administrators moderator
    edited February 2, 2006
    rutt wrote:
    David, I think he's talking about Professional Photoshop, not Photoshop LAB Color.... There is reading group for the LAB book and David's right: look at the first post in this thread.

    There is no reading group PP. I'd like to have one, but I'm waiting for a new, drastically revised, edition due by the end of the year.

    If I were you, I'd read the LAB book now and wait for the new PP.


    Oh.
    Moderator Emeritus
    Dgrin FAQ | Me | Workshops
  • aphotojaphotoj Beginner grinner Posts: 2Registered Users Beginner grinner
    edited February 2, 2006
    rutt wrote:
    David, I think he's talking about Professional Photoshop, not Photoshop LAB Color.... There is reading group for the LAB book and David's right: look at the first post in this thread.

    There is no reading group PP. I'd like to have one, but I'm waiting for a new, drastically revised, edition due by the end of the year.

    If I were you, I'd read the LAB book now and wait for the new PP.

    Well, oops, just bought the PP 4th edition, so I'm not likely to get a new one this year...I can sit and read the LAB book at B&N but will I be jumping ahead.

    BTW, I am distinctly female. ; )
  • DavidTODavidTO Mod Emeritus Posts: 19,160Administrators moderator
    edited February 2, 2006
    aphotoj wrote:
    BTW, I am distinctly female. ; )


    clap.gif
    Moderator Emeritus
    Dgrin FAQ | Me | Workshops
  • billcbillc Beginner grinner Posts: 1Registered Users Beginner grinner
    edited April 9, 2006
    How much
    Thank you for hosting and parsing Photoshop Lab Color.
    Question: Assume a Nikon .nef raw file. How much processing do you do in Bridge before transferring the image to Photoshop and using the LAB workflow? How does bridge, if at all, figure into the Lab raw workflow?

    To date I have been following the guidelines of Bruce Fraser (Camera Raw with Adobe Photoshop CS2) in dealing with raw images..

    Thank you for your assistance.
    BillC
  • DevinDevin Devin Posts: 1Registered Users Beginner grinner
    edited April 19, 2006
    Hi Rutt and everyone! I just bought a copy of the "Photoshop LAB Color" book and I'm currently reading it. I just stumbled across your thread and I think it's an excellent idea to have our discussion for each chapters based on the summary assigned to a certain person.

    I am curious if anyone is working on the summary for the following chapters:

    10 - TBD
    11 - Pathfinder?
    15 - TBD

    Thanks!

    Devin
  • GonzoBernelliGonzoBernelli Big grins Posts: 62Registered Users Big grins
    edited April 20, 2006
    Totally fascinated with "Conundrum" ...
    ...but I am a total NOOB to CS2 and LAB, having just migrated from PSE3, so I am limiting myself to the contents of the first 4 or 5 chapters....

    I send DM an e-mail last evening asking how to get the triple curves window (see bottom of page 7 in "Conundrum"). If this is available in CS2, how to get it? Or is it part of some plug-in? Or it is something hacked into existence by Dan? Or is it just some fancy "chopping" just for the printed volume?
    DISCLAIMER: This post is a natural product made from recycled electrons. The slight variations in spelling and grammar enhance its individual character and beauty and in no way are to be considered flaws or defects.
  • Mike LaneMike Lane I � Unicode Posts: 7,106Registered Users Major grins
    edited April 20, 2006
    ...but I am a total NOOB to CS2 and LAB, having just migrated from PSE3, so I am limiting myself to the contents of the first 4 or 5 chapters....

    I send DM an e-mail last evening asking how to get the triple curves window (see bottom of page 7 in "Conundrum"). If this is available in CS2, how to get it? Or is it part of some plug-in? Or it is something hacked into existence by Dan? Or is it just some fancy "chopping" just for the printed volume?

    Just fancy screen grabbing methinks. But damn, it would be handy to have all 3 of them show up with the little reminder color blocks wouldn't it???
    Y'all don't want to hear me, you just want to dance.

    http://photos.mikelanestudios.com/
  • DavidTODavidTO Mod Emeritus Posts: 19,160Administrators moderator
    edited April 20, 2006
    Mike Lane wrote:
    Just fancy screen grabbing methinks. But damn, it would be handy to have all 3 of them show up with the little reminder color blocks wouldn't it???


    They have those reminders in blend options...yeah, it would be nice in curves, too. Wouldn't make sense in RGB, but in LAB it'd be nice.
    Moderator Emeritus
    Dgrin FAQ | Me | Workshops
  • pathfinderpathfinder Drive By Digital Shooter western IndianaPosts: 14,182Super Moderators moderator
    edited April 20, 2006
    Devin wrote:
    Hi Rutt and everyone! I just bought a copy of the "Photoshop LAB Color" book and I'm currently reading it. I just stumbled across your thread and I think it's an excellent idea to have our discussion for each chapters based on the summary assigned to a certain person.

