RGB in raw dialog

[KSpodnik]

when using PWP's raw dialog, there are only two options for modifications in highlights-midtones-shadows sliders: HSV or HSL color space. Brightening image in HSV gives oversaturated bright tones, in HSL color space, bright tones are pale. RGB color space gives me usually best colors, inbetween HSL and HSV color space. is there some special reason, why this common color space is not present as option in raw dialog? should it be so difficult to add it here?

[jsachs]

The HSV and HSL color spaces separate out color (more precisely called chroma) from brightness so you can adjust the brightness without altering hue and saturation. Applying a curve in RGB generally means applying the save curve to each channel which changes hue and saturation along with brightness. It also makes it a lot easier to clip individual channels.

[KSpodnik]

by technical point of view you are absolutely right. HS is separated from V(L) value.

BUT:

V in HSV means: from black (0) to medium (50) and to fully saturated (100% saturation),
L in HSL means: from black (0) to medium (100% saturated) and to white (0 saturation)

for portrait work, rising brightness (V) of midtones in HSV means that saturated skin becomes awfully saturated, in HSL rising brightness (L) of midtones makes bright skin tones become awfully pale. for this reasons IMHO these color spaces are absolutely inadequate for portrait work (maybe should be interesting hear opinion of other members).
RGB color space changes in midtones means changes in brightness and saturation in all channels (as you said), but with more pleasing result, and without any clipping, if not moving 100% point (right border of the curve).

[jsachs]

Increasing brightness in HSV simply scales all the channels by the same factor so it preserves the ratios between R, G and B and thus should not make colors look more saturated.

[ksinkel]

In addition to the brightness control, the raw dialog also has an exposure control. Use the exposure control if you want to affect each channel by the same amount. As Jon has mentioned, the limit on increasing exposure is generally reached when the first channel saturates. If you have headroom (as when the image is actually underexposed) this is the correct control to use since there is room before saturation becomes a problem. However if the exposure is correct increasing brightness with the brightness slider is usually the better option for the reason Jon mentioned. Of course there are cases when you may want to violate this rule and accept some saturation in the highlights.

Finally there is no loss of information if you decide not to make brightness adjustments in the raw dialog but instead make them using the brightness curve or one of the other brightness dialogs in a separate step.

Kiril

[KSpodnik]

Once again, I do perfectly understand advantages of HSV/HSL color spaces, that is not a problem.

as for analog photography correct exposure means aperture + shutter speed + iso, for DSLR correct exposure (looking at histogram of in-camera jpeg) means aperture + shutter speed + iso + applied in-camera curves (is well known that raw file opened in dcraw without brightness correction is usually darker than in camera jpeg - guess why?)
all camera manufacturers do apply in camera brightness curves when converting raw data to final jpeg (and i guess it is in RGB, only for example so do Adobe camera raw, too - but for sure there is some reason why they are using RGB).

I give you one example:

If I want to match the exposure of raw file to thumbnail jpeg, i have 2 possibilities:
1) move exposure slider to the right (if there is any headroom, or you get blown highlights)
or/and
2) move midtones slider to the right (brightening image without creating blown highlights) with awful oversaturated (HSV) or pale bright tones (HSL)

sure, PW workflow is 1) converting raw to tiff with exposure compensation (slider in raw dialog) and than 2) apply any curves, level and color and so on - so we will get image that we want (and this works nicely).

BUT:

PW has nice feature of camera default setting in raw dialog (default exposure, midtones, shadows... compensation suitable for each camera model).
If there could be possibility of applying sliders in RGB (default setting for camera model) directly in raw dialog (because HSV/HSL is not working good here for reasons mentioned before), in this case should be necessary only to move exposure slider to perfectly match exposure of in camera jpeg file, with much less postprocessing needed.

As I sad before, RGB does not achieve awful oversaturated (HSV) or pale bright tones (HSL) when rising midtones slider. For this reason I ask you, if there is any problem about adding RGB color space in raw dialog - for me (and maybe also for many others), raw conversion would be much faster, and converting second, third, fourth... raw file would be easy only moving exposure slider if needed.

[ksinkel]

Could you send me a sample image that exhibits what you are describing and the wfl file you used in Raw to adjust it, so I can see what you are experiencing. You can send it to support@dl-c.com. Since the files are large, you will need to use a file transfer service.

Kiril