Photoshop Lab Color: Ch. 1

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  • ThusieThusie Major grins OhioRegistered Users Posts: 1,818 Major grins
    edited January 11, 2006
    I hope for some help here. I have been workin off and on with this shot all morning using the basic LAB and USM in Lightness. Yes it's a squirrel:D but they seem to be what I do best and my minds eye knows what they should look like, most of the time. This shot drove me nuts! I appreciate your time.

    51972728-L.jpg

    51972327-S.jpg

    51972343-S.jpg

    51972352-S.jpg

    51972312-L.jpg
  • ruttrutt Cave canem! BostonRegistered Users Posts: 6,511 Major grins
    edited January 11, 2006
    Thusie wrote:
    I hope for some help here.

    Looks a lot better to me, but maybe you don't like the orange that has crept into the background and coat? Try more conservative A+B steepening. Try 5%, 10%.
    If not now, when?
  • ruttrutt Cave canem! BostonRegistered Users Posts: 6,511 Major grins
    edited January 11, 2006
    rutt wrote:
    Looks a lot better to me, but maybe you don't like the orange that has crept into the background and coat? Try more conservative A+B steepening. Try 5%, 10%.

    Oh, and I just noticed that your A and B curves aren't steepened by the same amount. Is there a reason for that, or just oversight.
    If not now, when?
  • jfriendjfriend Scripting dude-volunteer San Francisco Bay Area, CaliforniaRegistered Users Posts: 8,097 Major grins
    edited January 11, 2006
    Use Blend If to exclude background from steepened A and B channels
    rutt wrote:
    Looks a lot better to me, but maybe you don't like the orange that has crept into the background and coat? Try more conservative A+B steepening. Try 5%, 10%.

    When I played with this one, I liked that with some steeper A and B curves, you could start to see some of the color in the squirrel, but clearly the background went nuts and really detracted. At first I started thinking about a mask for the background (you can find a channel that, when steepened makes an OK mask), but then I realized that you can just use the BlendIf sliders on the L channel on the steepened A and B curves because there's clear tonal separation between the squirrel and the background (the background is pretty much completely brighter than the squirrel). So, you can draw color out of the squirrel without overdoing the background.

    I've got to learn that lesson that before I go to a mask, try blendif.

    Sorry, I can't post a result right now, but thought I'd share this idea.
    --John
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  • ThusieThusie Major grins OhioRegistered Users Posts: 1,818 Major grins
    edited January 11, 2006
    John,

    I'm real basic or real beginner with all this, blending will be for another time me thinks:): Yes I also like the squirrel with the steeper curves but the orange, yeow!

    Rutt what I was trying to do was keep keep the brown in the coat w/o the popping orange so tried setting the a&b a bit different. Didn't work. Plus I think I looked at it way too long
    So here tis with a&b both set to 5%, I like this much better. Used the (lower) eye for a black point and the lightest spot I could find for the white, that made working with the lightness curve much easier.

    I think this is better?

    51979611-L.jpg

    51979636-S.jpg
  • jfriendjfriend Scripting dude-volunteer San Francisco Bay Area, CaliforniaRegistered Users Posts: 8,097 Major grins
    edited January 11, 2006
    30% curves, blocked from the background
    Thusie wrote:
    John,

    I'm real basic or real beginner with all this, blending will be for another time me thinks:): Yes I also like the squirrel with the steeper curves but the orange, yeow!

    Rutt what I was trying to do was keep keep the brown in the coat w/o the popping orange so tried setting the a&b a bit different. Didn't work. Plus I think I looked at it way too long
    So here tis with a&b both set to 5%, I like this much better. Used the (lower) eye for a black point and the lightest spot I could find for the white, that made working with the lightness curve much easier.

    I think this is better?

    How does this one work for you? This is a drastically steeper A and B (30% on each end) where the effect has been mostly blocked from the background so it's just the squirrel that gets the benefit. It's also got an L curve that tries to bring out more detail in the tones of the squirrel. If you're interested, I can explain how I did this, but probably can't do it until tonight.

