I use Lightroom 99.99% of the time to post-process my images. However recently I started reading a tutorial on Photoshop CS5 and the use of the curves tool. Quite interesting, quite powerful. I'm still learning but I'm amazed how I can control the tone and contrast of an image using this tool. I love the use of the luminosity blending mode to avoid excessive and unnatural color shifting.
Lightroom (3.x) has a curves tool but for the life of me I can't get it to respond like Photoshop's and I can't find the equivalent of luminosity blending mode.
So my question is, is it possible to perform the same corrections inside Lightroom with the curves tool as you can by going to Photoshop/curves? If not, what is missing? Also Is there are way to apply curves only to the luminosity channel? Is the curves tool more powerful in Lightroom 4?
[second question deleted. just figured out the answer]
I find the tone curve in LR extremely sensitive to use compared to Curves in PS. There is also no way to make the tone curve in LR to impact ONLY luminosity. It's impact on saturation and hue is more subtle than a Curves adjustment in PS on a normal layer, but there are changes.
With LR4, the tone curve now allows use to make adjustments to the individual RGB curves. I haven't had a reason to use them though.
Here is some additional reading your might find interesting:
Thomas Knoll and the Adobe team are always faced with making compromises between what is technically correct and what is pleasing to the eye. I suspect that there are two main reasons that they decided to go with different behavior for the LR tone curve:
- LR-only users won't have the other sophisticated tools available to them that are available in PS, so they needed to orient the tool to satisfy most of the the LR users most of the time. The LR tone curve seems to be a bit of a compromise between a "normal layer curves adjustment" and a "luminosity layer curves adjustment" in PS.
- I am not sure but I believe there may be other "behind-the-scene" factors since LR is dealing with the raw data (in the case of raw files), rather than image data that has already been demosaiced, white balanced, and converted to an output color space, like would be the case in PS.
Same goes for me in reverse ... PS uses a 500 scale for sharpening, LR @ 150 (like acr).
Everytime I think about buying LR ... I get put off by the differences @ interface and "DON'T BUY" because of it. I really don't need the hassle of learning a different program that SHOULD be integrated better ...
HopeIsEternal wrote:
I use Lightroom 99.99% of the time to post-process my images. However recently I started reading a tutorial on Photoshop CS5 and the use of the curves tool. Quite interesting, quite powerful. I'm still learning but I'm amazed how I can control the tone and contrast of an image using this tool. I love the use of the luminosity blending mode to avoid excessive and unnatural color shifting.
Lightroom (3.x) has a curves tool but for the life of me I can't get it to respond like Photoshop's and I can't find the equivalent of luminosity blending mode.
So my question is, is it possible to perform the same corrections inside Lightroom with the curves tool as you can by going to Photoshop/curves? If not, what is missing? Also Is there are way to apply curves only to the luminosity channel? Is the curves tool more powerful in Lightroom 4?
[second question deleted. just figured out the answer]...Show more →
In PS, curves are in RGB, LAB and CMYK mode. In LR, RGB only.
In PS, the window size for curves is much larger and more comfortable to work with.
The main reason for the difference in "behavior" isn't anything close to what has been described before (more than in a pragmatical PoV).
The difference is in the working color space. The "curves" in Lightroom always work in the ProPhoto space that is the basis for everything LR does. And previously it worked on the "V" parameter of a Prophoto HSV space - not at all what the photoshop curves are based on.
Now, if you make a curve more steep, you do at the same time increase contrast between the color channels - i.e increase saturation. If you do this is the HUGE ProPhoto space that your raw file is still in in LR, you often block the output - pin a channel to either "0" or "255" - when the data that you manipulated is downconverted to a much smaller Adobe RGB or sRGB space.
There's also a question of stacked changes - the curves are not the last thing that happens to the image before export - there's stuff in between the curve is applied and the point of export. Anything you do with the curve will also change how the stuff between "curves" and the file export works.
