Don’t know what to call it (blend?)

[MikkelN]

Hello!

This is my first post on a GIMP-forum.
I want to buy a custom mouse mat, as no good desk-sized ones exist with a black/green theme without ugly logos.
So I wanted to make my own image to print into the mat.
The image consists of light, which I’ve changed to green, however, I wanted different “grades” of green, as the light “fades” to black.
Is it possible to make GIMP change to green and automatically choose shade based on intensity of white/gray (light)?
Also, if I have 2 separate layers of green, one being “brighter/more intense than the other, is there a way to “blend” the 2 layers by inserting different shades of green?

Any help is appreciated!

[Blighty]

Without seeing your image it isn't possible to give a definite answer. There are several ways to create a blend.

One way is to use a gradient eg a green to black gradient. Use the Gradient Tool to fill in the gradient (blend).

Another way is to use blurring eg for the two shades of green. Usually Filters > Blur > Gaussian Blur.

Both methods will probably need a selection to limit where the effect is applied.

Be sure to start off with the correct canvas size. The printer of the mat will have more info on this. Nothing worse than starting off with an image that is too small and then becomes blurry when scaled up.

[MikkelN]

(05-03-2019, 03:19 PM)Blighty Wrote: Without seeing your image it isn't possible to give a definite answer. There are several ways to create a blend.

One way is to use a gradient eg a green to black gradient. Use the Gradient Tool to fill in the gradient (blend).

Another way is to use blurring eg for the two shades of green. Usually Filters > Blur > Gaussian Blur.

Both methods will probably need a selection to limit where the effect is applied.

Be sure to start off with the correct canvas size. The printer of the mat will have more info on this. Nothing worse than starting off with an image that is too small and then becomes blurry when scaled up.

I think I figured it out.
I played around with it a bit and I'm pretty happy with the result.

Don't worry, the image is 21600x10800. I hope that's high enough for a mousepad.

---

But if I wanted to convert an image with a range from black to white (grayscale) to an image with a range from black to green, how would I be able to do this?
Say there are around 30 different shades of gray/white, how would I make GIMP color the appropriate amount of green? - Say 1 pixel has a value of 66%. How do I make that pixel 66% green?
Is this done with the gradient tool? And if so, is there a place where I can read/watch an in-depth guide?

[Blighty]

(05-03-2019, 07:47 PM)MikkelN Wrote: But if I wanted to convert an image with a range from black to white (grayscale) to an image with a range from black to green, how would I be able to do this?

Several ways that give slightly different results.

1. Colors > Colorize

2. Create a black to green gradient.
Colors > Map > Gradient Map