    51988603-L.jpg
    --John
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  • ThusieThusie Major grins OhioRegistered Users Posts: 1,818 Major grins
    edited January 11, 2006
    John,

    If you have the time I would certainly appreciate the 'how to', I think it would come in quite handy.

    Thanks!
  • ruttrutt Cave canem! BostonRegistered Users Posts: 6,511 Major grins
    edited January 11, 2006
    Thusie wrote:

    I think this is better?

    51979611-S.jpg

    I love him now. You might be just a little braver with that L curve to try to lighten up a bit and get more detail in the fur. Try pulling down the quatertones a touch (that means making a point on the curve about 1/4 of the way over and pulling it downward just a little. You want the curve a bit steepper in the area of the fur. You might have to make another point near the right hand side and pull it upward.

    There are all kinds of ways to limit the color the A and B curves introduce when they get too steep. John really really wants to show you how to do that, but the best way to learn is either to plow forward through the reading group posts and/or (preferably) buy Dan's LAB book.
    If not now, when?
  • ginger_55ginger_55 Crazy Creek Babe Charleston, SCRegistered Users Posts: 8,416 Major grins
    edited January 11, 2006
    "Blend if" sliders on the L curve??? To keep the background out of the mix????

    g (It looks very good, Blend if (?) )
    After all is said and done, it is the sweet tea.
  • ThusieThusie Major grins OhioRegistered Users Posts: 1,818 Major grins
    edited January 11, 2006
    rutt wrote:
    I love him now. You might be just a little braver with that L curve to try to lighten up a bit and get more detail in the fur.

    There are all kinds of ways to limit the color the A and B curves introduce when they get too steep. John really really wants to show you how to do that, but the best way to learn is either to plow forward through the reading group posts and/or (preferably) buy Dan's LAB book.

    Thank you Rutt and I will work on the L curve. I have been reading the group posts and printing some things. For some reason I have always done better with something in hand than reading on the netne_nau.gif We have a start, small one but a start.:):
  • ruttrutt Cave canem! BostonRegistered Users Posts: 6,511 Major grins
    edited January 11, 2006
    ginger_55 wrote:
    "Blend if" sliders on the L curve??? To keep the background out of the mix????

    g (It looks very good, Blend if (?) )

    Ginger, it's a more advanceced technique. Pathfinder describes it in his Chapter 7 summary. I covered it right at the top of my Chapter 8 summary. And since I happen to know for absolute sure that you have this book and haven't read it, I'll give you a page reference: 157-159 and, better, 174-177.

    Next time I want to hide money from you, I'll put it in a book.

    Anyway, you don't need this fancy stuff in order to use this simple recipe and get great results. Learn to simple A+B steepening and learn how to write good L curves and you'll be able to improve lots and lots of your shots and you'll be ready to go on to more advanced stuff. Only Ginger has no excuse.
    If not now, when?
  • Phil_LPhil_L Major grins SwedenRegistered Users Posts: 106 Major grins
    edited March 22, 2007
    Late comer
    I tried the tutorial as an experiment, since I am planning to buy the book.

    The results were totally amazing in relation to the time spent tweaking the pics.

    thumb.gifiloveyou.gif

    It is probably worth mentioning in the tut that you can do all the tweaks on adjustment layers, if you want to be able to go back for adjustments!??

    I am still plowing through Barry Hanes book PS Artistry.

    Will these threads remain open so I can come and play at a later Date?
  • ruttrutt Cave canem! BostonRegistered Users Posts: 6,511 Major grins
    edited March 22, 2007
    This thread will remain open as long as dgrin does.
    Phil_L wrote:
    I tried the tutorial as an experiment, since I am planning to buy the book.

    The results were totally amazing in relation to the time spent tweaking the pics.

    thumb.gifiloveyou.gif

    It is probably worth mentioning in the tut that you can do all the tweaks on adjustment layers, if you want to be able to go back for adjustments!??

    I am still plowing through Barry Hanes book PS Artistry.

