Hallo an alle, die RT gut kennen
hello to all who know RT well
wie kann man mit RT am besten die Helligkeit und damit den Charakter des Bilds zu verändern?
Es gibt ja den Regler: Belichtung → Helligkeit, der das Bild heller macht. Ist der Effekt dieses Reglers der gleiche, wie wenn man bei der Kurve die Mitte anfasst und nach oben oder unten bewegt?
Und es gibt den sehr effektiven Filter: Schatten/Lichter. Kann die Kurve-Parametric das gleiche tun oder sogar besser? Ist es sinnvoll, beide gleichzeitig zu verwenden oder ersetzt Kurve-Parametric den Filter Schatten/Lichter komplett?
Lightness
How can I adjust a raw file to change the brightness and thus the character of the image?
There is the slider: Exposure → Lightness, it makes the picture brighter. Is the effect of this slider the same as when you grab the center of the curve and move it up or down?
And there is a very effective filter: Shadows/Lights. Can the curve parametric do the same or even better? Does it make sense to use both at the same time or does Curve Parametric completely replace the Shadow/Lights filter?
These are good questions to have. Since no one has responded so far, I will give it a go.
First of all, the general understanding of exposure is that if your data is in a linear space, increasing exposure means doubling the values and decreasing, the halving. This means that it is different from lifting the mid-tones on a curve (and what to do with a curve also depends on whether it is perceptual or linear).
A good way to start is to understand how curves and basic tools work. For that you have
There is a difference. Curves let you deal with different aspects of the brightness spectrum; example: brighten the mids, or shadows, while leaving highlights alone. The Shadows/Lights tool will do a similar thing but according to some algorithm that I am not aware of what it is.
And yes you can definitely use them together. I do all the time. Whatever produces the result that you want
Hallo stefan.chirila,
thanks for the answer.
If Shadows/Lights is similar to Curve Parametric, I think it makes sense to use only one of the two tools, so that there is no danger of changing something with one, which the other has to compensate. Can the curve parametric completely replace the Shadow/Lights filter? Or can Shadow/Lights restore the highlights better?
micha
I personally do my editing like this:
Use the brightness/lightness in RGB (first tool set) and bring that to about what I like
Then I use the contrast slider to bring it closer to the overall contrast
Then I use the curves below to get the black end to be as dark as I want it to, and then boost the brightness further using the curve still.
Sometimes I change the brightness slider and/or the contrast one, based on whether I think the effect is too strong, or too weak. I do it like I do cooking, mostly according to taste
Hallo afre,
many thanks for the good suggestions. Cambirdgeincolor is new for me - I browse and read there with enthusiasm.
I already knew the rawpedia pages, they are clearly written and very helpful. I adhere quite exactly to these specifications.
In the Advanced section it is recommended to “… continue with using both tone curves”. That’s exactly what I want to do now. But I would also like to understand. Therefore two questions:
What does the slider do: Exposure → Lightness? Is it the same effect as raising the value in the middle of the curve?
and
Can the Shadows/Lights filter be completely replaced by a curve, e.g. parametric? I find it helpful if I work with a few tools, e.g. only the curves. In this way I learn to understand them better and better. When does it make sense to use both (Kurves and Lightness) at the same time?
micha
My recommendation is “luminosity” in the “lab”-module.
And the curve cannot replace the shadows/highlights tool because the latter is more sophisticated since it uses masks. It can recover more highlights and shadows.
Yes, curves are a global adjustment while shadows/highlights are a local adjustment, it’s easier to recover more details with local adjustments but they could introduce artifact like haloes.
In the end it’s a matter of taste, generally I avoid using shadows/highlights because curves looks more natural to me, and I really would use the LAB color space only for sharpen, denoise or the hue-sat equalizer.
Hallo betazoid,
vielen Dank.
Das klingt sehr interessant, doch wie finde ich diese Luminosity im Lab-Modus? Bitte zeige mir, wie das geht.
Und danke für die klare Antwort zu dem Schatten/Lichter Filter, das verstehe ich jetzt gut.
that sounds very interesting, but how do I find this luminosity in Lab mode? Please show me how it works.
And thanks for the clear answer to the shadow/light filter, I understand that well now.
well the L curve or its effect looks a bit strange because it only manipulates the luminosity but not saturation or hue - on the contrary to the normal RGB curve. but that is actually the good thing about it. usually the the saturation/chrominance needs to be increased as well. and you need to tweak the contrast slider too.
Hallo betazoid,
meinst Du die Lab*-Anpassung im Reiter Belichtung. Gut. Aber welche der Kurven meinst Du mit luminosity? Ist es die erste, L*: L=f(L) Luminanz als Funktion der Luminanz? Wenn ja, dann finde ich diese Kurve auch ganz toll, weil beim Anheben des Kontrastes, die Farbigkeit nicht automatitsch mit verändert wird. Das führt in den RGB-Kurven zu unangenehm bunten Farben.
Meinst Du diese Kurve?
micha
ich verstehe.
Das könnte Dich interessieren, aber vielleicht kennst Du es schon: Die “NURBS-Kurve”, die verändert alles so geschmeidig und zart. Und sehr gerne nehme ich auch die “Parametrisch”.
micha
PS. ich möchte mich demnächst mit dem Schärfen RL-Dekonvolut beschäftigen. Ein unglaublich toller Filter, aber manchmal macht er viel mehr hässliche Artefakte als USM. Ich möchte herausbekommen, wann er sinnvoll anzuwenden ist, (vermutlich bei guten Aufnahmen mit reichlich Licht) und wann nicht.
@micha I believe I answered your first question but the screenshots by @age might be more useful to you than my English. That is mainly why I suggested the Cambridge in colour site. It has plenty of visual examples. Well, it looks like you are being helped by other people. I hope you will find what you are looking for.
Same for me, specifically because if you keep the lower-left and upper-right curve control points at 0,0 and 255,255 respectively (assuming 0-255 curve domain), all the curve spline algorithms I know will maintain some sort of graduated transition down to black and up to white, a form of “highlight preservation”. Ramping up exposure past a point will just start to pile up the data at white…