    I am curious if anyone is working on the summary for the following chapters:

    10 - TBD
    11 - Pathfinder?
    15 - TBD

    Thanks!

    Devin

    Chapter 11 is here - http://www.dgrin.com/showthread.php?t=29980
    Pathfinder - www.pathfinder.smugmug.com

    Moderator of the Technique Forum and Finishing School on Dgrin
  • bbushebbushe Beginner grinner Posts: 1Registered Users Beginner grinner
    edited July 6, 2006
    well, I read all your threads while waiting for the book to ship from the states. Obviously a lot of time and work has been spent in creating the chapter summaries, and I thank you all for sharing your work. This forum looks like a total treasure trove of ideas and knowledge!

    regards,

    bb
  • BinaryFxBinaryFx Major grins Posts: 707Registered Users Major grins
    edited July 22, 2006
    Mike Lane wrote:
    Just fancy screen grabbing methinks. But damn, it would be handy to have all 3 of them show up with the little reminder color blocks wouldn't it???

    Hi Mike, if you are a MS Win OS user - then there is a plug for Photoshop that will do that and more:

    http://www.curvemeister.com/

    I was a beta tester and feature request contributor for the v1 release, but that is my only professional affliliation with this vendor - this is intended as a public service message (the SW author is a fellow member of Dan's Applied Color Theory list).

    Regards,

    Stephen Marsh
    members.ozemail.com.au/~binaryfx
  • Mike LaneMike Lane I � Unicode Posts: 7,106Registered Users Major grins
    edited July 22, 2006
    That looks interesting but yeesh it's $80! :nah
    Y'all don't want to hear me, you just want to dance.

    http://photos.mikelanestudios.com/
  • BinaryFxBinaryFx Major grins Posts: 707Registered Users Major grins
    edited July 23, 2006
    Mike Lane wrote:
    That looks interesting but yeesh it's $80! :nah

    Hi again Mike, yes, a little pricey...I guess it depends how much you use curves and different colour spaces. It is the only method I know that allows one to view and edit all the curves for separate channels at the same time. Perhaps if there was competition, the price would drop.

    The links page at my website has some links to curves tutorials and tips:

    http://members.ozemail.com.au/~binaryfx/

    Best,

    Stephen Marsh.
  • hayzenhayzen Beginner grinner Posts: 1Registered Users Beginner grinner
    edited September 12, 2006
    LAB is a great way to enhance your photos.

    Does anyone know if they can use this same LAB technique in other Adobe products like After Effects to enhance their videos? If not, at least a similar way?
  • Tom K.Tom K. I post, therefore I am. Posts: 817Registered Users Major grins
    edited September 15, 2006
    I LOVE using LAB and this thread is phenomenal from top to bottom.

    The only problem that I have using LAB on my photos right now is that the Reds frequently get so over-amplified that they can destroy a photo. For example I took a photo and there was a red ice chest in the background. It turned a radioactive red and I had to mask out that color because it stood out like a sore thumb.

    How can I eliminate this Red overkill problem. If you fine folks can solve this one for me then I'll be one very appreciative and happy camper.

    Thanks again for such a fine thread.
    Visit My Web Site ~ http://www.tomkaszuba.com/
  • DavidTODavidTO Mod Emeritus Posts: 19,160Administrators moderator
    edited September 15, 2006
    Tom K. wrote:
    I LOVE using LAB and this thread is phenomenal from top to bottom.

    The only problem that I have using LAB on my photos right now is that the Reds frequently get so over-amplified that they can destroy a photo. For example I took a photo and there was a red ice chest in the background. It turned a radioactive red and I had to mask out that color because it stood out like a sore thumb.

    How can I eliminate this Red overkill problem. If you fine folks can solve this one for me then I'll be one very appreciative and happy camper.

    Thanks again for such a fine thread.


    Can you post a sample and let us know what steps you took to get there?
    Moderator Emeritus
    Dgrin FAQ | Me | Workshops
  • pathfinderpathfinder Drive By Digital Shooter western IndianaPosts: 14,182Super Moderators moderator
    edited September 15, 2006
    Tom K,

    The ability of LAB to cause radioactive colors is feature, not a defect:): mwink.gif

    Use LAB color enhancement within an Adjustment Layer, and then adjust the opacity slider to modify the intense colors back to a more preferable level.

    The Blend IF sliders can be used to limit the effect to just the magentas and avoid the greens or vice versa in the a channel, or the yellow or blues in the b channel. Or the Lightness channel can be used to select only the lighter or darker portions of the image as well.


