Why is 'tint' at 3% more than at a higher %? I think its a bug

[lacerto]

Thanks for your tests.

However, I have some comments.

a) We do not know (it is not explicit to the user) what kind of calculation (and blend mode) is performed on RGB/CMYK color image and the applied color. It cannot be reproduced with any of the predefined blend modes, though the way colors blend resembles most the "Color" blend mode.

b) Applying tint in the "Color" blend mode does affect the underlying image as the tint value is decreased. Applying tint in the "Hue" blend mode however does not (it does for certain color combinations but barely not at all in most cases). 

c) In both "Hue" and "Color" blend mode setting the Tint value to zero does make the underlying image grayscale. This is expected since basically both blend modes use luminosity of the underlying image to blend the applied color. When the tint value is zero, only the luminosity (intensity of the color values) is effective.

Below is an example of applying "Hue" and "Color" blend modes in InDesign and Affinity Publisher. The effect is basically identical in both apps, except that InDesign does not allow direct assignment of color to an RGB or CMYK image. The video also shows the anomaly with low tint values, and shows that assigning a direct color value is not the same as applying either of these predefined blend modes.

a) Tints and blends in InDesign:

 

b) Tints and blends in Affinity Publisher:

 

I think that these videos show that we cannot expect that adjusting the Tint slider in Affinity Publisher should affect the coloring of an RGB/CMYK image when used in context of an image that has a direct color assignment, because we know nothing about the way blending of the color values is done. However I think that the fact that the image turns grayscale at zero tint value is expected. So basically the only glitch might just be the fluctuation of the coloring at low tint values, which I guess is a rounding error (near zero values turn off part of the channels).

[Dan C]

21 hours ago, Lagarto said:

We do not know (it is not explicit to the user) what kind of calculation (and blend mode) is performed on RGB/CMYK color image and the applied color. It cannot be reproduced with any of the predefined blend modes, though the way colors blend resembles most the "Color" blend mode.

I've asked the developers to confirm this for me (if possible) and I'll be sure to update this thread with any information provided  

21 hours ago, Lagarto said:

In both "Hue" and "Color" blend mode setting the Tint value to zero does make the underlying image grayscale. This is expected since basically both blend modes use luminosity of the underlying image to blend the applied color. When the tint value is zero, only the luminosity (intensity of the color values) is effective.

Thank you for this information, it's certainly helpful and I can see how a 0% tint would produce a greyscale image now - so I do agree this is likely expected behaviour!

21 hours ago, Lagarto said:

I think that these videos show that we cannot expect that adjusting the Tint slider in Affinity Publisher should affect the coloring of an RGB/CMYK image when used in context of an image that has a direct color assignment, because we know nothing about the way blending of the color values is done. However I think that the fact that the image turns grayscale at zero tint value is expected. So basically the only glitch might just be the fluctuation of the coloring at low tint values, which I guess is a rounding error (near zero values turn off part of the channels).

I agree regarding the rounding error and this is logged with our developers - as regardless of the 'blending mode' in use when applying a fill directly to an image layer, I certainly wouldn't expect the fluctuations when using a low % tint value. Hopefully further confirmation from the developers will help explain this further!

[Bryce]

If you select the colored image then choose the "K" button, then select the color in the swatch palette, the tint slider works n