    Will these threads remain open so I can come and play at a later Date?
    If not now, when?
  • Phil_LPhil_L Major grins SwedenRegistered Users Posts: 106 Major grins
    edited April 28, 2007
    I have taken the quick and dirty tour of the first six chapters of the book and I am completely blown away by the raw (:D ) power availible in L*A*B*.

    Here are two examples of reworking using curves steepening:

    1) Snap shot of a house in the Swiss ski resort Andermatt.
    Dates back to before the Napoleonic wars and today maintained in original shape by the town council!
    Camera 3.0 MP Oly P&S.
    Chickened out of taking my DSLR skiing.ne_nau.gif

    Before

    147519786-L.jpg

    After steepening curves. Fairly agressive with a and b.

    147519715-L.jpg


    Tell me if you think it is overcooked.

    Yes I know there are blown highlights and blocked shadows.:D


    2) From the summer palace of August the Strong of Saxony (also King elect of Poland) on the outskirts of Dresden in Germany.
    Camera D70 with AF-S 12-24 f4.

    Before

    147520214-L.jpg


    After the steepening of curves

    147520543-L.jpg

    Actually tweaked the sky on a seperate layer but still.
    Could probably have been more agressive with the steepening?

    Sorry dont know how to do screen shots! ne_nau.gif

    Going to review what I have covered before attacking the rest of the book.

    For those who havent tried it yet:
    If you have a reasonable understanding of curves and PS you can get a lot out of this book and be up and running, without having to digest the whole thing .
    Dont be put off by the for geeks only rep of the book!


    fwiw
  • JimWJimW Major grins New York CityRegistered Users Posts: 333 Major grins
    edited June 10, 2007
    Margulis LAB - Chapter 1
    I just got the LAB book (Canyon Conundrum), and so far have read chapter one, as well as Rutt’s excellent synopsis. I know I’m about a year and a half late, but better late than never. After years on the road doing color correction for the printing industry, I’m retiring from press okays (mostly – still have one client), and concentrating on photography. So I’m familiar with cmyk, and starting to learn rgb color correction, when I happened to notice this section of the forum. I’m used to fashion clients going berserk if the seafoam green shirt isn’t perfect, so the lunacy of spending ridiculous amounts of time & effort getting an image just right seems completely normal to me, and I love it.

    I started practicing on a recent wedding I shot 2 weeks ago in St Augustine, Florida. This wedding was as close to shooting blind as I’ve ever come. It was in the afternoon, on the beach, and there wasn’t a cloud in the sky until the very end. I’ve spent much of my life in dark pressrooms, and live in a small dark NYC apartment, so for me this wedding was like shooting on the surface of the sun. I shot with my dark shades on, and still couldn’t see a thing. I kept saying to myself, “just don’t overexpose”. So I overcompensated a tad. :D I think the ambient exposures are okay, but I failed to get enough flash into the subjects on all these “formals” in the sand dunes. I think I’ll have to retire my Lumiquest bounce card thing, as most of the flash never reached the subjects. Oops.

    This is the final image of the day, and the sun was behind some thin clouds. First one shows the raw settings with no adjustment.

    161276193-O.jpg161276193-O.jpg
    161276201-L.jpg

    Then I processed the image through RAW twice, once for the sky (dark) and a second time for everything else. Here are the RAW settings for the “light” version (everything except sky).
    161282855-L.jpg
    I’ve never had to add so much exposure in RAW before, but it appears to have worked.

    Then I merged them in PS and masked around the grass and dunes to let the darker sky show through. Next I brightened the sand & people slightly with an rgb curve. Then I used jfriend’s method of lightening on an overlay layer for the flesh only (which I just found in the “dark eyes” thread). Then I curved the sky layer only to add contrast to the clouds & sky, and (still in rgb) got this:

    161276176-O.jpg
    161276203-L.jpg


    Then I flattened, took it into LAB, and applied the following curves:
    161299921-O.jpg

    and got this.