    [imgl]http://Pathfinder.smugmug.com/photos/39902855-M.jpg[/imgl][imgr]http://Pathfinder.smugmug.com/photos/40008515-M.jpg[/imgr]
    Pathfinder - www.pathfinder.smugmug.com

    Moderator of the Technique Forum and Finishing School on Dgrin
  • jfriendjfriend Scripting dude-volunteer Posts: 24,828Registered Users Major grins
    edited September 15, 2006
    Three options
    Tom K. wrote:
    I LOVE using LAB and this thread is phenomenal from top to bottom.

    The only problem that I have using LAB on my photos right now is that the Reds frequently get so over-amplified that they can destroy a photo. For example I took a photo and there was a red ice chest in the background. It turned a radioactive red and I had to mask out that color because it stood out like a sore thumb.

    How can I eliminate this Red overkill problem. If you fine folks can solve this one for me then I'll be one very appreciative and happy camper.

    Thanks again for such a fine thread.

    It is not uncommon that if you have some strong colors mixed with some weak colors, the steepening of the A or B channels will overdo the strong colors. There are three basic approaches to dealing with this that I use:
    1. Use Blend If settings to block the effect from the brighter colors. You can get really good at this to the point where it takes only a few seconds.
    2. Change the shape of the curve on the A or B channel so that it doesn't change anything in the brighter colors and only steepens the curve in the mid-colors.
    3. Mask off the effect from the objects that contain the brighter colors.
    I almost never use the third option because one of the first two is usually easier and more accurate, but anything can be masked as a backstop.
    --John
    HomepagePopular
    JFriend's javascript customizationsSecrets for getting fast answers on Dgrin
    Always include a link to your site when posting a question
  • Tom K.Tom K. I post, therefore I am. Posts: 817Registered Users Major grins
    edited September 15, 2006
    I thank you so very much Pathfinder. Superb advice that worked!
    Visit My Web Site ~ http://www.tomkaszuba.com/
  • Tom K.Tom K. I post, therefore I am. Posts: 817Registered Users Major grins
    edited September 15, 2006
    Many thanks jfriend. Advice like this is worth it's weight in gold.
    Visit My Web Site ~ http://www.tomkaszuba.com/
  • maggiedddmaggieddd Beginner grinner Posts: 5Registered Users Beginner grinner
    edited September 26, 2006
    histogram
    I am almost finished with chapter 7 and I have a question. When I use shadow/highlight tool on the L channel, I noticed that the histogram changes (degrades) dramatically. Should I be concerned?
  • jfriendjfriend Scripting dude-volunteer Posts: 24,828Registered Users Major grins
    edited September 26, 2006
    Degraded histogram?
    maggieddd wrote:
    I am almost finished with chapter 7 and I have a question. When I use shadow/highlight tool on the L channel, I noticed that the histogram changes (degrades) dramatically. Should I be concerned?

    The histogram should change when you use shadow/highlights on the L channel. You're changing the luminance of some parts of the image - that should change the histogram.

    Now, when you say that it "degrades", I'm not sure what you mean. If you can post a before/after screen shot of the histogram, we could definitely help you understand what's going on. Absent that, my advice is that there are only a few undesirable characteristics of a histogram. First, you usually shouldn't see pixels crammed up against either edge because this means that some tonal values were clipped (either forced to black or forced to white) and detail has been lost. Second, you probably don't want large empty spaces at either end of your histogram. These large empty spaces either mean your image is overexposed, underexposed or it's just really, really low contrast and thus doens't fill the whole tonal range. This second issue might just be the way the tonal values of your image are in nature or it might be an opportunity to mprove the image in post processing by "stretching out" the tonal values to fill the whole range.

    Beyond these, the histogram is what it is, a view of how the tonal distribution of your image occurs in nature, nothing good or bad about it.
    So, to offer any more advice, we'd have to know why you think the histogram has "degraded" and a picture would be worth a thousand words.

    Here are two good sites to read on interpreting the histogram:

    http://www.luminous-landscape.com/tutorials/understanding-series/understanding-histograms.shtml
    http://www.outbackphoto.com/workflow/wf_41/essay.html
    --John
    HomepagePopular
    JFriend's javascript customizationsSecrets for getting fast answers on Dgrin
    Always include a link to your site when posting a question
  • ruttrutt Cave canem! Posts: 6,511Registered Users Major grins
    edited September 26, 2006
    maggieddd wrote:
    I am almost finished with chapter 7 and I have a question. When I use shadow/highlight tool on the L channel, I noticed that the histogram changes (degrades) dramatically. Should I be concerned?

    And here is description of how to choose shadow/highlight parameters.
    If not now, when?
  • maggiedddmaggieddd Beginner grinner Posts: 5Registered Users Beginner grinner
    edited September 26, 2006
    jfriend wrote:
    The histogram should change when you use shadow/highlights on the L channel. You're changing the luminance of some parts of the image - that should change the histogram.

