Curves are curves and levels are levels?

[HeinrichR]

Is curves just curves and levels, levels, when applied to the Raw file in lightroom/acr, vs. done to the same (unedited raw)file exported from lightroom as a tiff/psd and the curves/levels then applied in CS, I presume there would be a difference when its applied to the raw file in lightroom?

[SteveG]

Don't know all the differences but there definitely are some differences:

Curves adjustments in PS also include a default saturation adjustment, unless you select blending mode to be "luminosity". Adjusting curves (and exposure and brightness and contrast) in LR also affects saturation, but differently, to a lesser extent I think. Haven't played with it enough to get a handle on what it does.

Levels in PS also affects saturation. Again you can avoid this by selecting luminosity blending. I don't know how LR differs from PS in this regard.

I did an eyeball test last year some time: apply a significant curve/levels adjustment to an image, normal blending, and compare it to the result you get from the same adjustment with luminosity blending. Then try and increase saturation on the latter till it resembles the former. I needed something like +20 overall saturation to match the two.

[cagenuts]

I think the old LR3 and ACR6.5 are the same in terms of levels and curves but now that LR4 is out there are differences.

[HeinrichR]

Thanks, Steve , Hilton
suppose curves'levels(no difference in saturation etc.) are the same in lightroom and CS would it be possible to get the same image if one is done in LRoom, and the other exported from lightroom as a tiff/psd with no adjustments to CS , what im after is in lightroom when you apply the curves you do it to Raw data, where if you use the unadjusted tiff/psd in cs you're almost working on a jpg (or tiff, its not a raw file anymore)?

[cagenuts]

Your question is a tad confusing but I'll try and answer as best as I can.

Without a doubt, it's better to set the curves and levels in a RAW processor before moving the file to a Pixel manipulating software like Photoshop. Having said that, if you make use of layers in Photoshop you still have the option of changing that layer, assuming you then save the file as a .psd or .tiff but if you save it as a .jpg then the layers will be gone.

One major reason to use LR for curves and levels is that after the fact you want to change something, you can open the .tiff file directly in Photoshop and then switch back to ACR to change the levels. Adobe hasn't made LR available for this back door edit option.

Not sure if I've been of any help here?

[Karin Leibbrandt]

To be honest:
I wish one of you guys would give an explanation for idiots, sort of a curves/levels 101.
I sometimes manage to create amazing results with curves, yet I know it is capable of more.
I have no idea what levels are for.

[cagenuts]

Levels are for curve noobs.

[Karin Leibbrandt]

Levels are for curve noobs.

thanks... I think.

[HeinrichR]

thanks Hilton.

[cagenuts]

Ok to clarify. Using levels it's easy to see what you're doing and it's even easier to drag the marker back. The main downside of using levels is that the adjustment affects all the blacks or all the highlights whereas with curves the power is now turned up considerably giving you finite control as to where exactly you want to change values. So you could click on the sky and drag down to decrease saturation for a certain colour only, something levels won't do.

The biggest obstacle to using curves is the understanding of what the x & y axis values mean at any given point.

[Forgiss - Sean Nel]

http://www.cambridgeincolour.com/tut...hop-curves.htm - extremely basic, starting point introduction to curves...

Curves are super powerful, it's not only contrast and exposure, it's split according to your channels and over multiple colour modes. heck, you can even use your curves to effect sharpening!

About levels is a *page*
About curves is a BOOK!

[SteveG]

Thanks, Steve , Hilton
suppose curves'levels(no difference in saturation etc.) are the same in lightroom and CS would it be possible to get the same image if one is done in LRoom, and the other exported from lightroom as a tiff/psd with no adjustments to CS , what im after is in lightroom when you apply the curves you do it to Raw data, where if you use the unadjusted tiff/psd in cs you're almost working on a jpg (or tiff, its not a raw file anymore)?

Something worth understanding wrt this is that you are NOT working with Raw data in Lightroom. The image you see is a 16-bit tiff rendered from your raw file and any curves/levels you apply in LR are applied to this tiff. So if, as you suppose, the curves and levels adjustments in LR and CS are the same then yes, you can get the same image in both apps.

I suspect that if you tried it you would find differences between the images in each app. I think that the curves and levels tools in CS and LR use different algorithms.

[HeinrichR]

Thanks Hilton, Stephen, and Sean for the link, makes more sense now.

[Forgiss - Sean Nel]

Just read a post my wifey mad a day or so ago on her blog about preparing images for pre-press. I asked her about the statement:

Version 1: Total ink brought to about 260%, resulting in a less contrast, but possibly safer printing version, with more shadow detail. I used Curves to re-distribute inks and lower densities.

... and how much she actually uses curves... Answer: almost on every adjustment layer separately split across multiple colour channels...

Blog post here for those that may be interested (RETOUCH: Chianosky for VOILA, 02-2012)

[cagenuts]

Luba certainly knows her stuff Sean. I perused her website and I especially liked this delightful snippet "My partner, Sean Nel is the most balanced person I know".

[Forgiss - Sean Nel]

Luba certainly knows her stuff Sean. I perused her website and I especially liked this delightful snippet "My partner, Sean Nel is the most balanced person I know".

Hahahahaha... I do believe that was in reference to balancing light sources but yes, she is a photoshop monster!

[HeinrichR]

Something worth understanding wrt this is that you are NOT working with Raw data in Lightroom. The image you see is a 16-bit tiff rendered from your raw file and any curves/levels you apply in LR are applied to this tiff.

OK I thought because its a raw converter everything you change in LR is changes to the raw data, never really bothered to investigate this, so is the RAW changes just in the top panel, and all changes in the panels below(levels/curves etc) are changes to the tiff created from that raw file?
and then, in photoshops raw converter, there are also a curves section, is that then also applied to a tiff/psd file created from the file you created in the panel with the exposure/brightness/etc in that raw converter

Just read a post my wifey mad a day or so ago on her blog about preparing images for pre-press. I asked her about the statement:
... and how much she actually uses curves... Answer: almost on every adjustment layer separately split across multiple colour channels...

Blog post here for those that may be interested (RETOUCH: Chianosky for VOILA, 02-2012)

thanks will check the link now.