    161276169-O.jpg


    The clouds are neutral grey, although blue is a little high compared to red & green, but, coming from the printing world I see that as a good thing (insurance for on-press issues). My original goals were to brighten the sand & people a lot, while showing good value in the sky. I paid particular attention to the flesh tones. In this case, I don’t care about being accurate to the scene. The scene was brutally bright and difficult. I just want a nice photo for them. I’m very pleasantly surprised with the amount of improvement I was able to get, and so far have been very impressed with LAB results. In most cases, the LAB versions look almost as if they were (dare I say?) ... backlit (at least as compared to the rgb version). I capture in Adobe RGB, and should note that when I converted these to srgb for uploading, some of the warmth disappeared.

    All comments and critiques are most welcome. I want to learn, and hope to keep reading and following Rutt’s synopses of the chapters. I really want to add LAB processing to my toolbox of processing tricks, and am enthused by the support here. Thanks very much for this opportunity. (Have I made this post too long?)

    Jim

    I don't want the cheese, I just want to get out of the trap.


    http://www.jimwhitakerphotography.com/
  • DavidTODavidTO Mod Emeritus Thousand Oaks, CARegistered Users, Retired Mod Posts: 19,160 Major grins
    edited June 10, 2007
    Hey, Jim, nice work! Glad you found the LAB stuff here, it's really powerful, and a hoot, to boot!

    I merged your thread with this one, so that everyone can stay on track with Chapter 1 and follow along with your work, as well!
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  • JimWJimW Major grins New York CityRegistered Users Posts: 333 Major grins
    edited June 19, 2007
    Chapter 2
    Thanks David. It helps me to write it down and post work on each chapter, and maybe it’ll help someone else too. The results I'm getting so far are great, but it leaves me wanting a better understanding, so I'm determined to keep going.

    I’ve studied chapter two and understand that:

    Positive numbers indicate warm colors, negative numbers indicate cool colors.
    Zero is no color, a neutral.
    The L is slightly lighter, and higher in midtone contrast, than if we converted to grayscale.
    On the L scale, 100 is light and 0 is dark.
    (It helped me to know that the scale of 0-100 for the L channel still represents 256 levels, and that Photoshop just reports it as 0-100 for our ease of use.)

    Skies almost always fall to the green, not the magenta, side of blue.
    Grass, and stuff that grows, is always to the yellow, never the blue, side of green.

    In rgb, to determine if something will be neutral, all three channels must be compared. In LAB, there is a fixed neutrality inherent in each channel. If the object is at 0 on the A channel, we don’t have to compare it to any other channels, it will be neutral in that channel.

    For practice, I processed this file as rgb with the following curve:

    164265429-Th.jpg

    164265494-L.jpg


    Then I processed as LAB with the following curves:

    161299921-S.jpg

    164265459-L.jpg



    Question: For the rgb version, I flattened, reduced size from 300 dpi to 72 dpi, then sharpened using unsharp mask, at (85, 1.0, 4). For the LAB version, I sharpened the Lightness channel in LAB using unsharp mask at (200, 1.0, 8 as the author suggests), then flattened, converted to rgb, reduced size to 72 dpi.
    Why does the rgb look sharp but the LAB doesn’t? (Maybe I should wait for the sharpening chapter?)


    Comments and/or help is welcome. Thanks, Jim.

    I don't want the cheese, I just want to get out of the trap.


    http://www.jimwhitakerphotography.com/
  • canoflancanoflan Major grins Cypress, TexasRegistered Users Posts: 168 Major grins
    edited June 19, 2007
    Why are you resizing 300 to 72 then back?
    Question: For the rgb version, I flattened, reduced size from 300 dpi to 72 dpi, then sharpened using unsharp mask, at (85, 1.0, 4). For the LAB version, I sharpened the Lightness channel in LAB using unsharp mask at (200, 1.0, 8 as the author suggests), then flattened, converted to rgb, reduced size to 72 dpi.
    Why does the rgb look sharp but the LAB doesn’t? (Maybe I should wait for the sharpening chapter?)


