The first claim seems kind of obvious, doesn't it? You have the opportunity to paint something closer to an experience of a place or scene, but a photo will encourage you to make a reproduction of a scene as taken by a photo.
For colors, I'm assuming that while you can make exactly the color in the photograph, the colors will mix on the canvas leading to a muddying of the colors. I'm not a painter, but I'm guessing you'd want to create brighter colors so that the final result matches your intended color. (And also it's easier to dull colors than to brighten them.)
The web app heavily utilizes the sRGB color space for calculations, which has a limited color gamut. As a result, some colors, especially those outside the sRGB color gamut, may not be accurately represented.
But this is also true for taking photo of your painting and posting it to the social networks. If you can't accept some minimal inaccuracy of a few colors of your painting, you should not post it online and only exhibited it in galleries.
There are a minimum of two colors at play in a photograph: the color of the object, and the color of the light. Picking a color from a photograph is always an average of these two colors and any other interacting factors. When you place a color on a canvas, how it looks depends on the surrounding colors (look up simultaneous contrast for an interesting example).
This is not about how a painting looks online, this is about how the painting itself comes out.
Unfortunately, even well-known college art programs are not always rigorous in teaching theory. Art education is also a far different subject than being an artist. Bad habits are easy to create, and this app encourages shortcuts that create bad habits.
You probably know this, but it gets even worse. Paint can be applied in many translucent layers, and the reflectance of paint materials can differ a lot. The color therefore also changes depending on how you look at the painting and under what lighting conditions.
The same goes for objects, and photos typically capture only a limited subset of this.
I guess the difference here is that I see this as a set of potentially useful tools for someone who already knows what they're doing, and not educational tools for beginners. It certainly doesn't seem to be advertised as such.
they're referring to how an image will get perceived if its flattened in a photo v. experienced with binocular vision. drawing from life is taking 3D and making it 2D. drawing from a photo is taking 2D and keeping it 2D. also it did occur to me a photo will likely struggle to reproduce color as accurately as it occurs in real life. i mean just yesterday i pulled over to take a photo of the rising sun lighting up the underside of mammatus clouds and my iphone couldn't do it justice. i don't think the claim is silly; i was an art major at one point and went through this very discussion in my life drawing class.
Some things of note:
- Drawing from photos (a flattened image) teaches you to draw what the camera sees, not what you see.
- Picking colors from a photograph is a quick way to choose muddy colors.