How many colors/hues are there in AP? (Color Replacement Issues)

[buddingphotographer]

Hi guys, I'm trying to replace colors in a photo, and I'm not able to re-create the exact color/tint/hue that I want.

Evidently "hue" only refers to approximately 360 different "colors" in affinity. (Pardon my ignorance of the difference in definitions). So am I seriously limited to 360 options for replacement?

Surely I'm missing something, what is it?

 

[Alfred]

5 minutes ago, buddingphotographer said:

Evidently "hue" only refers to approximately 360 different "colors" in affinity. (Pardon my ignorance of the difference in definitions). So am I seriously limited to 360 options for replacement?

Surely I'm missing something, what is it?

 

What you seem to be missing is the fact that each colour model has a different 'gamut', or range of possible values. CMYK, for example, has a (much) smaller gamut than RGB.

 

The HSL model is indeed limited to whole numbers of degrees around the colour wheel, corresponding to the hue, so there are exactly (rather than approximately) 360 different hues.

 

[buddingphotographer]

I realize that there are different gamuts, and I actually tried changing color spaces in the vain hope that I would get a different result.

I guess my question really is: How do I get a variation on one of the 360 "hues" available?

[Alfred]

41 minutes ago, buddingphotographer said:

I guess my question really is: How do I get a variation on one of the 360 "hues" available?

 

I take it all back! I was thinking of the HSL controls in the Colour panel, but I see that the Hue control for a Recolour adjustment allows for tenths of a degree. Is that an insufficient amount variation for you, or is the problem that you apparently have to adjust the lightness separately? 

 

[buddingphotographer]

All I am trying to do is change the color of a wall from light yellow to light blue (as in the screenshot in my first post) I was following this tutorial: https://www.youtube.com/watch?v=3i45_kBOOqg (Color a layer, then change it to the "Hue" blend mode)

It works exactly how I want it to, except that I can't get the shade of blue that I want (far left on the screenshot above)

Any ideas?

[R C-R]

In the tutorial, the user is painting on a pixel layer. You apparently are using a rectangle layer, which is not the top layer, nor is its opacity set to 100%. Try moving it to the top in the Layers panel, & set its opacity to 100%.

[buddingphotographer]

Yes, I'm using a rectangle layer, but as far as I could tell, the principle is the same as a pixel layer. I originally used a pixel layer, then switched to a rectangle layer because it was easier to change the color on a rectangle for testing purposes. I tried reducing the opacity to see if that would bring the color closer to what I wanted, but it didn't.

 

[R C-R]

Color is determined by a combination of multiple parameters, like hue, saturation, & lightness (HSL) or red, blue, & green (RGB), plus opacity. If you use the Hue layer blending mode, you will only affect the hue contributed by the color of the rectangle. In the tutorial, the user has chosen the hue blend so the saturation & lightness of the car's pixels will be unaffected -- otherwise, it would be a solid blob of color with no details like the headlights, wheels, etc.

 

So if you do not need to preserve any details on the wall, like a texture, just use the normal blend mode. Otherwise, you will need to adjust all three parameters to get what you want, as well as trying another blend mode besides hue.

[carl123]

Hue and colour are not the same thing

If you want to match the blue colour on the far left of the screen and add it to your rectangle just sample the colour you want with the colour picker and use the brush to apply it.

 

 

[buddingphotographer]

1 hour ago, carl123 said:

Hue and colour are not the same thing

Thanks, I'm beginning to realize that.

If I do what you suggested, that's fine until I change the blend mode to "hue", then all of a sudden the "color" suddenly changes to a much brighter blue.

[R C-R]

@buddingphotographer You may find the Cambridge In Colour article A Background on Color Perception useful in understanding why hue & color are not the same thing. Another article from the same site, Understanding Bit Depth, should answer your questions about how many colors are available in an image's color palette.

 

In my opinion, the Cambridge In Colour web site is one of the best online sources for digital color & related information. In particular, all of the Color Management & Printing tutorials are worth reading. They are concise, reasonably comprehensive, & no more technical than they need to be.

[R C-R]

1 minute ago, buddingphotographer said:

If I do what you suggested, that's fine until I change the blend mode to "hue", then all of a sudden the "color" suddenly changes to a much brighter blue.

So don't do that! 

[buddingphotographer]

Thanks for the links, @R C-R. I agree, CIC is an excellent place to go for good technical info on all things color and photography.

I understand from that article that there are theoretically ~16,000,000 colors available in an 8-bit RGB image. All I want is one color!! (actually, I guess it would be a gradient technically) I realize that "color" and "hue" are not the same thing, but I still don't see why that should prevent me from getting the shade of blue that I need.

There has to me some work-around that allows me to adjust the other aspects of "color".

Quote

So don't do that! 

I have to, if I want it to look natural. This is a wall in a photo, not a digital painting.

[R C-R]

From what you have said so far, what you want is neither a single color nor a gradient, both of which would create an unnatural looking digital painting effect (because either one would hide all the details of the wall, similar to how the paint in the tutorial you mentioned hides the car's details up to the 2:08 or so mark when he changes the blend mode).

 

There are many different techniques that will get the effect you want, for example by using a HSL adjustment layer & masking as demonstrated here, but it will never be as simple as selecting one color (which has a single set of hue, saturation, & lightness values) to cover the entire wall.

 

You may find some of the official Affinity Photo video tutorials helpful for this, particularly those in the Corrections section, for example the Adjustment Layers & Changing Eye Colour ones.

[carl123]

56 minutes ago, buddingphotographer said:

 

.........I have to, if I want it to look natural. This is a wall in a photo, not a digital painting.

It's very hard from the screenshot you posted to see what texture is on the wall

There are other techniques such as adding noise, using texture brushes, sampling the texture on the wall and then creating your own brush etc that can help you blend the brush stokes better.

If you want to upload the original photo and just say what you want to do with it, people here may be able to suggest different techniques to achieve that

[toltec]

It is a lot easier to just select a marquee area, copy it to a new layer and

 

resize to fit.

 

Right colour and texture too.

 

A little bit of inpainting on the edges. and delete the little bit where the top of the cupboard(?) is.

[buddingphotographer]

Thanks for all the suggestions guys. I've learned a few things about how "color" works, so I guess it was educational.

I found that selecting the region I want to re-color and using a HSL Adjustment layer gives me a bit more control over the fine-tuning of color. (Still nothing like I would have thought possible though)