    Comments and/or help is welcome. Thanks, Jim.[/quote]

    Why are you moving from 300 to 72 and back? Does Dan's book say to do this? I have his book and didn't read that in it. If he talks about resizing, can you direct me to the chapter? Thanks.
  • JimWJimW Major grins New York CityRegistered Users Posts: 333 Major grins
    edited June 19, 2007
    I'm not going from 300 to 72 and back, just from 300 to 72, in order to post online here with a smaller file. I don't think I really completely understand the dpi issue yet.

    It's not from the book. I just thought I should reduce the size because monitors only show 72 anyways.

    I don't want the cheese, I just want to get out of the trap.


    http://www.jimwhitakerphotography.com/
  • canoflancanoflan Major grins Cypress, TexasRegistered Users Posts: 168 Major grins
    edited June 19, 2007
    Understood
    I understand. Just another case of me overthinking things.
  • jfriendjfriend Scripting dude-volunteer San Francisco Bay Area, CaliforniaRegistered Users Posts: 8,097 Major grins
    edited June 19, 2007
    JimW wrote:
    Question: For the rgb version, I flattened, reduced size from 300 dpi to 72 dpi, then sharpened using unsharp mask, at (85, 1.0, 4). For the LAB version, I sharpened the Lightness channel in LAB using unsharp mask at (200, 1.0, 8 as the author suggests), then flattened, converted to rgb, reduced size to 72 dpi.
    Why does the rgb look sharp but the LAB doesn’t? (Maybe I should wait for the sharpening chapter?)

    Comments and/or help is welcome. Thanks, Jim.
    If you post a link to the original image (probably in a Smugmug gallery), we can take a look at it for ourselves.

    Perceived sharpness comes from a variety of operations. I actually find that the most pronounced contributor to sharpness is contrast. In most cases, higher contrast things will look sharper. Without seeing the original myself, I can't tell for sure, but I think you may be seeing a contrast difference between these two images, particularly in the tones that cover the bricks.

    Some things that affect sharpness are:
    • Contrast (as I said above)
    • Your sharpening process (I've found I have to sharpen the L-channel much stronger than an RGB sharpening operation)
    • Your resizing process before viewing on the web
    • Your sharpening process after resizing for the web
    Now, on resizing for the web, it is a lot easier to completely forget about dpi. The web works in pixels, not dpi and not in inches. What you want to do is to resize your image for the web to a specific pixel dimension. It doesn't matter at all what the labelled dpi or image dimensions are on the web. Those are just stamped attributes on the image that have nothing to do with the actual pixels in the image and have nothing to do with how a browser displays them.

    For a little reading material on resizing for web display, here are couple links:

    http://www.cambridgeincolour.com/tutorials/image-resize-for-web.htm
    http://www.infinitee-designs.com/Save-for-the-Web.htm

    For posting here, I don't resize the images myself. Instead, I upload the original to a non-public Smugmug gallery that I use just for posting images in forums, I let Smugmug generate the various sizes and I then link in either the -M or the -L version here. When Smugmug does the creation of those sizes, it not only resizes, but also adds a bit of sharpening and it saves me lots of time to just let them do the work for me automatically.
    --John
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  • JimWJimW Major grins New York CityRegistered Users Posts: 333 Major grins
    edited June 20, 2007
    Yet another very helpful post John. Thanks for taking the time.
    If you post a link to the original image (probably in a Smugmug gallery), we can take a look at it for ourselves
    Since I have been posting 72 dpi only, this wouldn’t help, right? By “original image”, I think you mean hi res (300 dpi)?
    I actually find that the most pronounced contributor to sharpness is contrast. In most cases, higher contrast things will look sharper
    I understand and agree.
    I've found I have to sharpen the L-channel much stronger than an RGB sharpening operation
    I’m just beginning to notice this, too.
    Your sharpening process after resizing for the web
    Yes, I think that’s the key, especially after reading the first of your links. On the LAB version, I sharpened in LAB, then converted back to rgb, then downsized BUT did not resharpen after downsizing. I think I should have. But, at least in the first two chapters, he didn’t mention this.
    It doesn't matter at all what the labelled dpi or image dimensions are on the web. Those are just stamped attributes on the image that have nothing to do with the actual pixels in the image and have nothing to do with how a browser displays them.
    Hmm, it’s taking a while for that to sink in. So, if I upload an image to my galleries (non-public, as you said), for posting here, it makes NO difference whether I upload 300 dpi versus 72 dpi? However, it must make a difference on sharpening, since a 72 dpi image seems to show sharpening much quicker than a 300 dpi image?
    let Smugmug generate the various sizes and I then link in either the -M or the -L version here. When Smugmug does the creation of those sizes, it not only resizes, but also adds a bit of sharpening
    So you must get used to knowing how much SM will sharpen, and you can adjust your sharpening accordingly?

