blend mode "saturation"

[NotMyFault]

12 hours ago, anon2 said:

You've been told why the results do not match your expectation. Affinity's Saturation blend mode, like that of Photoshop and several other apps which produce the same result, is intentionally not performing HSL saturation blending. Similarly, Luminosity blend mode is intentionally not performing HSL lightness blending.

Wy so harsh? I understood this a few replies before. Dave asked a question, i replied to him, not to you.

I agree that the blend mode works as designed (by Adobe ages before) - except that i cannot reproduce some text book example images in Affinity, the effect is kind of stronger here.

what i miss is 2 blend modes using HSL logic

1. S based on HSL

2. L based on HSL

3. And a proper documentation (Online help) that gives this simple explanation, and stops citing the misleading shortened descriptions.

 

[dmstraker]

I'm slightly confused. Sorry, normal state. Nevertheless hugely enjoying the exploration and learning.

So blend modes use Hue, Chroma, Luma, as per https://en.wikipedia.org/wiki/Blend_modes#Hue,_saturation_and_luminosity

I'm guessing other HSL controls are done as Hue, Saturation and Luminosity/lightness using https://en.wikipedia.org/wiki/HSL_and_HSV#Color_conversion_formulae

So is the question about confusion when one meets the other?

 

 

 

[v_kyr]

Further, according to Adobe's PDF Ref manual ...

Quote

7.2.3 Blending Color Space

Note that the compositing formula shown above is actually a vector function: thecolors it operates on are represented in the form of n-element vectors, where nisthe number of components required by the color space in which compositing isperformed. The ith component of the result color Cris obtained by applying the compositing formula to the ith components of the constituent colors Cb, Cs, and B(Cb, Cs). The result of the computation thus depends on the color space in which the colors are represented. For this reason, the color space used for compositing, called the blending color space, is explicitly made part of the transparent imaging model. When necessary, backdrop and source colors are converted to the blending color space prior to the compositing computation.

Of the PDF color spaces described in Section 4.5, “Color Spaces,” the following are supported as blending color spaces:

•DeviceGray
•DeviceRGB
•DeviceCMYK
•CalGray
•CalRGB
•ICCBased color spaces equivalent to those above (including calibrated CMYK)

The Lab space and ICCBased spaces that represent lightness and chromaticityseparately (such as L*a*b*, L*u*v*, and HSV) are not allowed as blending colorspaces, because the compositing computations in such spaces do not givemeaningful results when applied separately to each component. In addition, an ICCBased space used as a blending color space must be bidirectional; that is, the ICC profile must contain both AToB and BToA transformations.

The blending color space is consulted only for process colors. Although blending can also be done on individual spot colors specified in a Separation or DeviceN color space, such colors are never converted to a blending color space (except inthe case where they first revert to their alternate color space, as described under“Separation Color Spaces” on page 201 and “DeviceN Color Spaces” on page205). Instead, the specified color components are blended individually with thecorresponding components of the backdrop. The blend functions for the various blend modes assume that the range for eachcolor component is 0.0 to 1.0 and that the color space is additive. The formercondition is true for all of the allowed blending color spaces, but the latter is not. Inparticular, the DeviceCMYK, Separation, and DeviceN spaces are subtractive. When performing blending operations in subtractive color spaces, it is assumed that the color component values are complemented (subtracted from 1.0) before the blend function is applied and that the results of the function are then complemented back before being used. This adjustment makes the effects of the various blend modes numerically consistent across all color spaces. However, the actual visual effect produced by a given blend mode still depends on the color space. Blending in a device color space produces device-dependent results, whereas in a CIE-based space it produces results that are consistent across all devices. See Section 7.6, “Color Space and Rendering Issues,” for additional details concerning color spaces.

 

[Dan C]

Please see my response here -

Your test documents are using P3, not sRGB and this is causing the blend mode differences from the referenced sites

[NotMyFault]

20 minutes ago, Dan C said:

Please see my response here -

Your test documents are using P3, not sRGB and this is causing the blend mode differences from the referenced sites

Thanks, Dan!

I will run the comparisons again.

[NotMyFault]

Hi, 

i know have a working live filter conversion RGB to HSL and HSL to RGB.

This gives full control to access H S L channels individually.