In Photoshop the curves work directly in/on the colorspace that your document is currently in, and also very directly on what you see - no middle hands. But try setting your working space to ProPhoto, add four or five additional adjustment layers on top of a curve adjustment layer, and then muck around with the curve adjustment layer again while having the soft-proof option on - set to sRGB. Some funny stuff might happen... This is what you're doing in LR, basically.
Just wanted to respond to a few things that the theSuede mentioned, particularly with an eye to the OP's original questions (i.e., differences between PS and LR curves).
theSuede wrote:
The difference is in the working color space. The "curves" in Lightroom always work in the ProPhoto space that is the basis for everything LR does.
LR does use ProPhoto in terms of color gamut, although the details are a little more complicated (ProPhoto RGB Chromaticities and a linear gamma for processing, but an sRGB gamma tone curve for histogram display). Still I don't think the color gamut is the main difference between PS and LR tone curves is the ProPhoto color space, particularly if you are using ProPhoto as your working space in PS. Yes, you can have saturation clipping issues if your final output is in a smaller color space but that can happen in PS as well.
theSuede wrote:
And previously it worked on the "V" parameter of a Prophoto HSV space - not at all what the photoshop curves are based on.
I think this is a little misleading. If LR adjusted ONLY the "V" in the HSV space, then there would be no changes to saturation and hue and the result would be similar to a curves adjustment layer in luminosity blend mode in PS. What is clear is that LR makes adjustments to "H", "S", and "V" according to lookup tables. The LR team has explained that they do this to produce what most photographers want to see and they have had some influence from film behavior. This treatment has been somewhat controversial in the past and you can find some additional reading material by Googling "lightroom hue twists". Some of the web pages I referenced earlier try to map/compare LR tone curve behavior to PS curves behavior. My general take is that: 1) they are different; 2) the saturation and hue shifts in LR are less than a similar PS curve but saturation and hue are still impacted.
theSuede wrote:
There's also a question of stacked changes - the curves are not the last thing that happens to the image before export - there's stuff in between the curve is applied and the point of export. Anything you do with the curve will also change how the stuff between "curves" and the file export works.
The LR team has explained that the Tone Curve changes are applied after the Basic sliders. The Tone Curve may not be last in the pipeline but it does come after the critical changes to exposure, contrast, highlights, etc..
There is one difference between LR and PS curves that is important and I explained it incorrectly in my first attempt. The Basic and Tone Curve adjustments are applied in the pipeline after demosaicing but underneath the hood, the demosaiced raw data is being manipulated in linear gamma. That means that the right side of the histogram in LR is more "data rich" than the left side and that means that the Tone Curve in LR may be more effective at teasing out details in the highlight areas of an image than waiting until PS.
In reading some recent posts from Eric Chan related to LR4, a member of the Lightroom team, it seems pretty clear that they are doing everything possible to make the Tone Curve a "tool of last resort". They highly recommend using the adjustments in order. The same settings always produce the same results, no matter what order they were applied, but applying the settings in the order they occur in the panels will help the user to avoid a lot of "tail-chasing" due to the interactions among different settings. With the enhancements made to the Basic panel in LR4, it seems pretty clear that they are expecting the Tone Curve to be used only for minor tweaks - not heavy lifting.
n reading some recent posts from Eric Chan related to LR4, a member of the Lightroom team, it seems pretty clear that they are doing everything possible to make the Tone Curve a "tool of last resort". They highly recommend using the adjustments in order. The same settings always produce the same results, no matter what order they were applied, but applying the settings in the order they occur in the panels will help the user to avoid a lot of "tail-chasing" due to the interactions among different settings. With the enhancements made to the Basic panel in LR4, it seems pretty clear that they are expecting the Tone Curve to be used only for minor tweaks - not heavy lifting....Show more →
^^^This.
But the OP asked about LR3; the Tone Curve in LR3 does not have the functionality of the Tone Curve in LR4. For example, RGB Curves were added to LR4 but they aren't in LR3...the workaround in LR3 is to use the Hue/Saturation/Luminance Panel in combination with the Targeted Adjustment tool.