    [FONT=&quot]Really appreciate the help. Jim

    [/FONT]

    I don't want the cheese, I just want to get out of the trap.


    http://www.jimwhitakerphotography.com/
  • jfriendjfriend Scripting dude-volunteer San Francisco Bay Area, CaliforniaRegistered Users Posts: 8,097 Major grins
    edited June 20, 2007
    JimW wrote:
    Yet another very helpful post John. Thanks for taking the time.

    Since I have been posting 72 dpi only, this wouldn’t help, right? By “original image”, I think you mean hi res (300 dpi)?

    Hmm, it’s taking a while for that to sink in. So, if I upload an image to my galleries (non-public, as you said), for posting here, it makes NO difference whether I upload 300 dpi versus 72 dpi? However, it must make a difference on sharpening, since a 72 dpi image seems to show sharpening much quicker than a 300 dpi image?

    So you must get used to knowing how much SM will sharpen, and you can adjust your sharpening accordingly?[FONT=&quot]
    [/FONT]
    By "original image", I meant a full resolution image (the original pixels with no resizing) that you haven't yet done post processing on. Then, we could see for ourselves what influences sharpness the most in that image.

    For the web, ALL that matters in this regard is how many pixels the image has. An image with 12 megapixels will be a lot different than an image with 2 megapixels, particularly in relation to sharpening as you have noticed.

    The dpi rating is actually just a metadata tag on the image (or derived from some other metadata tags). It can be changed from 72 dpi to 300 dpi without changing the pixels of the image one bit and thus without changing the display on the web one bit. For the web, you should learn to ignore the dpi value and start to focus only on how many pixels you have. As it turns out, the workflow you were using to change dpi was also changing the number of pixels so it "seemed" like the right thing to do, but it is not the best thing to look at.

    That's kind of like watching the tachometer in your car to see how fast you're going. It's sometimes an indication of how fast you're going (and sometimes not because of gear changes), but watching the speedometer is a much more direct way to keep track of your speed that is never misleading. For the web, keep your eye on the number of pixels, not the dpi rating.

    On Smugmug, I sharpen my high-res versions the way I like them and Smugmug does a good job of preserving that "look" when they create smaller, downrezzed versions of the images. There are many different methods and opinions on sharpening so this is just how I do it - there are lots of other viewpoints too.
    --John
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  • JimWJimW Major grins New York CityRegistered Users Posts: 333 Major grins
    edited June 20, 2007
    It (dpi) can be changed from 72 dpi to 300 dpi without changing the pixels of the image one bit
    Ok, I think I get that. If you change dpi from 72 to 300, you still have the same number of pixels, and the same file size, but now they will make a smaller image size. Yes, Ok.
    For the web, you should learn to ignore the dpi value and start to focus only on how many pixels you have
    I'm getting it now.
    As it turns out, the workflow you were using to change dpi was also changing the number of pixels so it "seemed" like the right thing to do, but it is not the best thing to look at.
    I'm afraid I lost you there.

    Here is the way I was taught to change a 300 dpi image for uploading to the web:

    Open an “original” image, full res with all original pixels
    Open Image/Image size
    Uncheck resample
    Change resolution to 72
    Re-check resample
    Change pixel width (or height-whichever is bigger) to 800 px.
    Click OK.