    Now, when you say that it "degrades", I'm not sure what you mean. If you can post a before/after screen shot of the histogram, we could definitely help you understand what's going on. Absent that, my advice is that there are only a few undesirable characteristics of a histogram. First, you usually shouldn't see pixels crammed up against either edge because this means that some tonal values were clipped (either forced to black or forced to white) and detail has been lost. Second, you probably don't want large empty spaces at either end of your histogram. These large empty spaces either mean your image is overexposed, underexposed or it's just really, really low contrast and thus doens't fill the whole tonal range. This second issue might just be the way the tonal values of your image are in nature or it might be an opportunity to mprove the image in post processing by "stretching out" the tonal values to fill the whole range.

    Beyond these, the histogram is what it is, a view of how the tonal distribution of your image occurs in nature, nothing good or bad about it.
    So, to offer any more advice, we'd have to know why you think the histogram has "degraded" and a picture would be worth a thousand words.

    Here are two good sites to read on interpreting the histogram:

    http://www.luminous-landscape.com/tutorials/understanding-series/understanding-histograms.shtml
    http://www.outbackphoto.com/workflow/wf_41/essay.html
    actually, the histogram "degrades" after I do my things in LAB and then convert to RGB. I said degrades but maybe I am wrong. Maybe I should have said the image degrades accoding to the histogram.
    Please take a look at the histograms

    original image right after RAW conversion
    hist1.jpg

    right after LAB conversion
    rightafterLAB.jpg

    back to RGB after I made my LAB adjustments
    backrgb.jpg
  • jfriendjfriend Scripting dude-volunteer Posts: 24,828Registered Users Major grins
    edited September 26, 2006
    Histogram looks OK to me
    maggieddd wrote:
    actually, the histogram "degrades" after I do my things in LAB and then convert to RGB. I said degrades but maybe I am wrong. Maybe I should have said the image degrades accoding to the histogram.
    Please take a look at the histograms

    original image right after RAW conversion
    hist1.jpg

    right after LAB conversion
    rightafterLAB.jpg

    back to RGB after I made my LAB adjustments
    backrgb.jpg

    In the original histogram, I see a fairly broad distribution of tones that fills the tonal range. There aren't many shadows, but the few shadows that there are have lost detail. I don't see any blown highlights.

    The LAB histogram always looks quite a bit different. I presume you're showing the thing they call the "composite" histogram from LAB mode. I have many images that have a histogram that looks like this in LAB mode. To tell you the truth, I don't know quite how to read the composite histogram. I think what you're seeing is that because LAB is a much, much larger color space, you're seeing a bunching of tones in the center of the color space.

    The final histogram looks fine to me. Your edits pushed a few more tones into the shadows which, depending on the image, might be adding some pop, there are still no blown highlights and the overall tonal range is fairly evenly distributed. It looks like Photoshop may have changed the scale on the histogram too since it shows so much flatter and lower. I don't see anything wrong with this histogram. Looks fine to me.

    I think this is all we need the histogram for. Nothing bad happend from the histogram point of view. Now, you just have to concentrate on what moves would make the image appear visually better. Did it get better? If not, then post the before/after image and tell us what you did and you're likely to get a range of different ideas here.
    --John
    HomepagePopular
    JFriend's javascript customizationsSecrets for getting fast answers on Dgrin
    Always include a link to your site when posting a question
  • maggiedddmaggieddd Beginner grinner Posts: 5Registered Users Beginner grinner
    edited September 26, 2006
    jfriend wrote:
    In the original histogram, I see a fairly broad distribution of tones that fills the tonal range. There aren't many shadows, but the few shadows that there are have lost detail. I don't see any blown highlights.

    The LAB histogram always looks quite a bit different. I presume you're showing the thing they call the "composite" histogram from LAB mode. I have many images that have a histogram that looks like this in LAB mode. To tell you the truth, I don't know quite how to read the composite histogram. I think what you're seeing is that because LAB is a much, much larger color space, you're seeing a bunching of tones in the center of the color space.

    The final histogram looks fine to me. Your edits pushed a few more tones into the shadows which, depending on the image, might be adding some pop, there are still no blown highlights and the overall tonal range is fairly evenly distributed. It looks like Photoshop may have changed the scale on the histogram too since it shows so much flatter and lower. I don't see anything wrong with this histogram. Looks fine to me.

    I think this is all we need the histogram for. Nothing bad happend from the histogram point of view. Now, you just have to concentrate on what moves would make the image appear visually better. Did it get better? If not, then post the before/after image and tell us what you did and you're likely to get a range of different ideas here.
    OK thanks. I wasn't sure what to think of the final histogram. Why would photoshop change scale on the histogram?
    The image definitely looks better, at least in my opinion.
  • maggiedddmaggieddd Beginner grinner Posts: 5Registered Users Beginner grinner
    edited September 26, 2006
    another question. How can I learn how to use Blend if setting?
Sign In or Register to comment.