Also check the resolution…in YT often the video is offered by default at a lower resolution. I always check and select the highest…makes following dialogues, sliders and mouse movements easier…sometimes a video starts at 480p when there is a 1440p version…
Absolutely, GIMP has strengths. I’m happy to “have” it. I was thinking also in terms of offset litho print pre-press, CMYK production work as well as photography. I worked in graphic design for years and that’s whole 'nuther world.
It’s great to have choices, particularly free ones! 
Great videos. Its really nice to see someone doing edits that don’t hurt your eyes !
As a rt user I like seeing abstract profile and locallog being used. I use both for basically the same thing , managing underexposed areas whilst protecting highlights, and find myself hesitating which to use. Its nice seeing someone else using the tools.
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I rarely use RT, but did watch some of Andy’s videos. I like his straight image focused style. You get all information you need, and, thanks for that, not much information you don’t need to edit your images.
Also like that he is using sometimes Photoshop/LR as comparison.
Really fun to watch!
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Hello Andy,
in this video you say: In the Exposure compensation:
in across the entire image it’s left the existing contrast in image and the existing saturation in the image and everything has been turned…
But then you come to Lab and say it again. Is it really true that in Exposure compensation the contrast and saturation are not changed?
I’m the one that put up these links here at pixls, so if you reply to them Andy isn’t going to get noticed about it. Best way to grab his attention is by using his nick like this: @Andy_Astbury1 He’s now going to be notified that someone wants his attention.
No need to do it again for this one though, he’ll see my above “call” and realizes in no time that it is not me that wants him but you.
About your question:
As you can see in the video if you increase the exposure (at ~04:40) in also increases the contrast, which he mentions.
If you skip to ~07:55 you see that increasing the Lightness in L*a*b does not increase the contrast.
Simplified a bit:
- Exposure compensation is done using the RGB channels. More exposure also means more colour which in turn means more contrast.
- L*a*b on the other hands separates lightness, contrast and “colour” (chromaticity). Adjusting one of those sliders does not influence the other 2.
I leave it at this, Andy is the better explainer so I’ll leave it to him to correct me or add any important bits that I forgot.
@Jade_NL
Your explanation is very clear and understandable. Only in Lab Mouds contrast and saturation are not changed. Thank you very much.
My misunderstanding came from the fact that it says so in the video:
05:30 and it’s left the existing contrast in the image
05:35 and the existing saturation in the image and everything has been turned up by
I mostly use the curves and get along well with them.
One question: can you do everything with the curves that Exposure compensation does? And do you need this Exposure compensation at all if you work with the curves anyway?
Assuming for the moment that you are talking about the 6 curves and 3 equalizers in the L*a*b Adjustments section: Yes, you most probably can. But…
I think that the sane approach is to not exclude any of the tools as a starting point. Each image (or image series) needs its own approach and has its own unique challenges.
The image in the 3 Ways to Lighten… video is a nice example: This specific image does not benefit all that much from using the exposure compensation slider, as is explained by Andy. So you need another way of approaching this and Andy shows 2. You could also use the Local Adjustments tab + tool(s) and target specific areas (just an example, this would not be the easiest approach in this case 
).
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Doesn’t Lab have 9 curves and 3 equalizers?
Thanks for your thoughts - it’s complicated but also nice to have these options.
Okay, I’m going to be more humble and stop asking if you can do everything with the curves.
Let me ask you this:
Can you replace the “Exposure compensation” with the RGB curves? What does the curve shape look like that corresponds to “Exposure compensation”?
If I could afford it I’d hire you as my PR manager Jacques 
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OK, here come my thoughts and musings…
First, RGB - any RGB value contains information about the COLOUR & ‘BRIGHTNESS’ of a pixel - supplement whatever word you like for ‘brightness’.
Next, CONTRAST - can be thought of as a ratio of brightest ‘brights’ to darkest ‘darks’ - just as monitors have a contrast ratio and print papers have a dmax and dmin contrast ratio.
The exposure compensation slider is - even though it’s supposed to be an ‘RGB’ control - very useful because it effects every pixel in an image to exactly the same degree.
If we take -1Ev out of an image we take every pixel down by -1Ev irrespective of it being a highlight, midtone or shadow.
HOWEVER - there is a caveat to this!
If we already have a shadow/black value of ‘0 RGB’ we cannot make it any darker by removing -1Ev, but we still drop all the lighter tones by -1Ev thus making them all 1 stop darker, so we DO effect the overall image contrast ratio - we reduce it.
The same can be said if we go the other way with +Ev comp - we will maintain our existing image contrast RATIO by adding +Ev comp right up to the point where our images brightest pixel hits 255(in 8 bit terms). If we continue to add +Ev comp we do indeed make ALL our darks and mids brighter/lighter, but those 255 pixels can’t get any brighter/lighter, so we still end up reducing the image contrast ratio.
But using the Ev comp slider WHILE avoiding CLIPPING of highlights/shadows does not - at least visually - produce any contrast ratio change, becuase it’s a blanket, non-selective, non-curve-based adjustment
But being an RGB style adjustment it WILL lead to a variation in all colours, which is really inconsequential in the grand scheme of things PROVIDED you have not white balanced said image. And even if you have, you can always amend that after the fact.
Curves on the other hand are designed to modify CONTRAST from the get-go, irrespective of whether they are composite RGB or individual channel curves, and they will all effect COLOUR too, with the exception of a Lab L* curve.
With Lab, the L*channel allows for CONTRAST adustment without effecting the colour of the a or b channels, and the lightness slider is a quick way of lightening the image.
Certain popular ‘info suppliers’ rave about curves as if they are something new. But when you’ve worked with Photoshop as long as I have (BarneyScan!) you’ll soon come to realise that everything is a bloody curve!
Sharpening is an edge-localised curve which is distributed on yet another curve.
When you blend layers you do so on a curve - just 'cos you can’t see it doesn’t mean it’s not there!
In Photoshop both curves and levels effect contrast AND produce colour shifts - unless you switch their blend modes from normal to luminosity. Which is one of the many reasons I use Raw Therapee etc to produce an image that needs final tweaks in Photoshop as opposed to a ‘finished’ image - thus leveraging the power of two different sets of tools to produce the final image - there are NO shortcuts in this game IF you want the ultimate in image quality; or if indeed your paying clients demand it. But that’s a whole other story…
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Hi Andy,
watched a couple of your videos. Very nice. Well paced and easy to follow.
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There’s a new RawTherapee Basics video.
The RGB Curves, Modes, Custom Shadow, Mid Tone & Highlight White Balance. (38:34)
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@Andy_Astbury1 : Like many of us I see that you also run into the pull-down-menus-only-half-open-at-times issue (a GTK+ and not an RT bug if I’m informed correctly).
Fastest way to make it open instantly when this happens is to move your mouse pointer over the right hand side widgets. This works for all, not just the misbehaving RGB Curves module.
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I thought it was my Mac!
Cheers for the tip Jacques 
your description of the “Exposure comensation slider” is great - I now really understand why it has a real justification next to the curves. It does something else.
Andy, thank you very much
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Andy made another video:
Raw Therapee Tone Mapping & Wavelet Texture Boost + Photoshop Workflow (31:58)
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