    I have always done this when preparing images for uploading or for emailing. Now I’m beginning to suspect that I’m not doing it right, or that it’s unnecessary.
    On Smugmug, I sharpen my high-res versions the way I like them
    Wait, please. The way you like them for what, print OR web? In my experience, they are totally different. Are they the same for you?

    I jumped into Photoshop learning curves and masks to get work done, mostly inkjet prints, and now I realize I should go back and learn the basics. I’ve got big gaps in my postprocessing knowledge, which are now driving me crazy.

    :bash

    I don't want the cheese, I just want to get out of the trap.


    http://www.jimwhitakerphotography.com/
  • jfriendjfriend Scripting dude-volunteer San Francisco Bay Area, CaliforniaRegistered Users Posts: 8,097 Major grins
    edited June 20, 2007
    JimW wrote:
    Ok, I think I get that. If you change dpi from 72 to 300, you still have the same number of pixels, and the same file size, but now they will make a smaller image size. Yes, Ok.
    Displaying an image in Smugmug or elsewhere on the web has absolutely nothing to do with the dpi. You are right that if you keep the pixels the same and change the dpi from 72 to 300, the labeled image size will go down, but that's just a label on the image and hardly anything these days uses that value so I just ignore it.

    What that labeled size was made for was printing, but ALL software that I use for printing lets me tell it how big I want the output print to be which is a specific instruction to ignore the labeled size on the image. That's why it's largely irrelevant.
    JimW wrote:
    I'm afraid I lost you there.

    Here is the way I was taught to change a 300 dpi image for uploading to the web:

    Open an “original” image, full res with all original pixels
    Open Image/Image size
    Uncheck resample
    Change resolution to 72
    Re-check resample
    Change pixel width (or height-whichever is bigger) to 800 px.
    Click OK.

    I have always done this when preparing images for uploading or for emailing. Now I’m beginning to suspect that I’m not doing it right, or that it’s unnecessary.
    OK, I thought you were changing the dpi with resampling ON. Since you are separately changing the pixel width, you can just drop the steps that change the resolution. They are not needed for any web uses or printing uses where the printer is told what size print to make.
    JimW wrote:
    Wait, please. The way you like them for what, print OR web? In my experience, they are totally different. Are they the same for you?
    If you use Smugmug for both web viewing and printing, then you are, by definition, using the same high res image as the source for both. As such, you have to strike a balance in your sharpening so it can meet both needs. I am not one of those people who spends a lot of time optimizing the sharpening of an image for a particular purpose. I tend to do general purpose sharpening that seems to work fine for both prints and web. I realize there are other opinions on this topic, but I don't try to get that complicated or that optimized.
    --John
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  • JimWJimW Major grins New York CityRegistered Users Posts: 333 Major grins
    edited June 20, 2007
    John, I understand and sincerely appreciate your valuable help. I have learned.

    Jim

    I don't want the cheese, I just want to get out of the trap.


    http://www.jimwhitakerphotography.com/
  • MyerMyer Big grins South FloridaRegistered Users Posts: 25 Big grins
    edited July 5, 2007
    Anybody Still Here?
    After reading the book, LAB has become my colorspace of choice for my enhancements.

    My standard process has become:

    "S" curve area of significance in L
    Slope A and B between 10-15%. I find more often looks artificial.
    Highlight/Shadow to bring back dark areas (Shadow) and remove haze and glare (Highlight).
    Sharpen - USM
    = = = = = =
    I have found that the most bang appears to be in the Highlight area. Removing the glare seems to be the part that adds a lot of crispness to the end result.
    = = = = = =
    I'm considering moving this step to the start and then continue as required once the glare is gone.

    Comments and experiences would be most welcome.
  • StevenLStevenL Beginner grinner Kansas, USARegistered Users Posts: 1 Beginner grinner
    edited March 7, 2008
    I'm new here, so please forgive me if I screw up my reply... an old thread anyway, so may go unnoticed
    jfriend wrote:
    Perceived sharpness comes from a variety of operations. I actually find that the most pronounced contributor to sharpness is contrast. In most cases, higher contrast things will look sharper.

