I'm not able to reproduce anyhting like it with the lightness/brightness/L* controls and sliders in RawTherapee. Indeed something that is not otherwise available. It seems that every pixel is at the maximum brightness possible while still allowing the saturation and hue of the original pixel. The other colour models cannot emulate that. The unique property of the HSV model is that clipping is not possible whatever operations are applied to the brightness channel. That works only provided the brightness is not increased to the level at which clipping occurs (which may be different for different pixels). Depending on which one you select only that aspect of the photo will be affected.Īlso clicking the hand icon in the Hue/Saturation window allows you to pick any colour in the layer by clicking on it and it then broaden or narrow your selection as you wish. For instance apply a curve to a layer but apply blending mode of Hue, Saturation, Colour, or Luminosity rather than the default normal blend mode. You can do this in photoshop with blending modes. This is mathematically not possible with HSV. Usually this appears as the colours becoming washed out when they are brightened to the stage where clipping occurs in one or more colour channels. I think in all the other models, the hue and saturation can get changed when the image is brightened. Without getting too deep into the mathematics, the unique feature of HSV is that no matter how much you brighten the image, the hue and saturation never get changed. I am not sure, but I think that HSL is often distinguished from HSV by using a different definition for L from that used for V.Īlthough for many purposes the two models will produce the same results, the differences appear when the value of the brightness (whether L or V) is increased towards the maximum. Uglier than GIMP I'd say, and probably less usable.

I haven't used it since CS2 so I could be wrong, but here's an image that might be it. I think Photoshop has this, though it might be buried deep in the menus. I use it to produce brighter, lower contrast images without losing colour - for 'artistic' purposes.

Using LAB colour in Photoshop will often produce the same effects, but the advantage of using HSV is that the 'value' (brightness) can be changed without any risk of altering the hue or saturation, even when the brightness is increased to the maximum. I suspect it is not available in other common photo editors. When I last looked, it was not available in Photoshop and the Adobe software. I regularly use the HSV colour model in GIMP.

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