    My understanding of some of the things John brought up here are a little different, so I thought I might post them to try to stimulate further discussion, and help better my understanding.

    Concerning the quote above, the way I learned it, contrast is not just the most pronounced contributor to perceived sharpness, it's the ONLY contributor. The only things that change from one sharpening technique to the other are the way the edges of contrast are selected, and how the contrast is applied.
    jfriend wrote:
    Some things that affect sharpness are:
    • Your sharpening process (I've found I have to sharpen the L-channel much stronger than an RGB sharpening operation)
    On this one (of four) points John listed, I wonder if the need for more sharpening on the L channel in LAB mode, compared to sharpening in the RGB mode, is related to the fact that you're not sharpening (increasing the contrast of) the colors, but only the luminosity. When I do high pass sharpening in RGB mode I always use two clipping layers, one a levels adjustment layer to vary the amount of sharpening (contrast) of the high pass layer, and sandwiched in between those two a hue/sat layer set to desaturate 100%, to avoid any color fringing or halos from the sharpening.
    jfriend wrote:
    Now, on resizing for the web, it is a lot easier to completely forget about dpi. The web works in pixels, not dpi and not in inches. What you want to do is to resize your image for the web to a specific pixel dimension. It doesn't matter at all what the labelled dpi or image dimensions are on the web. Those are just stamped attributes on the image that have nothing to do with the actual pixels in the image and have nothing to do with how a browser displays them.
    Here I think there was confusion about dpi, ppi, and resizing of an image. I think John sorted it out nicely in subsequent posts, but for my own clarification I'll relate my process for posting to the web. What this is about isn't really resizing the viewing size, but actually resampling the image. For print, the aforementioned 300 ppi, or so, is preferred, but for monitor/web viewing I always resample (downsample, as in throw out all the extra data the monitor can't use) the image to 72 ppi to keep the file size as small as possible while retaining as much of the image quality as I can with the conversion to the sRBG color space, and with the losses inherent in jpeg compression. Unlike John, I find significant differences are required in how I sharpen for print output as compared to web viewing output, and save different version of each file destined for both kinds of output.
    jfriend wrote:
    For posting here, I don't resize the images myself. Instead, I upload the original to a non-public Smugmug gallery that I use just for posting images in forums, I let Smugmug generate the various sizes and I then link in either the -M or the -L version here. When Smugmug does the creation of those sizes, it not only resizes, but also adds a bit of sharpening and it saves me lots of time to just let them do the work for me automatically.
    I suspect what this means is Smugmug is doing the downsampling and resizing for you. Since I do my own web output sharpening, I'm not sure I'd like any further sharpening done to my posted images... is there any way around that?
  • hobbeshobbes Big grins Registered Users Posts: 18 Big grins
    edited October 8, 2008
    rutt wrote:
    Click on the bar at the bottom of the curves dialog. It will reverse the scale of darkness to lightness (or warm to cool in A or B). At the same time it will show percentages instead of absolute numbers.

    Dan likes the curves with darkness on the right and I've gotten used to that as well. PS doesn't have consistent defaults. RGB defaults to lightness on the left and LAB and CMYK are the opposite. Dan always has lightness on the left.

    This is just what I was looking for this morning. I'm using cs3 on a mac and can't get the lightness to switch to the left. Anyone know what I'm missing?

    Thanks
  • RichardRichard Mildly bemused Madrid, SpainAdministrators, Vanilla Admin Posts: 19,692 moderator
    edited October 8, 2008
    hobbes wrote:
    This is just what I was looking for this morning. I'm using cs3 on a mac and can't get the lightness to switch to the left. Anyone know what I'm missing?

    Thanks

    I have the Windows version of CS3 but I think this applies to Mac as well:

    Open a curves adjustment layer. Below the histogram there is a widget to display curves options. Click on that so that the full options are displayed. There is a pair of radio buttons labeled "Show amount of:" Clicking Pigment/Ink % will put the bright values on the left. Click OK and PS will remember the setting.
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